AP Chemistry practice test
Practice questions for all nine AP Chemistry units: atoms, bonding, intermolecular forces, reactions, kinetics, thermochemistry, equilibrium, acids and bases, and electrochemistry. Answer in your browser and read the reasoning behind each answer.
Question 1 of 27
An element has two isotopes: 20% have a mass of 10 amu and 80% have a mass of 11 amu. What is its average atomic mass?
Question 2 of 27
Which atom has the highest first ionization energy?
Question 3 of 27
What is the ground-state electron configuration of iron (Fe, Z = 26)?
Question 4 of 27
What is the molecular geometry of NH₃?
Question 5 of 27
Which molecule is nonpolar even though it contains polar bonds?
Question 6 of 27
Which substance is held together mainly by ionic bonds?
Question 7 of 27
Which substance has the highest boiling point?
Question 8 of 27
A gas occupies 4.0 L at 2.0 atm. At constant temperature, the pressure is raised to 4.0 atm. What is the new volume?
Question 9 of 27
What is the molarity of a solution made by dissolving 0.50 mol of NaCl in enough water to make 250 mL of solution?
Question 10 of 27
Solutions of AgNO₃ and NaCl are mixed and a white precipitate forms. What is the net ionic equation?
Question 11 of 27
For 2H₂ + O₂ → 2H₂O, how many moles of water form from 4.0 mol of H₂ with excess O₂?
Question 12 of 27
What is the oxidation number of manganese in KMnO₄?
Question 13 of 27
When the concentration of reactant A is doubled, the reaction rate doubles. What is the order of the reaction with respect to A?
Question 14 of 27
How does a catalyst increase the rate of a reaction?
Question 15 of 27
A first-order reaction has a half-life of 10 minutes. What fraction of the reactant remains after 30 minutes?
Question 16 of 27
For an exothermic reaction, which statement is true?
Question 17 of 27
How much heat is needed to raise 100 g of water by 10 °C? (c = 4.18 J/g·°C)
Question 18 of 27
Which statement about chemical bonds is correct?
Question 19 of 27
A system is at equilibrium. More reactant is added. According to Le Chatelier's principle, the system will
Question 20 of 27
For a reaction, the reaction quotient Q is smaller than the equilibrium constant K. What happens?
Question 21 of 27
For an exothermic reaction at equilibrium, what happens to K when temperature increases?
Question 22 of 27
What is the pH of a 0.010 M HCl solution?
Question 23 of 27
Which pair could be used to make a buffer?
Question 24 of 27
At 25 °C, a solution has [H⁺] = 1 × 10⁻³ M. What is its pOH?
Question 25 of 27
A reaction has ΔH < 0 and ΔS > 0. When is it thermodynamically favorable?
Question 26 of 27
In a galvanic (voltaic) cell, where does oxidation occur?
Question 27 of 27
A cell has a positive standard cell potential, E°cell > 0. What does this mean about ΔG°?
AP Chemistry key terms
Flip through these flashcards to review the terms that come up most often. Use the arrow keys or click a card to flip it.
| Effective nuclear charge | The net positive charge an outer electron feels; it increases across a period and explains most periodic trends. |
| VSEPR theory | Electron domains around a central atom spread out to minimize repulsion, which determines molecular shape. |
| Hydrogen bonding | Strong dipole attraction between H bonded to N, O or F and a lone pair on another N, O or F. |
| Ideal gas law | PV = nRT |
| Molarity | Moles of solute per liter of solution (mol/L). |
| Limiting reactant | The reactant that runs out first and determines how much product forms. |
| Rate law | Rate = k[A]ᵐ[B]ⁿ; the orders m and n are found from experiment, not from coefficients. |
| Activation energy | The minimum energy colliding particles need to react; catalysts lower it. |
| Specific heat equation | q = mcΔT |
| Le Chatelier's principle | A system at equilibrium shifts to partly offset a change in concentration, pressure or temperature. |
| Buffer | A solution of a weak acid and its conjugate base (or weak base and conjugate acid) that resists pH change. |
| Gibbs free energy | ΔG = ΔH − TΔS; a negative ΔG means the process is thermodynamically favorable. |
| Anode vs. cathode | Oxidation happens at the anode, reduction at the cathode. |
See all 13 cards
Effective nuclear chargeThe net positive charge an outer electron feels; it increases across a period and explains most periodic trends.
VSEPR theoryElectron domains around a central atom spread out to minimize repulsion, which determines molecular shape.
Hydrogen bondingStrong dipole attraction between H bonded to N, O or F and a lone pair on another N, O or F.
Ideal gas lawPV = nRT
MolarityMoles of solute per liter of solution (mol/L).
Limiting reactantThe reactant that runs out first and determines how much product forms.
Rate lawRate = k[A]ᵐ[B]ⁿ; the orders m and n are found from experiment, not from coefficients.
Activation energyThe minimum energy colliding particles need to react; catalysts lower it.
Specific heat equationq = mcΔT
Le Chatelier's principleA system at equilibrium shifts to partly offset a change in concentration, pressure or temperature.
BufferA solution of a weak acid and its conjugate base (or weak base and conjugate acid) that resists pH change.
Gibbs free energyΔG = ΔH − TΔS; a negative ΔG means the process is thermodynamically favorable.
Anode vs. cathodeOxidation happens at the anode, reduction at the cathode.
About the AP Chemistry exam
- Section I: 60 multiple-choice questions in 90 minutes, 50% of the score.
- Section II: 7 free-response questions in 105 minutes (3 long, 4 short), 50% of the score.
- Calculators are allowed on the whole exam, and a periodic table and equation sheet are provided.
Questions
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No. They are original practice questions written to match the topics and style of the AP Chemistry course. For released exam questions, see AP Central from the College Board.
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