(a) Chlorine dioxide undergoes the following reaction in aqueous solution. 2ClO₂ + 2OH⁻ → ClO₂⁻ + ClO₃⁻ + H₂O The initial rate of the reaction was measured at different initial concentrations of ClO₂ and OH⁻. The table shows the results obtained. [Table with columns: 'experiment', '[ClO₂] /mol dm⁻³', '[OH⁻] /mol dm⁻³', 'initial rate /mol dm⁻³ s⁻¹' and rows for experiments 1, 2, 3 with data values]

1. (a)(i)Use the data in the table to determine the rate equation, showing the order with respect to each reactant. Show your reasoning.[3]
2. (a)(ii)Calculate the value of the rate constant, k, using the data from experiment 2. State its units. k = units[2]
3. (b)(i)Explain the difference between heterogeneous and homogeneous catalysts.[2]
4. (b)(ii)Complete the table using ticks (√) to indicate whether the catalyst used in the reaction is heterogeneous or homogeneous. catalysed reaction heterogeneous homogeneous manufacture of ammonia in the Haber process removal of nitrogen oxides from car exhausts oxidation of sulfur dioxide in the atmosphere[2]
5. (c)(i)Balance the equation for this reaction. ....MnO₄⁻ + .......H⁺ + ....(CO₂H)₂ → ......Mn²⁺ + ....CO₂ + ....H₂O[2]
6. (c)(ii)The graph shown is a concentration-time graph for a typical reaction. [Figure: concentration of reactant vs time, typical exponential decay curve] On the axes below, sketch the curve you would expect for the autocatalysed reaction in (i). [Figure: empty axes for concentration of MnO₄⁻ vs time][2]
7. (d)(i)Describe, with the aid of a reaction pathway diagram, the effect of a catalyst on a reversible reaction. Suggest why catalysts are used in industrial processes.[3]
8. (d)(ii)The reaction for the Haber process to produce ammonia is shown. N₂(g) + 3H₂(g) ⇌ 2NH₃(g) ΔH° = −92 kJ mol⁻¹ At 500°C, when pressure is measured in atmospheres, the numerical value of Kp for this equilibrium is 1.45 x 10⁻⁵. • Write the expression for Kp for this equilibrium. • Calculate the partial pressure of NH₃ at equilibrium at 500 °C, when the partial pressure of N₂ is 20 atm and that of H₂ is 60 atm. pNH3 = atm[2]

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