An oxygen generator contains potassium chlorate, KClO3\mathrm{KClO_3}KClO3. When heated, the potassium chlorate decomposes.
2KClO3(s)→2KCl(s)+3O2(g) \mathrm{2KClO_3(s) \rightarrow 2KCl(s) + 3O_2(g)} 2KClO3(s)→2KCl(s)+3O2(g)The oxygen produced is collected in a gas syringe. The gas syringe is allowed to return to room temperature and pressure before the final reading is taken.
| Reading | Gas syringe volume (cm3\mathrm{cm^3}cm3) |
|---|---|
| Before heating | 8.0 |
| After heating | 80.0 |
One mole of any gas occupies 24 dm3 at room temperature and pressure.
Relative atomic masses (ArA_rAr): K = 39.1, Cl = 35.5, O = 16.0
Calculate the mass of potassium chlorate that decomposed.
Give your answer to three significant figures.
152 exam-style questions on OCR GCSE Chemistry 5.1 Monitoring chemical reactions, covering 5.1.1 The technique of titration, 5.1.2 Theoretical mass, percentage yield and atom economy, 5.1.3 Concentration of a solution in mol/dm3, 5.1.4 Concentration calculations and titration results, 5.1.5 Molar gas volume and volumes of gases in reactions, and 5.1.6 Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.