An analytical chemist prepared 500 cm3500\text{ cm}^3500 cm3 of a standard solution of citric acid (C6H8O7\text{C}_6\text{H}_8\text{O}_7C6H8O7) with a concentration of 0.0250 mol/dm30.0250\text{ mol/dm}^30.0250 mol/dm3.
Calculate the mass of citric acid required to prepare this solution.
Relative atomic masses (ArA_rAr): extH=1 ext{H} = 1extH=1; extC=12 ext{C} = 12extC=12; extO=16 ext{O} = 16extO=16.
During a titration, 20.0 cm320.0\text{ cm}^320.0 cm3 of the 0.0250 mol/dm30.0250\text{ mol/dm}^30.0250 mol/dm3 citric acid solution was found to neutralise exactly 30.0 cm330.0\text{ cm}^330.0 cm3 of a sodium hydroxide solution of unknown concentration.
The balanced equation for this neutralisation reaction is:
3NaOH+C6H8O7→Na3C6H5O7+3H2O3\text{NaOH} + \text{C}_6\text{H}_8\text{O}_7 \rightarrow \text{Na}_3\text{C}_6\text{H}_5\text{O}_7 + 3\text{H}_2\text{O}3NaOH+C6H8O7→Na3C6H5O7+3H2O
Calculate the concentration of the sodium hydroxide solution in 0.0250 mol/dm30.0250\text{ mol/dm}^30.0250 mol/dm3.
Practise AQA GCSE Chemistry Reactions of acids with exam-style questions for Foundation and Higher tier. 43 questions covering Reactions of acids with metals, Neutralisation of acids and salt production, Soluble salts, The pH scale and neutralisation, Titrations (chemistry only), and Strong and weak acids (HT only), matched to the AQA GCSE Chemistry (8462) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.