Grade 11 Physical Sciences Chemistry — Free State practice
Notes
Answer every question. Show the formula, the substitution, and the answer with units. Calculators allowed. These are original practice papers in the style of the province, not a copy of a department PDF.
90 min · 87 Marks · 30 questions
Learn the paper in the app: notes, a marks breakdown, the formula you need, and the board working. You do not need to download it.
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: NaCl is held together by
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: NaCl is held together by. Circle that word — that is the missing variable.
Find
We are required to find: NaCl is held together by. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Metal and non-metal, large electronegativity difference: ionic. Then substitute the given, one line at a time, to get NaCl is held together by.
In other words — as if you have never seen this before
Metal and non-metal, large electronegativity difference: ionic.
2. What do we already know?
NaCl is held together by
3. Which method — and why this one?
Metal and non-metal, large electronegativity difference: ionic.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: NaCl is held together by. Circle that word — that is the missing variable.
Find: We are required to find: NaCl is held together by. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Metal and non-metal, large electronegativity difference: ionic. Then substitute the given, one line at a time, to get NaCl is held together by.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
NaCl is held together by
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Metal and non-metal, large electronegativity difference: ionic.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
Metal and non-metal, large electronegativity difference: ionic.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
ionic bonds
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
ionic bonds
Copy onto your answer sheet — in this order
Answer: ionic bonds
6. Check it like a marker
Metal and non-metal, large electronegativity difference: ionic.
7. A trap first-timers fall into
hydrogen bonds
1.2 · 6 Marks
c = nV. n = 0.01 mol in 0.25 dm³. c =
Notes: c = nV. n = 0.01 mol in 0.25 dm³. c =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: c = nV. n = 0.01 mol in 0.25 dm³. c =
Before any working — hunt first
Given
Numbers and units already in the sentence: 0.01 mol · 0.25 dm³. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c =. Circle that word — that is the missing variable.
Find
We are required to find: c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: c = 0. Then substitute the given, one line at a time, to get c =.
In other words — as if you have never seen this before
c=0.010.25=0.04 mol·dm⁻³.
2. What do we already know?
c = nV. n = 0.01 mol in 0.25 dm³. c =
3. Which method — and why this one?
c=0.010.25=0.04 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 0.01 mol · 0.25 dm³. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c =. Circle that word — that is the missing variable.
Find: We are required to find: c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: c = 0. Then substitute the given, one line at a time, to get c =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
c = nV. n = 0.01 mol in 0.25 dm³. c =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
c=0.010.25=0.04 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
c=0.010.25=0.04 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.04 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.04 mol·dm⁻³
Copy onto your answer sheet — in this order
Answer: 0.04 mol·dm⁻³
6. Check it like a marker
c=0.010.25=0.04 mol·dm⁻³.
7. A trap first-timers fall into
0.003 mol·dm⁻³
2.1 · 6 Marks
ΔH = −286 kJ·mol⁻¹ means the reaction
Notes: ΔH = −286 kJ·mol⁻¹ means the reaction
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: ΔH = −286 kJ·mol⁻¹ means the reaction
Before any working — hunt first
Given
Numbers and units already in the sentence: 286 kJ·mol⁻¹. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: ΔH = −286 kJ·mol⁻¹ means the reaction. Circle that word — that is the missing variable.
Find
We are required to find: ΔH = −286 kJ·mol⁻¹ means the reaction. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Negative ΔH is exothermic: heat leaves the system. Then substitute the given, one line at a time, to get ΔH = −286 kJ·mol⁻¹ means the reaction.
In other words — as if you have never seen this before
Negative ΔH is exothermic: heat leaves the system.
2. What do we already know?
ΔH = −286 kJ·mol⁻¹ means the reaction
3. Which method — and why this one?
Negative ΔH is exothermic: heat leaves the system.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 286 kJ·mol⁻¹. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: ΔH = −286 kJ·mol⁻¹ means the reaction. Circle that word — that is the missing variable.
Find: We are required to find: ΔH = −286 kJ·mol⁻¹ means the reaction. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Negative ΔH is exothermic: heat leaves the system. Then substitute the given, one line at a time, to get ΔH = −286 kJ·mol⁻¹ means the reaction.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
ΔH = −286 kJ·mol⁻¹ means the reaction
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Negative ΔH is exothermic: heat leaves the system.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
Negative ΔH is exothermic: heat leaves the system.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
releases heat
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
releases heat
Copy onto your answer sheet — in this order
Answer: releases heat
6. Check it like a marker
Negative ΔH is exothermic: heat leaves the system.
