Simple rate equations, orders of reaction and rate constants: past paper questions

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• Question 3May/June 2026, paper 41Structured9 marks

  Nitrogen monoxide reacts with hydrogen to produce nitrogen and water. $$2\text{NO}+2{\text{H}}_2\to {\text{N}}_2+2{\text{H}}_2\text{O}$$ The rate equation for this reaction is shown.

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• Question 3Oct/Nov 2025, paper 41Structured11 marksHas a diagram

  Solid manganese(IV) oxide, ${\text{MnO}}_2$, catalyses the decomposition of hydrogen peroxide. $$2{\text{H}}_2{\text{O}}_2(\text{aq})\to 2{\text{H}}_2\text{O}(\text{l})+{\text{O}}_2(\text{g})$$ State the type of catalysis for this reaction.

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• Question 1Oct/Nov 2023, paper 42Structured10 marks

  Propanone, $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{C}{\mathrm{H}}_3$, reacts with iodine, ${\mathrm{I}}_2$, in the presence of an acid catalyst. $$\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{C}{\mathrm{H}}_3+{\mathrm{I}}_2\to \mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{C}{\mathrm{H}}_2\mathrm{I}+{\mathrm{H}}^{+}+{\mathrm{I}}^{-}$$ The rate equation for this reaction is shown.

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• Question 3May/June 2026, paper 42Structured10 marks

  Ethanal, ${\text{CH}}_3\text{CHO}$, reacts with methanol, ${\text{CH}}_3\text{OH}$, under acidic conditions to form compound B, as shown in reaction 1.

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• Question 2Oct/Nov 2025, paper 42Structured9 marks

  Ethanal, $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{H}\mathrm{O}$, reacts with nitrogen dioxide, $\mathrm{N}{\mathrm{O}}_2$. The products of the first step of this reaction are a $\mathrm{C}{\mathrm{H}}_3\dot{\mathrm{C}}=\mathrm{O}$ radical and a molecule of nitrous acid, $\mathrm{H}\mathrm{N}{\mathrm{O}}_2$.

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• Question 1Oct/Nov 2024, paper 42Structured14 marksHas a diagram

  The equation for reaction 1 is shown. $$\text{reaction 1}\text{X}\to 2\text{Y}$$ Reaction 1 is first order with respect to the concentration of X. The half-life of the reaction, $t_{\frac{1}{2}}$, is $900\text{ s}$ at $20{}^{\circ }\text{C}$.

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• Question 3May/June 2023, paper 41Structured10 marksHas a diagram

  Aqueous acidified iodate(V) ions, $\mathrm{I}{\mathrm{O}}_3^{-}$, react with iodide ions, as shown. $\mathrm{I}{\mathrm{O}}_3^{-}+6{\mathrm{H}}^{+}+5{\mathrm{I}}^{-}\to 3{\mathrm{I}}_2+3{\mathrm{H}}_2\mathrm{O}$ The initial rate of this reaction is investigated. Table 3.1 shows the results obtained.

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• Question 3Oct/Nov 2024, paper 43Structured16 marks

  $\mathbf{A}$ and $\mathbf{B}$ react together to give product $\mathrm{A}\mathrm{B}$.

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• Question 4May/June 2023, paper 42Structured10 marksHas a diagram

  In aqueous solution, iron(III) ions react with iodide ions, as shown. $$2{\text{Fe}}^{3+}+2{\text{I}}^{-}\to 2{\text{Fe}}^{2+}+{\text{I}}_2$$ A series of experiments is carried out using different concentrations of ${\text{Fe}}^{3+}$ and ${\text{I}}^{-}$, as shown in Table 4.1.

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• Question 2May/June 2025, paper 41Structured10 marks

  Three experiments are carried out to investigate the reaction of nitrogen oxide, $\mathrm{N}\mathrm{O}$, with chlorine. $$2\mathrm{N}\mathrm{O}+{\mathrm{C}\mathrm{l}}_2\to 2\mathrm{N}\mathrm{O}\mathrm{C}\mathrm{l}$$ The rate equation for this reaction is shown.

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• Question 4May/June 2025, paper 42Structured10 marksHas a diagram

  In aqueous solution, iodide ions react with acidified hydrogen peroxide, as shown in reaction 1. $$\text{reaction 1}2{\mathrm{I}}^{-}+{\mathrm{H}}_2{\mathrm{O}}_2+2{\mathrm{H}}^{+}\to {\mathrm{I}}_2+2{\mathrm{H}}_2\mathrm{O}$$ The rate equation for reaction 1 is shown.

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• Question 5May/June 2024, paper 42Structured9 marks

  Nitrosyl chloride, $\text{NOCl}$, can be formed by the reaction between nitrogen monoxide and chlorine, as shown.

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