Chemistry 0620 · IGCSE · The characteristic properties of acids and bases

The characteristic properties of acids and bases — practice question

Ethanoic acid is a weak acid, whereas hydrochloric acid is a strong acid. In aqueous solution, both ethanoic acid and hydrochloric acid dissociate.
(a(i))[1]

Define acid.

(a(ii))[2]

The equation below shows what happens when the strong acid hydrochloric acid is mixed with water. $\text{HCl}(aq) \rightarrow \text{H}^+(aq) + \text{Cl}^-(aq)$ Complete the equation to show what happens when the weak acid ethanoic acid is mixed with water. $\text{CH}_3\text{COOH}(aq)$ ............

(b(i))[2]

State two observations that would indicate hydrochloric acid is stronger than ethanoic acid.

(b(ii))[3]

State three additional conditions that must stay the same for a fair test.

(c)[4]

Calculate the mass, in g, of magnesium carbonate required to react completely with $50.00\,\text{cm}^3$ of $2.00\,\text{mol dm}^{-3}$ hydrochloric acid by following the steps below.

(d(i))[1]

Why does the student use excess magnesium carbonate?

(d(ii))[1]

Why is the residue rinsed?

(d(iii))[3]

Describe how the student would obtain pure magnesium chloride crystals from the filtrate.

(e(i))[2]

What does the term precipitate mean?

(e(ii))[3]

Name a suitable silver salt for making silver chloride. Finish the chemical equation to show how insoluble silver chloride forms from aqueous barium chloride and the aqueous silver salt you have named. $\text{BaCl}_2 +$ ............ $\rightarrow$ ............ + ............

Worked solution & mark scheme

This 22-mark question has a full step-by-step worked solution and mark scheme. One marking point: proton-donating species

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