(a)[5]
Describe how you would prepare a pure, dry sample of barium carbonate by precipitation. Include the names of the starting materials, complete practical details, and a chemical equation.
(b(i))[2]
Write a chemical equation showing how sodium nitrate decomposes when heated.
(b(ii))[2]
Balance this chemical equation for the reaction: $2\text{Cu(NO}_3)_2 \cdot 3\text{H}_2\text{O}(s) \rightarrow \ldots \text{CuO}(s) + \ldots \text{NO}_2(g) + \text{O}_2(g) + \ldots \text{H}_2\text{O}(g)$
(b(iii))[2]
What change in colour does the anhydrous cobalt(II) chloride undergo? from [BLANK] to [BLANK].
(b(iv))[1]
How would the student test whether the water produced in (b)(iii) is pure?