Separate samples of 0.02 mol of calcium carbonate and 0.02 mol of barium carbonate are heated until completely decomposed to the metal oxide and carbon dioxide.

1. (a)State which of these two Group 2 carbonates requires the higher temperature before it begins to decompose. Explain your answer.[2]
2. (b)After decomposition is complete, the 0.02 mol sample of calcium oxide is taken and added to 2.00 dm³ of water. A solution is formed with no solid present. Dilute sulfuric acid is then added dropwise until a precipitate is seen. The same procedure is repeated with the 0.02 mol sample of barium oxide, using the same concentration solution of dilute sulfuric acid. Identify the sample to which most sulfuric acid must be added to cause a precipitate to appear. Explain your answer. You should refer to the solubilities of the precipitates and relevant energy terms in your answer.[3]
3. (c)(i)Calculate the mass, in g, of CO₂ produced by the decomposition of 0.020 moles of calcium carbonate.[1]
4. (c)(ii)Calculate the minimum mass, in g, of propane that would, on complete combustion, produce the same mass of CO₂ calculated in (c)(i). Give your answer to three significant figures.[2]