A student weighs a sealed tube containing copper carbonate. The tube is heated until the copper carbonate has reacted completely, allowed to cool and then weighed again. The two balance readings are the same.
Which change would cause the second balance reading to be lower than the first?
Put more copper carbonate in the sealed tube
Heat the copper carbonate in an open tube
Use a higher-resolution balance for both readings
Use a larger sealed tube containing the same mass
95 exam-style questions on AQA GCSE Chemistry 3.1 Chemical measurements, conservation of mass and the quantitative interpretation of chemical equations, covering 3.1.1 Conservation of mass and balanced chemical equations, 3.1.2 Relative formula mass, 3.1.3 Mass changes when a reactant or product is a gas, and 3.1.4 Chemical measurements. Each one has a worked solution and a mark scheme showing where the marks go.