A student investigates the thermal decomposition of sodium chlorate(V) to produce sodium chloride and oxygen gas:
2NaClO3(s)→MnO2(s)2NaCl(s)+3O2(g) 2\text{NaClO}_3(\text{s}) \xrightarrow{\text{MnO}_2(\text{s})} 2\text{NaCl}(\text{s}) + 3\text{O}_2(\text{g}) 2NaClO3(s)MnO2(s)2NaCl(s)+3O2(g)The student heats a mixture containing 12.55 g of sodium chlorate(V) and 3.50 g of manganese(IV) oxide as a catalyst. During the reaction, 3.84 g of oxygen gas is evolved and escapes from the reaction vessel.
What is the mass of the manganese(IV) oxide catalyst remaining in the vessel at the end of the reaction?
3.50 g3.50\text{ g}3.50 g
12.21 g12.21\text{ g}12.21 g
8.71 g8.71\text{ g}8.71 g
0.00 g0.00\text{ g}0.00 g
31 exam-style questions on OCR GCSE Chemistry Controlling reactions. Each one has a worked solution and a mark scheme showing where the marks go.