7. A trap first-timers fall into
absorbs heat
2.2 · 8 Marks
20.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Bloemfontein lab. 1:1. c(NaOH) =
Notes: 20.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Bloemfontein lab. 1:1. c(NaOH) =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 20.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Bloemfontein lab. 1:1. c(NaOH) =
Before any working — hunt first
Given
Numbers and units already in the sentence: 20.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find
We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
In other words — as if you have never seen this before
n(HCl)=0.100×0.020. c=n0.025=0.08 mol·dm⁻³.
2. What do we already know?
20.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Bloemfontein lab. 1:1. c(NaOH) =
3. Which method — and why this one?
n(HCl)=0.100×0.020. c=n0.025=0.08 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 20.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find: We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
20.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Bloemfontein lab. 1:1. c(NaOH) =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
n(HCl)=0.100×0.020. c=n0.025=0.08 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
n(HCl)=0.100×0.020. c=n0.025=0.08 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.08 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.08 mol·dm⁻³
Copy onto your answer sheet — in this order
Answer: 0.08 mol·dm⁻³
6. Check it like a marker
n(HCl)=0.100×0.020. c=n0.025=0.08 mol·dm⁻³.
7. A trap first-timers fall into
0.120 mol·dm⁻³
3.1 · 6 Marks
A bond between two non-metals that share electrons is
Notes: A bond between two non-metals that share electrons is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A bond between two non-metals that share electrons is
In other words — as if you have never seen this before
Sharing, not transferring, is covalent.
2. What do we already know?
A bond between two non-metals that share electrons is
3. Which method — and why this one?
Sharing, not transferring, is covalent.
4. Step-by-step working
01 / 07
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 07
Step B — Write the given in a column
A bond between two non-metals that share electrons is
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
03 / 07
Step C — Name the method in words
Sharing, not transferring, is covalent.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
04 / 07
Working
Sharing, not transferring, is covalent.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
05 / 07
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
06 / 07
Step F — Box the answer with its unit
covalent
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
07 / 07
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
covalent
Copy onto your answer sheet — in this order
Answer: covalent
6. Check it like a marker
Sharing, not transferring, is covalent.
7. A trap first-timers fall into
ionic
3.2 · 8 Marks · Energy and chemical change
In an energy profile, the activation energy is
Energy and chemical change
Formulas
ΔH < 0exothermicΔH > 0endothermic
Sign of enthalpy change
Notes: In an energy profile, the activation energy is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: In an energy profile, the activation energy is
In other words — as if you have never seen this before
E_a is the hill. ΔH is products minus reactants.
2. What do we already know?
In an energy profile, the activation energy is
3. Which method — and why this one?
E_a is the hill. ΔH is products minus reactants.
4. Step-by-step working
01 / 07
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 07
Step B — Write the given in a column
In an energy profile, the activation energy is
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
03 / 07
Step C — Name the method in words
E_a is the hill. ΔH is products minus reactants.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
04 / 07
Working
E_a is the hill. ΔH is products minus reactants.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
05 / 07
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
06 / 07
Step F — Box the answer with its unit
the energy from reactants up to the peak
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
07 / 07
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
the energy from reactants up to the peak
Copy onto your answer sheet — in this order
Answer: the energy from reactants up to the peak
6. Check it like a marker
E_a is the hill. ΔH is products minus reactants.
7. A trap first-timers fall into
ΔH
7 · 3 Marks
A reaction with ΔH = +180 kJ·mol⁻¹ is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A reaction with ΔH = +180 kJ·mol⁻¹ is
Before any working — hunt first
Given
Numbers and units already in the sentence: 180 kJ·mol⁻¹. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: A reaction with ΔH = +180 kJ·mol⁻¹ is. Circle that word — that is the missing variable.
Find
We are required to find: A reaction with ΔH = +180 kJ·mol⁻¹ is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: endothermic. Then substitute the given, one line at a time, to get A reaction with ΔH = +180 kJ·mol⁻¹ is.
In other words — as if you have never seen this before
endothermic
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 180 kJ·mol⁻¹. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
endothermic
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 180 kJ·mol⁻¹. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: A reaction with ΔH = +180 kJ·mol⁻¹ is. Circle that word — that is the missing variable.
