For a reaction at fixed conditions, $Q<K$. In which direction does the system initially shift?
Correct answer: Toward products
Why: When $Q<K$, there are too few products relative to equilibrium, so the reaction proceeds toward products.
AP Chemistry Practice Questions
Answer original AP-style diagnostic questions, review explanations, and identify the next unit to study.
AP Chemistry diagnostic practice set
These are original practice questions, not copied College Board items. Use official released questions for final calibration.
Question 1 of 3
Review the reasoning after you finish
The interactive set keeps answers hidden while you work. This review section remains crawlable and gives every student a complete correction path after the attempt.
Which quantity is changed by adding a catalyst?
Correct answer: The activation-energy pathway
Why: A catalyst provides an alternative pathway with lower activation energy; it does not change the equilibrium position or overall thermodynamics.
At the half-equivalence point of a weak-acid titration, which relationship is true?
Correct answer: $\mathrm{pH}=\mathrm{p}K_a$
Why: At half-equivalence, $[\mathrm{HA}]=[\mathrm{A^-}]$. The Henderson–Hasselbalch equation therefore gives $\mathrm{pH}=\mathrm{p}K_a$.
Practise each section under its own calculator rule
Practising with a calculator you will not be handed is the most common way a practice score stops predicting an exam score. Set each practice block up to match the section it rehearses.
| Section or part | What you may use | What that means for your work |
|---|---|---|
| Multiple choice | No calculator | This is the rule that surprises students most. Every multiple-choice number must be estimated or cancelled by hand. |
| Free response | Scientific or graphing calculator | Full arithmetic allowed - and expected, with the setup shown. |
| Provided for the whole exam | Periodic table and equations and constants sheet | Both sections get them. Practise finding a value on the sheet quickly instead of memorising constants. |
How practice should cover the complete course
Atomic Structure and Properties
Moles, spectra, electron configuration, periodic trends
7–9%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Compound Structure and Properties
Bonding, Lewis structures, forces
7–9%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Properties of Substances and Mixtures
Intermolecular forces, solutions, spectroscopy
18–22%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Chemical Reactions
Equations, stoichiometry, titration
7–9%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Kinetics
Rate laws, mechanisms, activation energy
7–9%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Thermochemistry
Energy, calorimetry, enthalpy
7–9%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Equilibrium
K, Q, Le Châtelier, solubility
7–9%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Acids and Bases
pH, buffers, titration, structure
11–15%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Thermodynamics and Electrochemistry
Entropy, Gibbs energy, cells
7–9%: practice one recognition question, one direct application, and one mixed prompt that requires you to choose this unit without being told.
Use the result to focus your AP Chemistry review
Read the score as a map, not a verdict
Each answer shows a relationship between course knowledge and an exam decision. A miss may mean that a definition is unclear, a representation was misread, or the right method was not selected. Compare each miss with these AP Chemistry priorities before choosing the next unit or practice set.
- Particle diagrams with conservation
- Unit-aware calculations
- Equilibrium versus kinetics
- Acid-base species and approximations
- Claim-evidence-reasoning on FRQs
Next steps after the AP Chemistry diagnostic
Use a four-step correction cycle
- Write the rule or idea behind every miss.
- Solve a second problem of the same type without looking back.
- Mix that skill with two older units tomorrow.
- Complete official released questions under authentic timing.
Questions about AP Chemistry exam practice
How many questions are on the AP Chemistry exam?
The published format is 60 questions on multiple choice and 7 questions on free response. Multiple choice — About 1.5 minutes each with no calculator. Practise cancelling units and rounding to one significant figure to check which answer is possible. Free response — About 15 minutes each. The long questions carry far more points than the short ones - do not spend equal time on all seven.
Which AP Chemistry units should I practise first?
Start with the heaviest published weightings: Properties of Substances and Mixtures (18–22%), Acids and Bases (11–15%), Atomic Structure and Properties (7–9%). Then repair whichever earlier unit those depend on.
Can I use a graphing calculator while I practise for AP Chemistry?
Only where the exam allows one, and practising otherwise builds the wrong habit. Multiple choice: This is the rule that surprises students most. Every multiple-choice number must be estimated or cancelled by hand. Free response: Full arithmetic allowed - and expected, with the setup shown. Provided for the whole exam: Both sections get them. Practise finding a value on the sheet quickly instead of memorising constants.
What is the most common way students lose points on AP Chemistry?
Answering 'why' by restating the observation. 'It has a higher boiling point because it boils at a higher temperature' scores nothing. Name the intermolecular force and compare strengths.
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