Carboxylic Acids
5 marks · EasyVinegar is a dilute solution of ethanoic acid and reacts with sodium carbonate.
State the name and molecular formula of the main acid present in vinegar.
Write a balanced chemical equation for the reaction between ethanoic acid and sodium carbonate.
Calculate the maximum volume of carbon dioxide (in dm³ at room temperature and pressure) produced if 0.1 mol of sodium carbonate reacts completely with excess ethanoic acid.
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.
Show answer
(a) Ethanoic acid, molecular formula C2H4O2
(b) 2CH3COOH(aq) + Na2CO3(s) → 2CH3COONa(aq) + CO2(g) + H2O(l) · must show correct formulae and balancing, state symbols
(c) 0.1 mol Na2CO3 produces 0.1 mol CO2; at RTP, volume = 0.1 × 24 = 2.4 dm³ · must show mole to volume calculation using 24 dm³/mol
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly states 'ethanoic acid' and gives molecular formula C2H4O2
M1 (b) · 1 mark · Correct reactants and products (formulae) (follow-through)
A1 (b) · 1 mark · Chemical equation is fully balanced with correct state symbols
M2 (c) · 1 mark · Calculates moles of CO2 correctly from Na2CO3 (follow-through)
A2 (c) · 1 mark · Correct volume of CO2 calculated using 24 dm³ per mol (2.4 dm³ for 0.1 mol)
Worked solution
a) The acid in vinegar is ethanoic acid, molecular formula C2H4O2.
b) The balanced equation is:
c) 1 mol Na2CO3 gives 1 mol CO2, so 0.1 mol gives 0.1 mol CO2. Volume at RTP = 0.1 × 24 dm³ = 2.4 dm³.