Find: We are required to find: A reaction with ΔH = +180 kJ·mol⁻¹ is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: endothermic. Then substitute the given, one line at a time, to get A reaction with ΔH = +180 kJ·mol⁻¹ is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 180 kJ·mol⁻¹. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
endothermic
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
Positive ΔH: the system absorbed heat.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
endothermic
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
endothermic
Copy onto your answer sheet — in this order
Answer: endothermic
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
8 · 2 Marks
23.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Durban lab. 1:1. c(NaOH) =
Notes: 23.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Durban lab. 1:1. c(NaOH) =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 23.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Durban lab. 1:1. c(NaOH) =
Before any working — hunt first
Given
Numbers and units already in the sentence: 23.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find
We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
In other words — as if you have never seen this before
n(HCl)=0.100×0.023. c=n0.025=0.092 mol·dm⁻³.
2. What do we already know?
23.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Durban lab. 1:1. c(NaOH) =
3. Which method — and why this one?
n(HCl)=0.100×0.023. c=n0.025=0.092 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 23.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find: We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
23.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Durban lab. 1:1. c(NaOH) =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
n(HCl)=0.100×0.023. c=n0.025=0.092 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
n(HCl)=0.100×0.023. c=n0.025=0.092 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.092 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Ideal gas: n = 1.0 mol, T = 300 K, p = 100 kPa, R = 8.3. V =
Before any working — hunt first
Given
Numbers and units already in the sentence: 1.0 mol · 300 K · 100 kPa · 8.3. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: V =. Circle that word — that is the missing variable.
Find
We are required to find: V =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 24. Then substitute the given, one line at a time, to get V =.
In other words — as if you have never seen this before
24.9 dm³
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 1.0 mol · 300 K · 100 kPa · 8.3. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
24.9 dm³
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 1.0 mol · 300 K · 100 kPa · 8.3. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: V =. Circle that word — that is the missing variable.
Find: We are required to find: V =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 24. Then substitute the given, one line at a time, to get V =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 1.0 mol · 300 K · 100 kPa · 8.3. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
24.9 dm³
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
V=nRTp=1×8.3×300100=24.9 dm³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
24.9 dm³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
24.9 dm³
Copy onto your answer sheet — in this order
Answer: 24.9 dm³
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
10 · 2 Marks
25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Polokwane lab. 1:1. c(NaOH) =
Notes: 25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Polokwane lab. 1:1. c(NaOH) =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Polokwane lab. 1:1. c(NaOH) =
Before any working — hunt first
Given
Numbers and units already in the sentence: 25.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find
We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
In other words — as if you have never seen this before
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
2. What do we already know?
25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Polokwane lab. 1:1. c(NaOH) =
3. Which method — and why this one?
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 25.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find: We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Polokwane lab. 1:1. c(NaOH) =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.1 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.1 mol·dm⁻³
Copy onto your answer sheet — in this order
Answer: 0.1 mol·dm⁻³
6. Check it like a marker
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
7. A trap first-timers fall into
0.140 mol·dm⁻³
11 · 2 Marks
ΔEN for Na 0.9 and Cl 3.0 is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: ΔEN for Na 0.9 and Cl 3.0 is
Before any working — hunt first
Given
Numbers and units already in the sentence: 0.9 and · 3.0 is. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: 0 is. Circle that word — that is the missing variable.
Find
We are required to find: 0 is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 2. Then substitute the given, one line at a time, to get 0 is.
In other words — as if you have never seen this before
2.1
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 0.9 and · 3.0 is. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
2.1
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 0.9 and · 3.0 is. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 0 is. Circle that word — that is the missing variable.
Find: We are required to find: 0 is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 2. Then substitute the given, one line at a time, to get 0 is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 0.9 and · 3.0 is. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
2.1
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
3.0−0.9=2.1 > 1.7→ionic.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
2.1
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
2.1
Copy onto your answer sheet — in this order
Answer: 2.1
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
12 · 2 Marks
24.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Gqeberha lab. 1:1. c(NaOH) =
Notes: 24.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Gqeberha lab. 1:1. c(NaOH) =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 24.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Gqeberha lab. 1:1. c(NaOH) =
Before any working — hunt first
Given
Numbers and units already in the sentence: 24.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find
We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
In other words — as if you have never seen this before
n(HCl)=0.100×0.024. c=n0.025=0.096 mol·dm⁻³.
