Chemistry 9701 · AS & A Level · Group 2

Group 2 — practice question

When heated, both calcium carbonate, $\text{CaCO}_3$, and barium carbonate, $\text{BaCO}_3$, break down to produce a metal oxide and a gas.
(a)[1]

Write an equation to show the thermal decomposition of $\text{CaCO}_3$.

(b)[2]

State which one of $\text{CaCO}_3$ and $\text{BaCO}_3$ decomposes at a lower temperature. Explain your answer.

(c(i))[1]

Calcium oxide, $\text{CaO}$, reacts with water to produce compound A. Barium oxide, $\text{BaO}$, reacts with water to produce compound B. Identify A.

(c(ii))[3]

Explain why A has a lower solubility than B.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: Balanced equation: $\mathrm{CaCO_3 \rightarrow CaO + CO_2}$

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