Reaction with metals
5 marks · HardA solution of ethanoic acid is reacted with calcium carbonate (CaCO₃) powder in a test-tube.
State one observation you would make during the reaction.
Write a balanced symbol equation for the reaction.
Name the salt formed.
Ethanoic acid reacts more slowly than hydrochloric acid of the same concentration. Explain why.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) Effervescence (fizzing) / bubbles of gas
(b) CaCO3(s) + 2CH3COOH(aq) → (CH3COO)2Ca(aq) + CO2(g) + H2O(l) · must show balanced equation, correct formulae
(c) Calcium ethanoate
(d) Ethanoic acid is a weak acid so it only partially ionises, producing fewer hydrogen ions for the reaction.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States an appropriate observation such as 'fizzing', 'effervescence', or 'bubbles of gas'.
M1 (b) · 1 mark · Writes correct formulae for the reactants and products.
A1 (b) · 1 mark · Gives a fully balanced symbol equation.
B2 (c) · 1 mark · Names the salt as calcium ethanoate.
B3 (d) · 1 mark · Explains that ethanoic acid is a weak acid that only partially ionises, producing fewer hydrogen ions than hydrochloric acid.
Worked solution
a) Observation: Fizzing or effervescence, as carbon dioxide gas is produced.
b) Symbol equation shown above.
c) The salt formed is calcium ethanoate.
d) Ethanoic acid is a weak acid and only partially ionises, producing fewer hydrogen ions for reaction than strong acids like hydrochloric acid.