2. What do we already know?
24.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Gqeberha lab. 1:1. c(NaOH) =
3. Which method — and why this one?
n(HCl)=0.100×0.024. c=n0.025=0.096 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 24.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find: We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
24.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Gqeberha lab. 1:1. c(NaOH) =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
n(HCl)=0.100×0.024. c=n0.025=0.096 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
n(HCl)=0.100×0.024. c=n0.025=0.096 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.096 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.096 mol·dm⁻³
Copy onto your answer sheet — in this order
Answer: 0.096 mol·dm⁻³
6. Check it like a marker
n(HCl)=0.100×0.024. c=n0.025=0.096 mol·dm⁻³.
7. A trap first-timers fall into
0.136 mol·dm⁻³
13 · 2 Marks
NaCl is held by
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: NaCl is held by
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: NaCl is held by. Circle that word — that is the missing variable.
Find
We are required to find: NaCl is held by. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: Metal + non-metal: electrons are transferred. Then substitute the given, one line at a time, to get NaCl is held by.
In other words — as if you have never seen this before
Metal + non-metal: electrons are transferred. Na⁺ Cl⁻ lattice.
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
Metal + non-metal: electrons are transferred. Na⁺ Cl⁻ lattice.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: NaCl is held by. Circle that word — that is the missing variable.
Find: We are required to find: NaCl is held by. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: Metal + non-metal: electrons are transferred. Then substitute the given, one line at a time, to get NaCl is held by.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
Metal + non-metal: electrons are transferred. Na⁺ Cl⁻ lattice.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
Metal + non-metal: electrons are transferred. Na⁺ Cl⁻ lattice.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
ionic bonds
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
ionic bonds
Copy onto your answer sheet — in this order
Answer: ionic bonds
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
14 · 2 Marks · Energy and chemical change
Activation energy is
Energy and chemical change
Formulas
ΔH < 0exothermicΔH > 0endothermic
Sign of enthalpy change
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Activation energy is
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Activation energy is. Circle that word — that is the missing variable.
Find
We are required to find: Activation energy is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: the minimum energy to start. Then substitute the given, one line at a time, to get Activation energy is.
In other words — as if you have never seen this before
the minimum energy to start
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
the minimum energy to start
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Activation energy is. Circle that word — that is the missing variable.
Find: We are required to find: Activation energy is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: the minimum energy to start. Then substitute the given, one line at a time, to get Activation energy is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
the minimum energy to start
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
It is the hill the particles must climb, not the overall ΔH.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
the minimum energy needed to start the reaction
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
the minimum energy needed to start the reaction
Copy onto your answer sheet — in this order
Answer: the minimum energy needed to start the reaction
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
15 · 2 Marks
pH of 0.010 mol·dm⁻³ HCl is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: pH of 0.010 mol·dm⁻³ HCl is
Before any working — hunt first
Given
Numbers and units already in the sentence: 0.010 mol·dm⁻³. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: 010 mol·dm⁻³ HCl is. Circle that word — that is the missing variable.
Find
We are required to find: 010 mol·dm⁻³ HCl is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 2. Then substitute the given, one line at a time, to get 010 mol·dm⁻³ HCl is.
In other words — as if you have never seen this before
2
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 0.010 mol·dm⁻³. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
2
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 0.010 mol·dm⁻³. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 010 mol·dm⁻³ HCl is. Circle that word — that is the missing variable.
Find: We are required to find: 010 mol·dm⁻³ HCl is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 2. Then substitute the given, one line at a time, to get 010 mol·dm⁻³ HCl is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 0.010 mol·dm⁻³. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
2
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
Strong acid: [H₃O⁺]=0.010=10⁻². pH=2.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
2
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
2
Copy onto your answer sheet — in this order
Answer: 2
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
16 · 2 Marks
Theoretical yield 10 g. Actual yield 8 g. Percentage yield =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Theoretical yield 10 g. Actual yield 8 g. Percentage yield =
Before any working — hunt first
Given
Numbers and units already in the sentence: 10 g · 8 g. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Percentage yield =. Circle that word — that is the missing variable.
Find
We are required to find: Percentage yield =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 80%. Then substitute the given, one line at a time, to get Percentage yield =.
In other words — as if you have never seen this before
80%
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 10 g · 8 g. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
80%
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 10 g · 8 g. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Percentage yield =. Circle that word — that is the missing variable.
