Chemistry 9701 · AS & A Level · Reaction kinetics

Reaction kinetics — practice question

Chlorate(I) ions react in aqueous solution according to the equation below. $2\text{NH}_3 + \text{ClO}^- \rightarrow \text{N}_2\text{H}_4 + \text{Cl}^- + \text{H}_2\text{O}$ A set of experiments was then performed using different concentrations of $\text{ClO}^-$ and $\text{NH}_3$. The table gives the outcomes.
(a(i))[2]

Use the table data to work out the order for each reactant, $\text{ClO}^-$ and $\text{NH}_3$. Show how you reached your answer.

(a(ii))[1]

Write down the rate equation for this reaction.

(a(iii))[2]

Use the data from experiment 1 to calculate the rate constant, $k$, for this reaction. State the units of $k$ as well.

(a(iv))[1]

On the axes sketch a graph to show how the value of $k$ varies as temperature is increased.

(b(i))[2]

Describe how the results from this experiment can be used to confirm that the reaction is first-order in $[\text{I}^-]$.

(b(ii))[1]

Use this mechanism to work out the overall equation for this reaction.

(b(iii))[1]

Identify a step that involves a redox reaction. Explain your answer.

(iv)[1]

On the axes sketch a graph showing how $k$ changes as temperature rises.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: order with respect to $[NH_3]$ is 2

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI