A student heated 10.0 g of hydrated copper sulfate crystals in an open evaporating basin. Water vapour was given off. The mass of the solid left in the basin was 6.4 g. Which statement about this experiment is correct?
3.6 g3.6\ \text{g}3.6 g of water was given off, and the total mass of all the substances is unchanged.
3.6 g3.6\ \text{g}3.6 g of water was given off, and the total mass of all the substances has decreased.
6.4 g6.4\ \text{g}6.4 g of water was given off, and the total mass of all the substances is unchanged.
6.4 g6.4\ \text{g}6.4 g of water was given off, and the total mass of all the substances has decreased.
40 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.