Lesson 3.1.9.2

3.1.9.2 Determination of rate equation Quiz: AQA Chemistry, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson 3.1.9.2, Determination of rate equation: 20 multiple choice questions for the AQA Chemistry (7405), Unit 1: Physical chemistry, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. On a concentration-time graph, how is the rate of reaction at a particular time found?

    • By measuring the height of the curve above the time axis at its end point
    • By reading the concentration at that time and dividing it by the total time
    • By finding the area under the curve from the start up to that time
    • By drawing a tangent to the curve at that time and finding its gradient

  2. Why is the initial rate method based on the concentrations at the start of the reaction?

    • The equilibrium position is established at the start, so the rate is fixed at that time
    • The catalyst is only active at the start of the reaction, so rates are measured then
    • Concentrations have changed very little at the start, so the rate is approximately constant then
    • Concentrations are at their maximum at the start, so the rate is at its highest value then

  3. In a rate experiment, doubling [A] doubles the initial rate. What is the order with respect to A?

    • 0
    • 1
    • 3
    • 2

  4. In a rate experiment, doubling [A] quadruples the initial rate. What is the order with respect to A?

    • 2
    • 4
    • 1
    • 0

  5. In a rate experiment, doubling [A] has no effect on the initial rate. What is the order with respect to A?

    • 0
    • 1
    • 2
    • -1

  6. Experiment 1 and Experiment 2 differ only in [B]: [B] doubles and the rate increases four times. What is the order with respect to B?

    • 4
    • 2
    • 1
    • 0

  7. Rate data show that tripling [B] at constant [A] increases the rate by a factor of 9. What is the order with respect to B?

    • 2
    • 1
    • 9
    • 3

  8. Rate data show that doubling [A] doubles the rate and doubling [B] has no effect. What is the rate equation?

    • Rate = k[B]
    • Rate = k[A]^2
    • Rate = k[A][B]
    • Rate = k[A]

  9. A reaction has rate equation Rate = k[NO]^2[H2]. Which molecules are involved in the rate-determining step?

    • Two molecules of NO and one molecule of H2
    • Two molecules of NO and two molecules of H2
    • One molecule of NO and two molecules of H2
    • One molecule of NO and one molecule of H2

  10. Which concentration-time graph shape indicates a zero-order reaction?

    • A curve whose gradient becomes steadily more negative
    • A straight line with a constant negative gradient
    • A horizontal line with zero gradient at all times
    • A curve that approaches zero concentration with a decreasing gradient

  11. A concentration-time graph for a zero-order reaction has a gradient of -0.020 mol dm^-3 s^-1. What is the rate constant k?

    • 0.020 mol dm^-3 s^-1
    • 0.0004 mol dm^-3 s^-1
    • 0.020 s^-1
    • 50 mol dm^-3 s^-1

  12. In the iodine clock reaction, why is the time for a fixed amount of product to form used to find the initial rate?

    • The rate is inversely proportional to the time taken, so a shorter time means a faster initial rate
    • The time gives the activation energy directly, so the rate is not needed
    • The time is equal to the rate constant, so the reaction is zero order
    • The rate is directly proportional to the time taken, so a longer time means a faster initial rate

  13. What does the continuous monitoring method for measuring rate involve?

    • Measuring the temperature of the solution only once at the end of the reaction
    • Recording a property such as gas volume or mass loss against time throughout the reaction
    • Measuring the rate only at the start of the reaction with fresh reactants each time
    • Adding a single sample to a reagent at the end of the reaction and titrating it

  14. What does the initial rate method involve?

    • Measuring the rate once, at the end of a long reaction, with a single set of concentrations
    • Repeating the experiment with different starting concentrations and measuring the early rate each time
    • Recording a continuous graph and using only its final gradient to find the rate
    • Measuring the rate of a reaction only when the catalyst is removed from the mixture

  15. A tangent drawn to a concentration-time curve has a gradient of -0.0050 mol dm^-3 s^-1 at a given time. What is the rate of reaction at that time?

    • 0.0050 s^-1
    • -0.0050 mol dm^-3 s^-1
    • 0.0050 mol dm^-3 s^-1
    • 200 mol dm^-3 s^-1

  16. In a reaction where doubling [B] has no effect on the rate, what happens to the rate if [B] is halved at constant [A]?

    • It is unchanged, because the reaction is zero order with respect to B
    • It doubles, because the reaction is first order with respect to B only
    • It halves, because the reaction is first order with respect to B
    • It falls to a quarter, because the reaction is second order with respect to B

  17. Concentration-time data for a reaction are: [A] = 0.50 at t = 0 s, 0.40 at 10 s and 0.30 at 20 s mol dm^-3. What are the rate and the order with respect to A?

    • 0.020 mol dm^-3 s^-1, zero order
    • 0.010 mol dm^-3 s^-1, first order
    • 0.050 mol dm^-3 s^-1, second order
    • 0.010 mol dm^-3 s^-1, zero order

  18. A rate experiment shows that doubling [A] and tripling [B] at constant temperature increases the rate by a factor of 18. What is the rate equation?

    • Rate = k[A][B]
    • Rate = k[A]^2[B]
    • Rate = k[A][B]^2
    • Rate = k[A]^2[B]^2

  19. Which practical method is used to determine the order of reaction when concentrations are changed one at a time?

    • The measurement of the enthalpy change for a single reaction at constant pressure
    • The continuous monitoring method, in which only one experiment is run at constant concentration
    • The initial rate method, in which each experiment is run with a different starting concentration
    • The measurement of pH at equilibrium in a closed vessel only

  20. A reaction has order 2 with respect to A and order 0 with respect to B. Which change increases the rate?

    • Doubling [B] at constant [A], which increases the rate by a factor of two
    • Doubling [B] at constant [A], which increases the rate by a factor of four
    • Doubling [A] at constant [B], which increases the rate by a factor of four
    • Doubling [A] at constant [B], which increases the rate by a factor of two

All AQA Chemistry quizzes