PYQ Vault
EbooksTutor

Rate, rate constant or concentration from a rate law with two reactants

This type of question, asked 16 times: 10 May 2023 S2, 11 May 2023 S2, 15 May 2023 S2, 16 May 2023 S1, 9 May 2024 S1, 9 May 2024 S2, 12 May 2024 S2, 13 May 2024 S2, 14 May 2024 S1, 25 Apr 2025 S1, 26 Apr 2025 S1, 13 Apr 2026 S1, 15 Apr 2026 S1, 15 Apr 2026 S2, 16 Apr 2026 S2, 13 May 2026 S1. All 16 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    10 May 2023 S2

    73
    For the reaction A+B→A + B \rightarrow product, rate law equation is rate =k[A]2[B]= k[A]^2[B]. If rate of reaction is 0.22 mol L−1 s−10.22\,\text{mol}\,\text{L}^{-1}\,\text{s}^{-1}, calculate rate constant. [A]=1 mol L−1[A] = 1\,\text{mol}\,\text{L}^{-1}, [B]=0.25 mol L−1[B] = 0.25\,\text{mol}\,\text{L}^{-1}

    Tap an option to check your answer.

  2. Question 2

    11 May 2023 S2

    78
    Rate law for a reaction is r=k[A]2[B]r = k[A]^2[B]. If rate constant is 6.25 mol−2dm6s−16.25\ \text{mol}^{-2}\text{dm}^6\text{s}^{-1}, what is the rate of reaction when [A]=1 mol dm−3[A] = 1\ \text{mol dm}^{-3} and [B]=0.2 mol dm−3[B] = 0.2\ \text{mol dm}^{-3}?

    Tap an option to check your answer.

  3. Question 3

    15 May 2023 S2

    75
    For reaction A+B→A + B \to product, rate of reaction is 3.6×10−2 sec−13.6 \times 10^{-2}\text{ sec}^{-1}. When [A]=0.2 mol dm−3[A] = 0.2\text{ mol dm}^{-3} and [B]=0.1 mol dm−3[B] = 0.1\text{ mol dm}^{-3}, calculate rate constant of reaction if reaction is first order in A and second order in B?

    Tap an option to check your answer.

  4. Question 4

    16 May 2023 S1

    75
    Rate of reaction, A+B→A + B \to product, is 7.2×10−2 mol dm−3s−17.2 \times 10^{-2}\,\text{mol dm}^{-3}\text{s}^{-1} at [A]=0.4 mol dm−3[A] = 0.4\,\text{mol dm}^{-3} and [B]=0.1 mol dm−3[B] = 0.1\,\text{mol dm}^{-3}. The reaction is first order in A and second order in B. Calculate rate constant.

    Tap an option to check your answer.

  5. Question 5

    9 May 2024 S1

    80
    The rate of reaction, A+B→A+B\to product, is 1.8×10−2 mol dm−3 s−11.8\times10^{-2}\,mol\,dm^{-3}\,s^{-1}. Calculate the rate constant if the reaction is second order in A and first order in B ([A]=0.2 M;[B]=0.1 M[A]=0.2\,M; [B]=0.1\,M)

    Tap an option to check your answer.

  6. Question 6

    9 May 2024 S2

    62
    The rate law for the reaction A+B→productA + B \to \text{product} is given by rate =k[A][B]= k[A][B]. Calculate [A] if rate of reaction and rate constant are 0.25 mol dm−3^{-3} s−1^{-1} and 6.25 mol−1^{-1} dm³ s−1^{-1} respectively, [B]=0.25[B] = 0.25 mol dm−3^{-3}.

    Tap an option to check your answer.

  7. Question 7

    12 May 2024 S2

    84
    The rate law for the reaction A+B→CA + B \rightarrow C at 25°C25°C is given by rate =k[A][B]2= k[A][B]^2. Calculate the rate of reaction if rate constant at same temperature is 6.256.25 mol⁻² dm⁶ s⁻¹, [A]=1[A] = 1 M, [B]=0.2[B] = 0.2 M

    Tap an option to check your answer.

  8. Question 8

    13 May 2024 S2

    95
    For the reaction 2A+2B→2C+D2\text{A}+2\text{B}\to2\text{C}+\text{D}, the rate law is expressed as rate =k[A]2[B]=k[\text{A}]^2[\text{B}]. Calculate the rate constant if rate of reaction 0.24 mol dm−3 s−10.24\ \text{mol dm}^{-3}\ \text{s}^{-1} [A]=0.5 M[\text{A}]=0.5\ \text{M} and [B]=0.2 M][\text{B}]=0.2\ \text{M}]

    Tap an option to check your answer.

