Conservation of mass on dissolving and heating

Not all students are confident with the idea that mass is conserved when a substance is dissolved or heated. Indeed, a number of interesting observations make the seemingly intuitive law of conservation of mass not so intuitive after all. For example, when sugar dissolves in water it disappears but mass is conserved. Use this classroom activity to help students visualise the components of a reaction using the examples of dissolving sugar and heating copper(II) carbonate.