Find: We are required to find: Percentage yield =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 80%. Then substitute the given, one line at a time, to get Percentage yield =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 10 g · 8 g. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
80%
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
(8/10)×100=80%.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
80%
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
80%
Copy onto your answer sheet — in this order
Answer: 80%
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
17 · 2 Marks
At constant temperature, if the pressure of a gas doubles, the volume
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: At constant temperature, if the pressure of a gas doubles, the volume
In other words — as if you have never seen this before
is halved
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
is halved
4. Step-by-step working
01 / 07
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 07
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
03 / 07
Step C — Name the method in words
is halved
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
04 / 07
Reason
Boyle: pV is constant. Double p means half V.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
05 / 07
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
06 / 07
Step F — Box the answer with its unit
is halved
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
07 / 07
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
is halved
Copy onto your answer sheet — in this order
Answer: is halved
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
18 · 2 Marks
c = nV. n = 0.05 mol in 0.25 dm³. c =
Notes: c = nV. n = 0.05 mol in 0.25 dm³. c =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: c = nV. n = 0.05 mol in 0.25 dm³. c =
Before any working — hunt first
Given
Numbers and units already in the sentence: 0.05 mol · 0.25 dm³. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c =. Circle that word — that is the missing variable.
Find
We are required to find: c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: c = 0. Then substitute the given, one line at a time, to get c =.
In other words — as if you have never seen this before
c=0.050.25=0.2 mol·dm⁻³.
2. What do we already know?
c = nV. n = 0.05 mol in 0.25 dm³. c =
3. Which method — and why this one?
c=0.050.25=0.2 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 0.05 mol · 0.25 dm³. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c =. Circle that word — that is the missing variable.
Find: We are required to find: c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: c = 0. Then substitute the given, one line at a time, to get c =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
c = nV. n = 0.05 mol in 0.25 dm³. c =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
c=0.050.25=0.2 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
c=0.050.25=0.2 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.2 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.2 mol·dm⁻³
Copy onto your answer sheet — in this order
Answer: 0.2 mol·dm⁻³
6. Check it like a marker
c=0.050.25=0.2 mol·dm⁻³.
7. A trap first-timers fall into
0.013 mol·dm⁻³
19 · 2 Marks
22.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Mbombela lab. 1:1. c(NaOH) =
Notes: 22.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Mbombela lab. 1:1. c(NaOH) =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 22.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Mbombela lab. 1:1. c(NaOH) =
Before any working — hunt first
Given
Numbers and units already in the sentence: 22.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find
We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
In other words — as if you have never seen this before
n(HCl)=0.100×0.022. c=n0.025=0.088 mol·dm⁻³.
2. What do we already know?
22.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Mbombela lab. 1:1. c(NaOH) =
3. Which method — and why this one?
n(HCl)=0.100×0.022. c=n0.025=0.088 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 22.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find: We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
22.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Mbombela lab. 1:1. c(NaOH) =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
n(HCl)=0.100×0.022. c=n0.025=0.088 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
n(HCl)=0.100×0.022. c=n0.025=0.088 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.088 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.088 mol·dm⁻³
Copy onto your answer sheet — in this order
Answer: 0.088 mol·dm⁻³
6. Check it like a marker
n(HCl)=0.100×0.022. c=n0.025=0.088 mol·dm⁻³.
7. A trap first-timers fall into
0.128 mol·dm⁻³
20 · 2 Marks
25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Cape Town lab. 1:1. c(NaOH) =
Notes: 25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Cape Town lab. 1:1. c(NaOH) =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Cape Town lab. 1:1. c(NaOH) =
Before any working — hunt first
Given
Numbers and units already in the sentence: 25.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find
We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
In other words — as if you have never seen this before
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
2. What do we already know?
25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Cape Town lab. 1:1. c(NaOH) =
3. Which method — and why this one?
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 25.0 cm³ · 0.100 mol·dm⁻³ · 25.0 cm³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c(NaOH) =. Circle that word — that is the missing variable.
Find: We are required to find: c(NaOH) =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: n(HCl) = 0. Then substitute the given, one line at a time, to get c(NaOH) =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
25.0 cm³ of 0.100 mol·dm⁻³ HCl neutralises 25.0 cm³ NaOH in a Cape Town lab. 1:1. c(NaOH) =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.1 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.1 mol·dm⁻³
Copy onto your answer sheet — in this order
Answer: 0.1 mol·dm⁻³
6. Check it like a marker
n(HCl)=0.100×0.025. c=n0.025=0.1 mol·dm⁻³.
