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AP Chemistry Mock: Moles, pH, Titration, Thermodynamics
TUTORZONE ORIGINAL MOCK PAPER · AP CHEMISTRY
Written to the College Board exam format: Section I multiple choice, 60 questions, 1 h 30 min, 50%; Section II free response, 7 questions, 1 h 45 min, 50% (3 long-answer 10 pts + 4 short-answer 4 pts). This paper demonstrates 4 Section II questions with worked answers.
What is in the AP Chemistry exam?
Direct answer: Section I multiple choice, 60 questions, 1 h 30 min, 50%; Section II free response, 7 questions, 1 h 45 min, 50%.
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Section II (Free Response) | 7 questions: 3 long (10 pts) + 4 short (4 pts) | 50% | 1 h 45 min |
| Section I (Multiple Choice) | 60 questions, discrete or question sets | 50% | 1 h 30 min |
In Section II state the formula or law, then substitute, then give the answer with its unit, and explain the principle (e.g. the sign of ΔG for spontaneity).
How this paper was built
This is a TutorZone original mock paper: the questions follow the College Board AP Chemistry format (Section II free response) and the answers are our own computations, not College Board questions or marking references.
Every answer was recomputed programmatically.
Pacing
| Section | Marks | Suggested time | What to do first |
|---|---|---|---|
| Section II (Free Response) | 50% | about 20 min long, 8 min short | state the formula or law first |
| Section I (Multiple Choice) | 50% | about 1.5 min per question | eliminate clearly wrong options |
How is pH calculated?
Direct answer: pH = -log10[H+].
Section II: free response (4 demonstrated)
Demonstrates moles, pH, titration and thermodynamics (ΔG) calculations.
Question 1 (10 marks)
How many moles are in 12 g of sodium hydroxide (NaOH, molar mass 40 g/mol)?
Question 2 (10 marks)
A solution has a hydrogen-ion concentration of 0.001 mol/dm^3. Calculate its pH.
Question 3 (10 marks)
In a titration, 25 cm^3 of 0.1 mol/dm^3 hydrochloric acid is exactly neutralised by 25 cm^3 of sodium hydroxide (1:1). Calculate the sodium hydroxide concentration.
Question 4 (10 marks)
A reaction at 298 K has ΔH = 50 kJ and ΔS = 0.1 kJ/K. Use ΔG = ΔH – TΔS to find the Gibbs free-energy change and state whether the reaction is spontaneous.
How does ΔG indicate spontaneity?
Direct answer: ΔG < 0 spontaneous, ΔG > 0 non-spontaneous, ΔG = 0 at equilibrium.
Answers and marks per question
Question 1
Use n = m/M (4): n = 12 / 40 = 0.3 mol (6).
Question 2
Use pH = -log10[H+] (4): pH = -log10(0.001) = 3 (6).
Question 3
Use c1V1 = c2V2 (4): c2 = 0.1 x 25 / 25 = 0.1 mol/dm^3 (6).
Question 4
ΔG = ΔH – TΔS (4) = 50 – 298 x 0.1 = 20.2 kJ (4); ΔG > 0, so the reaction is non-spontaneous (2).
How is concentration calculated in a titration?
Direct answer: c1V1 = c2V2 (same volume units on both sides).
Where these marks are usually lost
| Mistake | What it looks like | What it costs | Instead |
|---|---|---|---|
| Wrong pH sign | pH = log[H+] | pH is the negative logarithm | pH = -log10[H+] |
| ΔG sign error | ΔG>0 as spontaneous | Only ΔG<0 is spontaneous | ΔG<0 spontaneous, ΔG>0 non-spontaneous |
| Titration units | Unmatched V units | c1V1 = c2V2 needs same units | Use the same volume unit on both sides |
How to use this paper
First sit: all 4 questions with no references.
Mark it: check formula, substitution, unit and principle in every question.
Second sit: redo three to seven days later, aiming for a faster finish.
What should I do after finishing this paper?
Direct answer: log questions with formula or sign errors; redo in three to seven days; and drill Section I multiple choice.
FAQ
Is this a College Board paper?
No. The questions and answers are TutorZone originals, not College Board questions or marking references.
What does AP Chemistry test?
Section I multiple choice, 60 questions, 1 h 30 min, 50%; Section II free response, 7 questions, 1 h 45 min, 50%.
How does ΔG indicate spontaneity?
ΔG < 0 spontaneous, ΔG > 0 non-spontaneous, ΔG = 0 at equilibrium.
Official references
| Resource | What to check |
|---|---|
| College Board AP Chemistry exam page | Confirm the format and question counts |
| https://www.tutorzone.com.hk/en-ap-physics-1-mock-2027/ | AP Physics 1 mock |
Related: practice area · AP Chemistry drilling guide (order and 12-week plan) · AP Physics 2 mock
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