Chemistry 5070 · O Level · Preparation of salts

Preparation of salts — practice question

(a(i))[1]

Describe the visible appearance of zinc.

(a(ii))[1]

Zinc oxide may be produced from zinc by heating it in air. Construct the equation for this reaction.

(a(iii))[1]

Which compound could be used to turn zinc oxide into zinc nitrate?

(b(i))[1]

When zinc nitrate is heated in a fume cupboard, this reaction occurs: $\text{2Zn(NO}_3\text{)}_2(s) \rightarrow \text{2ZnO}(s) + \text{4NO}_2(g) + \text{O}_2(g)$. Suggest why the heating is carried out in a fume cupboard.

(b(ii))[1]

Calculate how many moles of zinc nitrate are present in $3.78\,g$ of zinc nitrate. [$A_r$: Zn, $65$; N, $14$; O, $16$]

(b(iii))[2]

Using the reaction equation and your answer to (b)(ii), work out the volume of each gas formed when $3.78\,g$ of zinc nitrate is heated. [$1$ mole of a gas occupies a volume of $24\,000\,\text{cm}^3$ at room temperature and pressure.]

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