An analytical chemist investigated a sample of partially effloresced sodium carbonate crystals (Na2CO3⋅xH2O\text{Na}_2\text{CO}_3 \cdot x\text{H}_2\text{O}Na2CO3⋅xH2O) retrieved from an old laboratory store.
The chemist added 1392 mg1392\text{ mg}1392 mg of this hydrated sodium carbonate to 50.0 cm350.0\text{ cm}^350.0 cm3 of 0.500 mol dm−30.500\text{ mol dm}^{-3}0.500 mol dm−3 hydrochloric acid in a beaker and stirred the mixture to ensure complete reaction.
Once the reaction had finished, the resulting solution was quantitatively transferred to a volumetric flask, made up to 250 cm3250\text{ cm}^3250 cm3 with deionised water and mixed thoroughly.
The chemist titrated 25.0 cm325.0\text{ cm}^325.0 cm3 portions of this diluted solution against 0.100 mol dm−30.100\text{ mol dm}^{-3}0.100 mol dm−3 aqueous sodium hydroxide. The mean titre obtained was 13.00 cm313.00\text{ cm}^313.00 cm3 of the sodium hydroxide solution.
Calculate the value of xxx in Na2CO3⋅xH2O\text{Na}_2\text{CO}_3 \cdot x\text{H}_2\text{O}Na2CO3⋅xH2O.
Show your working.
Give your answer as an integer.
79 exam-style questions on AQA A Level Chemistry Amount of substance, covering Relative atomic mass and relative molecular mass, The mole and the Avogadro constant, The ideal gas equation, Empirical and molecular formula, and Balanced equations and associated calculations. Each one has a worked solution and a mark scheme showing where the marks go.