Water freezing to form ice melting a gold chain to create a gold ring breaking a window into smaller pieces these may all be classified as a) chemical change. b) physical change. c) chemical decomposition. d) increasing surface volume.

Reacting masses1 calcium carbonate breaks down on heating to produce calcium oxide and carbondioxide gas.caco3 + cao + co2a student heats 15 g of calcium carbonate strongly in a crucible.relative atomic masses (a): ca = 40, c = 12, o = 16.calculate the mass of calcium oxide produced by this reaction.(5 marks)