7. A trap first-timers fall into
0.140 mol·dm⁻³
21 · 2 Marks
Molar volume at STP is 22.4 dm³·mol⁻¹. Volume of 0.50 mol of gas?
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Molar volume at STP is 22.4 dm³·mol⁻¹. Volume of 0.50 mol of gas?
Before any working — hunt first
Given
Numbers and units already in the sentence: 22.4 dm³·mol⁻¹ · 0.50 mol. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: 50 mol of gas. Circle that word — that is the missing variable.
Find
We are required to find: 50 mol of gas. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 11. Then substitute the given, one line at a time, to get 50 mol of gas.
In other words — as if you have never seen this before
11.2 dm³
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 22.4 dm³·mol⁻¹ · 0.50 mol. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
11.2 dm³
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 22.4 dm³·mol⁻¹ · 0.50 mol. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: 50 mol of gas. Circle that word — that is the missing variable.
Find: We are required to find: 50 mol of gas. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 11. Then substitute the given, one line at a time, to get 50 mol of gas.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 22.4 dm³·mol⁻¹ · 0.50 mol. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
11.2 dm³
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
0.50×22.4=11.2 dm³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
11.2 dm³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
11.2 dm³
Copy onto your answer sheet — in this order
Answer: 11.2 dm³
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
22 · 2 Marks
A reaction that feels cold and has ΔH > 0 is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: A reaction that feels cold and has ΔH > 0 is
In other words — as if you have never seen this before
endothermic
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 0 is. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
endothermic
4. Step-by-step working
01 / 07
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 07
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 0 is. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
03 / 07
Step C — Name the method in words
endothermic
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
04 / 07
Reason
The system takes heat in. ΔH is positive.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
05 / 07
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
06 / 07
Step F — Box the answer with its unit
endothermic
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
07 / 07
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
endothermic
Copy onto your answer sheet — in this order
Answer: endothermic
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
23 · 2 Marks
20.0 cm³ of 0.10 mol·dm⁻³ HCl needs how much 0.20 mol·dm⁻³ NaOH? (1:1)
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 20.0 cm³ of 0.10 mol·dm⁻³ HCl needs how much 0.20 mol·dm⁻³ NaOH? (1:1)
Before any working — hunt first
Given
Numbers and units already in the sentence: 20.0 cm³ · 0.10 mol·dm⁻³ · 0.20 mol·dm⁻³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: how much 0. Circle that word — that is the missing variable.
Find
We are required to find: how much 0. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: 10. Then substitute the given, one line at a time, to get how much 0.
In other words — as if you have never seen this before
10.0 cm³
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 20.0 cm³ · 0.10 mol·dm⁻³ · 0.20 mol·dm⁻³ · 1 · 1. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
10.0 cm³
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 20.0 cm³ · 0.10 mol·dm⁻³ · 0.20 mol·dm⁻³ · 1 · 1. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: how much 0. Circle that word — that is the missing variable.
Find: We are required to find: how much 0. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: 10. Then substitute the given, one line at a time, to get how much 0.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 20.0 cm³ · 0.10 mol·dm⁻³ · 0.20 mol·dm⁻³ · 1 · 1. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
10.0 cm³
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
10.0 cm³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
10.0 cm³
Copy onto your answer sheet — in this order
Answer: 10.0 cm³
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
24 · 2 Marks
The shape of H₂O is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: The shape of H₂O is
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: The shape of H₂O is. Circle that word — that is the missing variable.
Find
We are required to find: The shape of H₂O is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: bent. Then substitute the given, one line at a time, to get The shape of H₂O is.
In other words — as if you have never seen this before
bent
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
bent
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: The shape of H₂O is. Circle that word — that is the missing variable.
Find: We are required to find: The shape of H₂O is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: bent. Then substitute the given, one line at a time, to get The shape of H₂O is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
bent
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
Two bond pairs and two lone pairs. Lone pairs push the bonds together.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
bent
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
bent
Copy onto your answer sheet — in this order
Answer: bent
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
25 · 2 Marks
c = nV. n = 0.02 mol in 0.25 dm³. c =
Notes: c = nV. n = 0.02 mol in 0.25 dm³. c =
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: c = nV. n = 0.02 mol in 0.25 dm³. c =
Before any working — hunt first
Given
Numbers and units already in the sentence: 0.02 mol · 0.25 dm³. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: c =. Circle that word — that is the missing variable.