  9. Question 9

    14 May 2024 S1

    71
    The rate for reaction 2A+B→2\text{A}+\text{B}\rightarrow product is 6×10−4 mol dm−3s−16\times10^{-4}\,\text{mol dm}^{-3}\text{s}^{-1}. Calculate the rate constant if the reaction is first order in A and zeroth order in B. [Given [A]=[B]=0.3 M[\text{A}]=[\text{B}]=0.3\,\text{M}]

    Tap an option to check your answer.

  10. Question 10

    25 Apr 2025 S1

    82
    If r=k[A]2[ B]r = k\lbrack A\rbrack^{2}\lbrack\text{ }B\rbrack is rate law equation for reaction A+B→CA + B \rightarrow C, at [A]=1M\lbrack A\rbrack = 1M and, [B]=0.2M\lbrack B\rbrack = 0.2M, Calculate rate of reaction if rate constant is 6.25M−2 s−16.25M^{- 2}{\text{ }s}^{- 1}.

    Tap an option to check your answer.

  11. Question 11

    26 Apr 2025 S1

    70
    Rate of the reaction A+B⟶A + B \longrightarrow product is 3.6×10−2 moldm−3 s−13.6 \times10^{- 2}\text{ }moldm^{- 3}{\text{ }s}^{- 1} and rate law is r=k[A][B]2r = k\lbrack A\rbrack\lbrack B\rbrack^{2}. What is rate constant of the reaction if [A]=0.2M\lbrack A\rbrack = 0.2M and [B]=0.1M\lbrack B\rbrack = 0.1M ?

    Tap an option to check your answer.

  12. Question 12

    13 Apr 2026 S1

    26
    For the reaction, A+B→PA + B \rightarrow P, the rate law is rate =k[A][B]2= k[A][B]^2. The rate of reaction is 0.25 Ms−10.25\ \mathrm{Ms^{-1}} when [A]=1[A] = 1 M, [B]=0.2[B] = 0.2 M at 25∘25^\circC. Calculate the rate constant of the reaction at the same temperature.

    Tap an option to check your answer.

  13. Question 13

    15 Apr 2026 S1

    28
    The rate of the reaction 2A+3B→2C+D2A + 3B \rightarrow 2C + D is 6×10−4 mol dm−3 s−16 \times 10^{-4}\ \mathrm{mol\ dm^{-3}\ s^{-1}}, when [A]=[B]=0.3 mol dm−3[A] = [B] = 0.3\ \mathrm{mol\ dm^{-3}}. If the reaction is of first order for A and zeroth order for B, then find the rate constant.

    Tap an option to check your answer.

  14. Question 14

    15 Apr 2026 S2

    27
    The rate of reaction A+B→P\mathrm{A + B \rightarrow P} is 4×10−2 mol dm−3 s−14 \times 10^{-2}\ \mathrm{mol\,dm^{-3}\,s^{-1}} When [A]=0.2 mole dm−3[A] = 0.2\ \mathrm{mole\,dm^{-3}} and [B]=0.1 mole dm−3[B] = 0.1\ \mathrm{mole\,dm^{-3}}, What is the rate constant of reaction, if it is first order with respect to A and second order with respect to B ?

    Tap an option to check your answer.

  15. Question 15

    16 Apr 2026 S2

    28
    The rate law for the reaction A+B→PA + B \rightarrow P is found to be rate =k[A]2[B]= k[A]^2[B]. The rate constant of the reaction at 300 K is 6.0 M−2s−16.0\ \mathrm{M^{-2}s^{-1}}. Calculate the rate of the reaction when [A]=1[A] = 1 M and [B]=0.2[B] = 0.2 M

    Tap an option to check your answer.

  16. Question 16

    13 May 2026 S1

    26
    The rate of reaction, A+B→CA + B \rightarrow C is 3.6×10−2 mol dm−3 s−13.6 \times 10^{-2}\ \mathrm{mol\,dm^{-3}\,s^{-1}} when [A]=[B]=0.2 mol dm−3[A] = [B] = 0.2\ \mathrm{mol\,dm^{-3}}. Calculate the rate constant if the reaction is first order in A and second order in B.

    Tap an option to check your answer.