£1
Topic 1
A Level Chemistry Examiners' Edition: Common Mistakes by Topic (Edexcel) | GuideMyGrades
Examiners’ Edition · Edexcel A Level Chemistry
Aiming for an A or A*? Stop losing easy marks.
Most marks aren’t lost on the hardest questions. They’re lost to the same small mistakes examiners flag year after year. We’ve gone through the Pearson Edexcel AS and A Level Chemistry papers and examiners’ reports and pulled out the mistakes that cost the most marks in every topic.
- See the mistake examiners flag year after year, topic by topic.
- Learn the fix, and what examiners saw in the exam.
- Practise and mark it with original questions and full mark schemes.
A Level Chemistry · Topic 12
Acid-Base Equilibria
Examiners’ Edition: Securing A*s
12.1 Brønsted-Lowry acids and bases A Level only
1 Acid and base definitions
✗ Common mistake
Calling a base a proton donor, giving the Lewis definition (“electron pair acceptor”), or writing a definition when the question asks something else.
1
✓ Do this instead
Brønsted-Lowry acid: a proton (H+) donor. Brønsted-Lowry base: a proton (H+) acceptor. Lewis definitions (electron pairs) are not credited when a Brønsted-Lowry answer is asked for.
2
In the exam
“A few defined a base as a proton donor, which is the definition of an acid.” Jun 2022, AL P1
Examiners flagged this in 3 exam series, 2019 to 2024
Question 1.1 · Check itMark scheme ›3
State what is meant by a Brønsted-Lowry acid and by a Brønsted-Lowry base. (2)
Mark scheme · Q1.1‹ Back to question
Acid: proton (H+) donor1
Base: proton (H+) acceptor1
Common wrong answers: “A base is a proton donor”; “electron pair acceptor”.
- Topics
- 19
- Common mistakes fixed
- 225
- Practice questions
- 450
- Per topic, one-off
- £1
- 1
Add topics to your basketPick one, or every topic you’re revising.
- 2
Pay once by cardSecure checkout with Stripe. No account, no subscription.
- 3
Download straight awayYour PDFs open after payment, and the link is emailed to you. Each PDF can be downloaded up to 10 times.
Pearson Edexcel AS & A Level Chemistry · 8CH0, 9CH0
Choose your topics
£1 each. Add as many as you like and pay once.
Free sample
Not sure yet? See exactly what you get before you buy.
AS & A Level
Topics 1 to 10
Assessed on both the AS and the A Level papers.
£1
Topic 2
Bonding and Structure
£1
Topic 3
Redox I
£1
Topic 4
Inorganic Chemistry and the Periodic Table
£1
Topic 5
Formulae, Equations and Amounts of Substance
£1
Topic 6
Organic Chemistry I
£1
Topic 7
Modern Analytical Techniques I
£1
Topic 8
Energetics I
£1
Topic 9
Kinetics I
£1
Topic 10
Equilibrium I
A Level only
Topics 11 to 19
Assessed on the A Level papers only.
£1
Topic 11
Equilibrium II
£1
Topic 12
Acid-Base Equilibria
£1
Topic 13
Energetics II
£1
Topic 14
Redox II
£1
Topic 15
Transition Metals
£1
Topic 16
Kinetics II
£1
Topic 17
Organic Chemistry II
£1
Topic 18
Organic Chemistry III
£1
Topic 19
Modern Analytical Techniques II
GuideMyGrades is independent and is not affiliated with or endorsed by Pearson. All practice questions are original. Each PDF is for the buyer’s own study. Questions about a purchase? Email info@guidemygrades.com.
Want the free booklets too?
Our Chemistry Questions by Topic booklets are free, always, with the mark scheme built into every one, for A-Level, IGCSE, GCSE and Combined Science.
Free Questions by TopicTaking IGCSE or GCSE Chemistry? IGCSE & GCSE Chemistry Examiners’ Edition, £1 per topic.