Find
We are required to find: c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: c = 0. Then substitute the given, one line at a time, to get c =.
In other words — as if you have never seen this before
c=0.020.25=0.08 mol·dm⁻³.
2. What do we already know?
c = nV. n = 0.02 mol in 0.25 dm³. c =
3. Which method — and why this one?
c=0.020.25=0.08 mol·dm⁻³.
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 0.02 mol · 0.25 dm³. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: c =. Circle that word — that is the missing variable.
Find: We are required to find: c =. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: c = 0. Then substitute the given, one line at a time, to get c =.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
c = nV. n = 0.02 mol in 0.25 dm³. c =
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
c=0.020.25=0.08 mol·dm⁻³.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Working
c=0.020.25=0.08 mol·dm⁻³.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
0.08 mol·dm⁻³
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
0.08 mol·dm⁻³
Copy onto your answer sheet — in this order
Answer: 0.08 mol·dm⁻³
6. Check it like a marker
c=0.020.25=0.08 mol·dm⁻³.
7. A trap first-timers fall into
0.005 mol·dm⁻³
26 · 2 Marks
HCl(aq) + NaOH(aq) →
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: HCl(aq) + NaOH(aq) →
Before any working — hunt first
Given
Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: HCl(aq) + NaOH(aq) →. Circle that word — that is the missing variable.
Find
We are required to find: HCl(aq) + NaOH(aq) →. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: NaCl(aq) + H₂O(l). Then substitute the given, one line at a time, to get HCl(aq) + NaOH(aq) →.
In other words — as if you have never seen this before
NaCl(aq) + H₂O(l)
2. What do we already know?
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
NaCl(aq) + H₂O(l)
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: no numbers yet — only a name, a diagram, or a worded unknown. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: HCl(aq) + NaOH(aq) →. Circle that word — that is the missing variable.
Find: We are required to find: HCl(aq) + NaOH(aq) →. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: NaCl(aq) + H₂O(l). Then substitute the given, one line at a time, to get HCl(aq) + NaOH(aq) →.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: every number and its unit in the sentence. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
NaCl(aq) + H₂O(l)
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
Acid plus base gives a salt and water.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
NaCl(aq) + H₂O(l)
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
NaCl(aq) + H₂O(l)
Copy onto your answer sheet — in this order
Answer: NaCl(aq) + H₂O(l)
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
27 · 2 Marks
2H₂ + O₂ → 2H₂O. 2 mol H₂ is mixed with 2 mol O₂. The limiting reagent is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 2H₂ + O₂ → 2H₂O. 2 mol H₂ is mixed with 2 mol O₂. The limiting reagent is
Before any working — hunt first
Given
Numbers and units already in the sentence: 2H · 2H · 2 mol · 2 mol. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: The limiting reagent is. Circle that word — that is the missing variable.
Find
We are required to find: The limiting reagent is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: H₂. Then substitute the given, one line at a time, to get The limiting reagent is.
In other words — as if you have never seen this before
H₂
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 2H · 2H · 2 mol · 2 mol. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
H₂
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 2H · 2H · 2 mol · 2 mol. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: The limiting reagent is. Circle that word — that is the missing variable.
Find: We are required to find: The limiting reagent is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: H₂. Then substitute the given, one line at a time, to get The limiting reagent is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 2H · 2H · 2 mol · 2 mol. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
H₂
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
The ratio needs 2 mol H₂ per 1 mol O₂. 2 mol O₂ is excess.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
H₂
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
H₂
Copy onto your answer sheet — in this order
Answer: H₂
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
28 · 2 Marks
ΔH = −210 kJ·mol⁻¹ means the reaction is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: ΔH = −210 kJ·mol⁻¹ means the reaction is
Before any working — hunt first
Given
Numbers and units already in the sentence: 210 kJ·mol⁻¹. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: ΔH = −210 kJ·mol⁻¹ means the reaction is. Circle that word — that is the missing variable.
Find
We are required to find: ΔH = −210 kJ·mol⁻¹ means the reaction is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: exothermic. Then substitute the given, one line at a time, to get ΔH = −210 kJ·mol⁻¹ means the reaction is.
