(a) Write the formula of aluminium sulfate. [1]
(b) Balance the equation for the reduction of iron(III) oxide by carbon monoxide.
$$\text{Fe}_2\text{O}_3 + \ldots\text{CO} \rightarrow \ldots\text{Fe} + \ldots\text{CO}_2$$ [1]
(c) When solutions of silver nitrate and sodium chloride are mixed, a white precipitate of silver chloride forms.
Write the ionic equation for this reaction. Include state symbols. [2]
- (a) $\text{Al}_2(\text{SO}_4)_3$(1)
- (b) $\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$(1)
- (c) $\text{Ag}^+ + \text{Cl}^- \rightarrow \text{AgCl}$(1)
- (c) state symbols (aq) + (aq) → (s) (dependent on correct species)(1)
- Answer: (a) Al₂(SO₄)₃ (b) 3, 2, 3 (c) Ag⁺(aq) + Cl⁻(aq) → AgCl(s)
- Examiner tip: Ionic equations leave out spectator ions (Na⁺ and NO₃⁻) — including them loses the first mark.