Rate Equations (A Level only) (AQA A Level Chemistry)

Exam Questions

3 hours30 questions
11 mark

The reaction between iodine and propanone can be catalysed by sulfuric acid. The rate equation shows that this reaction is first order with respect to propanone:

Rate = k [H+] [C3H6O]

Which graph shows that the reaction is first order with respect to propanone?

5-2-rate-equations--mcq--q-no-1

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    21 mark

    Substances A and B react in solution according to the equation.

                                                               A + 2B → C + 2D

    The results of an investigation of the reaction between A and B are shown in this table.

    Experiment 

    Initial [A] 

    / mol dm–3

    Initial [B] 

    / mol dm–3

    Initial rate

    / mol dm–3 s–1

    1

    0.25

    0.25

    3.5 ×10-4

    2

    0.25

    0.50

    To be calculated

    The rate equation for this reaction is rate = k [B]

    What is the initial rate of reaction for experiment 2?

    • 1.4 × 10-3 mol dm–3 s–1

    • 7.0 × 10-4 mol dm–3 s–1

    • 3.5 ×10-4 mol dm–3 s–1

    • 1.75 ×10-4 mol dm–3 s–1

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    31 mark

    The rate equation for the reaction between A and B is:

                                                             Rate = k [A] [B]

    What are the correct units for the rate constant of this rate equation?

    • mol dm-3 s-1

    • mol2 dm−6 s−1

    • mol−2 dm6 s−1

    • mol-1 dm3 s-1

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    41 mark

    The Arrhenius equation is shown below.

    k space equals space A e to the power of bevelled fraction numerator negative E subscript a over denominator R T end fraction end exponent

    Which term from the Arrhenius equation has the incorrect units?

           

       Term      

        Units 

    A

    Ea 

    J mol-1 

    B

    J K-1 mol-1 

    C

    K-1

    D

    No units

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      51 mark

      An alternative version of the Arrhenius equation is:

                                                 ln k =fraction numerator negative E subscript a over denominator R end fraction 1 over T + In A

      Which specific term can be calculated from an Arrhenius plot, shown below, using this equation?

      5-2-e-q5-aqa-al-chemistry

      • Ea

      • 1 over T

      • R

      • 1 over R

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      11 mark

      The reaction between iodine and propanone can be catalysed by sulfuric acid. The rate equation for this reaction is:

      Rate = k [H+] [C3H6O]

      Which of the following sets of statements is correct about the order of reaction with respect to each chemical involved? 

       

                 Iodine 

          Propanone

          Sulfuric acid

       A 

      Zero

      First

      Second

      B

      First

      Zero

      First

      C

      Zero

      First

      First

      D

      Zero 

      Second

      Zero

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        21 mark

        For the general reaction V + W + X → Y + Z, the rate equation is: 

                                                             rate = k [V] [W] [X]

        What will happen to the rate of reaction when the concentration of all three reactants is doubled?

        • Increase by a factor of 2

        • Increase by a factor of 4

        • Increase by a factor of 6

        • Increase by a factor of 8

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        31 mark

        The general reaction D + E F + G uses an acid catalyst, H.

        The rate equation for this fourth order reaction is rate = k [D] [E]2.

        Which of the following sets of statements is correct about the order of reaction with respect to each chemical involved.

         

         

        D

        E

        H

        A

        First

        First

        Zero

        B

        First

        First

        Second

        C

        First

        Second

        Zero

        D

        First

        Second

        First

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          41 mark

          Two compounds, X and Y, were reacted together.

          The initial rate of reaction when compound X and compound Y were reacted together was measured in a series of experiments.

          The temperature was kept constant and the results of the experiments are shown below.

          Expt.

          Initial [X] / mol dm-3

          Initial [Y] / mol dm-3

          Initial rate / mol dm-3 s-1

          1

          0.030

          0.020

          4.0 x 10-4

          2

          0.030

          0.030

          6.0 x 10-4

          3

          0.060

          0.030

          1.2 x 10-3

          What are the correct orders with respect to X and Y?

           

          X

          Y

          A

          Second

          Second

          B

          First

          First

          C

          Second

          First

          D

          First

          Second

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            51 mark

            An investigation into the rate of reaction between compounds A and B was performed.

            A + B → Products

            The results from three different experiments carried out at a constant temperature are shown:

             

            Expt.

            Initial concentration of A / mol dm-3

            Initial concentration of B / mol dm-3

            Initial rate / mol dm-3 s-1

            1

            0.30

            0.50

            6.0 x 10-4

            2

            0.30

            0.25

            1.5 x 10-4

            3

            0.60

            0.25

            3.0 x 10-4

             

            The rate equation for this reaction is rate = k [A] [B]2

            What is the value of the rate constant, k?

            • 2.0 x 10-3

            • 3.2 x 10-2

            • 8.0 x 10-3

            • 2.7 x 10-2

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            11 mark

            The reaction between iodine and propanone can be catalysed by sulfuric acid. The rate equation for this reaction is:

            Rate = k [H+] [C3H6O]

             In reaction 1, the rate of reaction for a mixture of iodine, propanone and sulfuric acid at pH 0.72 was measured.

             Reaction 2 contained the same concentrations of iodine and propanone, but the concentration of sulfuric acid was changed. The rate of reaction for this mixture was found to be a quarter of the rate of reaction 1.

            What was the pH of the second mixture?

            • 0.44

            • 0.74

            • 1.02

            • 1.32

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            21 mark

            Two reactions between A and B were investigated. The results are shown in the table.

            Experiment

            Initial [A]

            / mol dm–3

            Initial [B]

            / mol dm–3

            Initial rate

            / mol dm–3 s–1

            1

            0.25

            0.50

            0.60

            2

            0.60

            To be calculated

            1.20

             

            The rate equation is rate = k [A]2 [B]2

            What is the initial concentration of B in experiment 2?

            • 0.09 mol dm–3

            • 0.29 mol dm–3

            • 0.65 mol dm–3

            • 0.83 mol dm–3

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            31 mark

            For the general reaction C + D + E F + G, the rate equation is rate = k [C]2 [D] [E]2.

            What factor will the rate of reaction increase by when the concentration of all reactants is doubled?

            • 8

            • 16

            • 32

            • 64

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            41 mark

            The results of three experiments carried out at a temperature, T1, to investigate the rate of the reaction between compounds H and J are shown in the table.

             

            Experiment 1

            Experiment 2

            Experiment 3

            Initial [H] / mol dm-3

            0.15

            0.21

            0.42

            Initial [J] / mol dm-3

            0.60

            0.60

            1.80

            Initial rate / mol dm-3 s-1

            2.84 x 10-5

            3.98 x 10-5

            7.16 x 10-4

             

            Using the data in the table, what is the correct rate equation for the reaction between compounds H and J?

            • Rate = k [H] [J]

            • Rate = k [H] [J]2

            • Rate = k [H]2 [J]

            • Rate = k [H]2 [J]2

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            51 mark

            In the reaction between compounds L and M at temperature, T1, the initial rate of reaction was found to be 2.96 x 10-2 mol dm-3 s-1.

            The rate constant, k, for the reaction is 782 mol-2 dm6 s-1 and the rate equation is:

            Rate    = k [L]2 [M]

            The initial concentrations of L and M were both y mol dm-3.

            What is the correct concentration of L and M?

            • 3.36 x 10-2 mol dm-3 

            • 6.15 x 10-3 mol dm-3

            • 2.98 x 101 mol dm-3  

            • 1.26 x 10-5 mol dm-3 

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