In other words — as if you have never seen this before
exothermic
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 210 kJ·mol⁻¹. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
exothermic
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 210 kJ·mol⁻¹. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: ΔH = −210 kJ·mol⁻¹ means the reaction is. Circle that word — that is the missing variable.
Find: We are required to find: ΔH = −210 kJ·mol⁻¹ means the reaction is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: exothermic. Then substitute the given, one line at a time, to get ΔH = −210 kJ·mol⁻¹ means the reaction is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 210 kJ·mol⁻¹. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
exothermic
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
Negative ΔH: the system released heat.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
exothermic
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
exothermic
Copy onto your answer sheet — in this order
Answer: exothermic
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
29 · 2 Marks
Zn → Zn²⁺ + 2e⁻ is
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Zn → Zn²⁺ + 2e⁻ is
Before any working — hunt first
Given
Numbers and units already in the sentence: 2e⁻. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Zn → Zn²⁺ + 2e⁻ is. Circle that word — that is the missing variable.
Find
We are required to find: Zn → Zn²⁺ + 2e⁻ is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: oxidation. Then substitute the given, one line at a time, to get Zn → Zn²⁺ + 2e⁻ is.
In other words — as if you have never seen this before
oxidation
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 2e⁻. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
oxidation
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 2e⁻. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Zn → Zn²⁺ + 2e⁻ is. Circle that word — that is the missing variable.
Find: We are required to find: Zn → Zn²⁺ + 2e⁻ is. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: oxidation. Then substitute the given, one line at a time, to get Zn → Zn²⁺ + 2e⁻ is.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 2e⁻. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
oxidation
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
05 / 08
Reason
Zinc loses two electrons.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
oxidation
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
oxidation
Copy onto your answer sheet — in this order
Answer: oxidation
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”
30 · 2 Marks
40% C, 6.7% H, 53.3% O by mass. Empirical formula?
How we got there
Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.
Explain in another language · 11
1. What is the question asking?
Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: 40% C, 6.7% H, 53.3% O by mass. Empirical formula?
Before any working — hunt first
Given
Numbers and units already in the sentence: 40% · 6.7% · 53.3%. Copy each one into a column. A name without a number is not given.
Missing
After you copy the given, the letter that still has no number is missing. The paper is pointing at: Empirical formula. Circle that word — that is the missing variable.
Find
We are required to find: Empirical formula. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate
What we need to calculate: CH₂O. Then substitute the given, one line at a time, to get Empirical formula.
In other words — as if you have never seen this before
CH₂O
2. What do we already know?
Copy these onto the left of your page, one per line, with units: 40% · 6.7% · 53.3%. Mixing cm with m, or minutes with seconds, loses a method mark.
3. Which method — and why this one?
CH₂O
4. Step-by-step working
01 / 08
Step A — Read the question twice
Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
02 / 08
Step A2 — Hunt: Given, Missing, Find, Calculate
Given: Numbers and units already in the sentence: 40% · 6.7% · 53.3%. Copy each one into a column. A name without a number is not given.
Missing: After you copy the given, the letter that still has no number is missing. The paper is pointing at: Empirical formula. Circle that word — that is the missing variable.
Find: We are required to find: Empirical formula. Write that as a symbol on the left, with a question mark, before you touch a formula.
Calculate: What we need to calculate: CH₂O. Then substitute the given, one line at a time, to get Empirical formula.
Why this step: Do not name the letters yet. First hunt: what already has a number (Given), what has no number (Missing), the word the paper wants (Find), and which formula still contains the missing letter (Calculate).
03 / 08
Step B — Write the given in a column
Copy these onto the left of your page, one per line, with units: 40% · 6.7% · 53.3%. Mixing cm with m, or minutes with seconds, loses a method mark.
Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.
04 / 08
Step C — Name the method in words
CH₂O
Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.
Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.
06 / 08
Step G — Sense-check the size
Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.
Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.
07 / 08
Step F — Box the answer with its unit
CH₂O
Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.
08 / 08
Step H — What the marker is looking for
On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.
Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.
5. The answer
CH₂O
Copy onto your answer sheet — in this order
Answer: CH₂O
6. Check it like a marker
Does your answer appear as one of the options? Do the units match what was asked (m, N, J, °)? If you put the number back into the original equation, does it still hold? Estimate: is the size sensible?
7. A trap first-timers fall into
First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”