Chemistry 9701 · AS & A Level · Reaction kinetics

Reaction kinetics — practice question

The equation $\text{2NO(g)} + \text{O}_2\text{(g)} \rightarrow \text{2NO}_2\text{(g)}$ represents the oxidation of nitrogen(II) oxide. Initial rates were measured while the starting concentrations of the two reactants were varied. The results are given below.
(a(i))

From the table, determine the order for each reactant. Show your working.

(a(ii))

Calculate the initial rate in experiment $4$. Give your answer to two significant figures.

(a(iii))

Write the rate equation for the reaction.

(a(iv))[6]

Use the results from experiment $1$ to calculate the rate constant, $k$, for this reaction. Include the units of $k$.

(b(i))

On the axes below, draw two Boltzmann distribution curves at two different temperatures, $T_1$ and $T_2$ ($T_2 > T_1$), and label the curves as well as the axes.

(b(ii))[5]

State and explain, using your diagram, the effect on the rate of reaction when temperature is increased.

(c)[2]

The compound nitrosyl fluoride, NOF, can be made by the reaction $\text{2NO(g)} + \text{F}_2\text{(g)} \rightleftharpoons \text{2NOF(g)}$. The rate is first order with respect to NO and $\text{F}_2$. The reaction mechanism consists of two steps. Suggest equations for the two steps of this mechanism, stating which is the slower rate-determining step.

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