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AP Chemistry Practice Quiz: Reaction Rates

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 10 questions to check your progress.

Question 1 of 10

The study of the rate at which an amount of reactants is converted to products per unit of time is best defined as which of the following?

All Questions (10)

The study of the rate at which an amount of reactants is converted to products per unit of time is best defined as which of the following?

A) Chemical thermodynamics

B) Chemical kinetics

C) Stoichiometry

D) Chemical equilibrium

Correct Answer: B

The provided content explicitly defines the kinetics of a chemical reaction as 'the rate at which an amount of reactants is converted to products per unit of time.'

According to the provided information, all of the following are factors that can influence the rate of a chemical reaction EXCEPT:

A) Temperature

B) The final yield of the products

C) Surface area of reactants

D) Reactant concentrations

Correct Answer: B

The content lists reactant concentrations, temperature, surface area, and catalysts as factors influencing the reaction rate. The final yield is a measure of reaction efficiency (thermodynamics), not its speed (kinetics).

For the chemical reaction 2H₂(g) + O₂(g) → 2H₂O(g), the rate of disappearance of O₂ is observed. How does the rate of appearance of H₂O relate to the rate of disappearance of O₂?

A) The rate of appearance of H₂O is half the rate of disappearance of O₂.

B) The rate of appearance of H₂O is equal to the rate of disappearance of O₂.

C) The rate of appearance of H₂O is twice the rate of disappearance of O₂.

D) The rate of appearance of H₂O is four times the rate of disappearance of O₂.

Correct Answer: C

Based on the principle that rates of change are determined by stoichiometry, the ratio of the coefficients for H₂O (2) and O₂ (1) is 2:1. Therefore, for every one mole of O₂ that reacts, two moles of H₂O are produced, meaning the rate of appearance of H₂O is twice the rate of disappearance of O₂.

A chemist observes that a particular reaction is proceeding too slowly. Which of the following changes would most likely increase the rate of the reaction?

A) Decreasing the temperature of the reaction vessel.

B) Removing the catalyst.

C) Increasing the concentration of the reactants.

D) Using a larger, single piece of a solid reactant instead of a powder.

Correct Answer: C

The provided content states that the rate of a reaction is influenced by reactant concentrations. Increasing the concentration of reactants generally leads to a faster reaction rate.

Two experiments are conducted where a solid piece of zinc is added to an acid solution. In Experiment 1, a 5g block of zinc is used. In Experiment 2, 5g of powdered zinc is used. Which experiment would have a higher initial reaction rate and why?

A) Experiment 1, because the solid block has a higher density.

B) Experiment 2, because the powdered zinc has a greater surface area.

C) Both experiments will have the same rate because the mass of zinc is identical.

D) The rates cannot be compared without knowing the temperature.

Correct Answer: B

The content identifies surface area as a key factor influencing reaction rates. Powdering a solid dramatically increases its surface area, allowing for more contact with the other reactant and thus a faster reaction rate.

The relationship between the rates of change of reactant and product concentrations in a chemical reaction is primarily determined by the:

A) Temperature of the system

B) Presence of a catalyst

C) Stoichiometry in the balanced chemical equation

D) Initial concentrations of the reactants

Correct Answer: C

The content directly states that 'The rates of change of reactant and product concentrations are determined by the stoichiometry in the balanced chemical equation.'

A substance that influences the rate of a chemical reaction without being consumed in the process is known as a:

A) Reactant

B) Product

C) Catalyst

D) Solvent

Correct Answer: C

The content lists catalysts as one of the factors that influence the rate of a reaction. The definition of a catalyst is a substance that changes the rate of a reaction.

Consider the synthesis of ammonia: N₂(g) + 3H₂(g) → 2NH₃(g). If the concentration of H₂(g) is decreasing at a rate of 0.030 M/s, what is the rate of appearance of NH₃(g)?

A) 0.010 M/s

B) 0.020 M/s

C) 0.045 M/s

D) 0.060 M/s

Correct Answer: B

Based on the stoichiometry of the balanced equation, the rate of appearance of NH₃ is related to the rate of disappearance of H₂ by the ratio of their coefficients (2/3). Rate of NH₃ = (2/3) * Rate of H₂ = (2/3) * 0.030 M/s = 0.020 M/s.

Which of the following sets of conditions would be expected to produce the fastest rate for a reaction?

A) Low reactant concentration and low temperature.

B) High reactant concentration and low temperature.

C) Low reactant concentration and high temperature.

D) High reactant concentration and high temperature.

Correct Answer: D

The content states that reaction rate is influenced by reactant concentrations and temperature. Generally, higher concentrations and higher temperatures both lead to an increase in the reaction rate. Therefore, combining both high concentration and high temperature would result in the fastest rate.

The 'rate of a chemical reaction' refers to a change in an amount per unit of time. In the context of experimental parameters, this rate is a measure of:

A) How much energy is released by the reaction.

B) How the concentrations of species change over time.

C) Whether the reaction will proceed spontaneously.

D) The final ratio of products to reactants at equilibrium.

Correct Answer: B

The definition of kinetics involves the conversion of reactants to products per unit of time. Experimentally, this is measured by monitoring how the concentrations of reactants decrease or how the concentrations of products increase over a specific time interval.