Chemistry 9701 · AS & A Level · Reaction kinetics

Reaction kinetics — practice question

In aqueous solution, chlorine dioxide, $\text{ClO}_2$, reacts with hydroxide ions as shown. $2\text{ClO}_2 + 2\text{OH}^- \rightarrow \text{ClO}_3^- + \text{ClO}_2^- + \text{H}_2\text{O}$. A set of experiments is then performed with different concentrations of $\text{ClO}_2$ and $\text{OH}^-$. The table presents the results obtained.
(a(i))[1]

Explain what is meant by order of reaction.

(a(ii))[2]

Using the table data, determine the order of reaction for each reactant, $\text{ClO}_2$ and $\text{OH}^-$. Justify your answer.

(a(iii))[1]

Using your answer to (a)(ii), write the rate equation for this reaction.

(a(iv))[2]

Use your rate equation together with the data from experiment 1 to calculate the rate constant, $k$, for this reaction. Include the units of $k$.

(b(i))[1]

Draw the structure of the organic product produced in this reaction.

(b(ii))[1]

Using the graph, determine the rate of reaction at $100\,\text{s}$. Show how you obtained your answer.

(c)[1]

Sketch a concentration-time graph for a zero-order reaction. Use your graph to suggest how successive half-lives for a zero-order reaction change as the concentration of a reactant decreases. Show this by placing a tick (✓) in the appropriate box in the table.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: The exponent to which concentration is raised in the rate equation

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