AQA A-LEVEL
CHEMISTRY
AQA Chemistry
A-level Questions
That Seem Easy But Tricky
and How to Answer Them
Stop losing marks on questions you already know
Equilibrium Rates Titrations Enthalpy Organic Bonding
Complete Topic Coverage
Exam-focused | Clear Explanations | Common Mistakes Revealed ⚗
,AQA Chemistry A-level — Questions That Seem Easy But Tricky Page 1
INTRODUCTION — HOW TO USE THIS GUIDE
Who is this guide for?
This guide is for anyone studying AQA A-level Chemistry who wants to stop losing
marks on questions they already understand. You will recognise every topic here. The
problem is not your knowledge — it is the way the question is phrased and the habits
that lead to a wrong answer even when you know the right one.
What is the difference between a hard question and a tricky
one?
A hard question tests material you have not seen before. A tricky question tests
something you know, but uses wording or context that triggers a common mistake.
AQA papers are full of tricky questions. Examiners design them that way deliberately
— to separate students who understand deeply from students who have only
memorised surface facts.
How each chapter is structured
Every chapter in this guide follows the same format. First, you get a short explanation
of why the topic is tricky. Then you see the trap — the specific mistake students make.
Then an exam-style question, a model answer, key tips, a summary table, a practice
question with a worked solution, and a note on what examiners look for. This structure
is deliberate: you learn the trap before you see the answer, which is more effective
than reading answers first.
How to use this guide effectively
Do not read this like a textbook. Read each chapter once, cover the model answer,
and write your own answer to the exam question. Then compare. If your answer
matches the model, move on. If it does not, read the tips again and redo the practice
question. Repeat any chapter where you make the described trap. One hour with this
guide, done actively, is worth more than five hours of passive reading.
A note on language
The answers in this guide use the same language that AQA mark schemes use. You do
not need to memorise phrases word for word, but you do need to include the key
ideas. In chemistry, being vague costs marks. Saying 'the equilibrium shifts' is not
enough — you need to say which direction and why. That level of precision is what this
guide trains.
Master the Tricky Parts · Think Carefully · Check Your Answer
,AQA Chemistry A-level — Questions That Seem Easy But Tricky Page 2
QUICK REFERENCE — THE 12 TRAPS IN 60 SECONDS
Chapter Topic The trap in one sentence
K only changes with temperature — not
01 Equilibrium
pressure or concentration.
Second electron affinity is always
02 Born-Haber
endothermic (positive).
Name the species and write the equation —
03 Buffers
do not just describe.
Orders come from experimental data, never
04 Rate orders
from the equation.
Primary = SN2 (no carbocation). Tertiary =
05 SN1 / SN2
SN1.
Count lone pairs too — each one compresses
06 VSEPR / shapes
the angle by ~2.5°.
E°cell = E°cathode − E°anode. Cathode is
07 Cell EMF
the more positive half-cell.
Arrow tail from bond or lone pair — never
08 Curly arrows
from a δ+ symbol.
Convert ΔS from J to kJ before using ΔG = ΔH
09 Gibbs / ΔG
− TΔS.
Divide cm³ by 1000 to get dm³ before using
10 Titrations
n = c × V.
IE1 drops at Group 13 (3p higher than 3s)
11 Ionisation energy
and Group 16 (pairing).
All 12 traps in one table — use as a
12 Recap
pre-exam checklist.
Master the Tricky Parts · Think Carefully · Check Your Answer
, AQA Chemistry A-level — Questions That Seem Easy But Tricky Page 3
TABLE OF CONTENTS
01. Equilibrium — Le Chatelier's Principle
02. Enthalpy — Born-Haber Cycles
03. Acid-Base — Buffer Solutions
04. Reaction Rates — Orders and Rate Equations
05. Organic — Nucleophilic Substitution (SN1 vs SN2)
06. Bonding — Shapes and Bond Angles
07. Electrochemistry — Cell EMF and Electrode Potentials
08. Organic Mechanisms — Curly Arrow Errors
09. Thermodynamics — Entropy and Gibbs Free Energy
10. Titration Calculations — Common Unit Traps
11. Periodicity — Ionisation Energy Trends
12. Quick Recap — The 12 Traps at a Glance
This guide covers twelve topic areas in AQA A-level Chemistry where students
regularly lose marks — not because they do not understand the topic, but because the
question is worded in a way that triggers a well-known mistake. Each chapter gives
you: the trap, a real-style exam question, a model answer, key tips, and a summary
table. Read each chapter twice — once to understand, once to memorise the fix.
