CSEC Chemistry · May/June 2010 · Paper 2 · Question 1(a)(v)b)

Jonathan and Karen conducted experiments on the decomposition of hydrogen peroxide using manganese(IV) oxide as a catalyst. Jonathan used 100 cm³ of 0.80 mol dm⁻³ hydrogen peroxide, measuring oxygen volume over time (Table 1). Karen used 100 cm³ of 0.40 mol dm⁻³ hydrogen peroxide, with her results shown in Figure 1. The decomposition is exothermic, producing water and oxygen. Figure 2 illustrates the enthalpy change for an exothermic reaction and the effect of a catalyst.

Determine the number of moles of oxygen produced in 45 seconds at RTP (room temperature and pressure). (1 mole of gas occupies 24 dm³ at RTP: Relative Atomic Mass O = 16)

This question uses a figure or table from the paper — you'll see it when you practise.