Master the Tricky Parts · Think Carefully · Check Your Answer
CHEMISTRY
AQA Chemistry
A-level Questions
That Seem Easy But Tricky
and How to Answer Them
Stop losing marks on questions you already know
Equilibrium Rates Titrations Enthalpy Organic Bonding
Complete Topic Coverage
Exam-focused | Clear Explanations | Common Mistakes Revealed ⚗
,AQA Chemistry A-level — Questions That Seem Easy But Tricky Page 1
INTRODUCTION — HOW TO USE THIS GUIDE
Who is this guide for?
This guide is for anyone studying AQA A-level Chemistry who wants to stop losing
marks on questions they already understand. You will recognise every topic here. The
problem is not your knowledge — it is the way the question is phrased and the habits
that lead to a wrong answer even when you know the right one.
What is the difference between a hard question and a tricky
one?
A hard question tests material you have not seen before. A tricky question tests
something you know, but uses wording or context that triggers a common mistake.
AQA papers are full of tricky questions. Examiners design them that way deliberately
— to separate students who understand deeply from students who have only
memorised surface facts.
How each chapter is structured
Every chapter in this guide follows the same format. First, you get a short explanation
of why the topic is tricky. Then you see the trap — the specific mistake students make.
Then an exam-style question, a model answer, key tips, a summary table, a practice
question with a worked solution, and a note on what examiners look for. This structure
is deliberate: you learn the trap before you see the answer, which is more effective
than reading answers first.
How to use this guide effectively
Do not read this like a textbook. Read each chapter once, cover the model answer,
and write your own answer to the exam question. Then compare. If your answer
matches the model, move on. If it does not, read the tips again and redo the practice
question. Repeat any chapter where you make the described trap. One hour with this
guide, done actively, is worth more than five hours of passive reading.
A note on language
The answers in this guide use the same language that AQA mark schemes use. You do
not need to memorise phrases word for word, but you do need to include the key
ideas. In chemistry, being vague costs marks. Saying 'the equilibrium shifts' is not
enough — you need to say which direction and why. That level of precision is what this
guide trains.
Master the Tricky Parts · Think Carefully · Check Your Answer
,AQA Chemistry A-level — Questions That Seem Easy But Tricky Page 2
QUICK REFERENCE — THE 12 TRAPS IN 60 SECONDS
Chapter Topic The trap in one sentence
K only changes with temperature — not
01 Equilibrium
pressure or concentration.
Second electron affinity is always
02 Born-Haber
endothermic (positive).
Name the species and write the equation —
03 Buffers
do not just describe.
Orders come from experimental data, never
04 Rate orders
from the equation.
Primary = SN2 (no carbocation). Tertiary =
05 SN1 / SN2
SN1.
Count lone pairs too — each one compresses
06 VSEPR / shapes
the angle by ~2.5°.
E°cell = E°cathode − E°anode. Cathode is
07 Cell EMF
the more positive half-cell.
Arrow tail from bond or lone pair — never
08 Curly arrows
from a δ+ symbol.
Convert ΔS from J to kJ before using ΔG = ΔH
09 Gibbs / ΔG
− TΔS.
Divide cm³ by 1000 to get dm³ before using
10 Titrations
n = c × V.
IE1 drops at Group 13 (3p higher than 3s)
11 Ionisation energy
and Group 16 (pairing).
All 12 traps in one table — use as a
12 Recap
pre-exam checklist.
Master the Tricky Parts · Think Carefully · Check Your Answer
, AQA Chemistry A-level — Questions That Seem Easy But Tricky Page 3
TABLE OF CONTENTS
01. Equilibrium — Le Chatelier's Principle
02. Enthalpy — Born-Haber Cycles
03. Acid-Base — Buffer Solutions
04. Reaction Rates — Orders and Rate Equations
05. Organic — Nucleophilic Substitution (SN1 vs SN2)
06. Bonding — Shapes and Bond Angles
07. Electrochemistry — Cell EMF and Electrode Potentials
08. Organic Mechanisms — Curly Arrow Errors
09. Thermodynamics — Entropy and Gibbs Free Energy
10. Titration Calculations — Common Unit Traps
11. Periodicity — Ionisation Energy Trends
12. Quick Recap — The 12 Traps at a Glance
This guide covers twelve topic areas in AQA A-level Chemistry where students
regularly lose marks — not because they do not understand the topic, but because the
question is worded in a way that triggers a well-known mistake. Each chapter gives
you: the trap, a real-style exam question, a model answer, key tips, and a summary
table. Read each chapter twice — once to understand, once to memorise the fix.
Master the Tricky Parts · Think Carefully · Check Your Answer
