This question is about the self-ionisation of water and the ionic product, KwK_wKw.
Write an expression for the ionic product of water, KwK_wKw.
At 80∘C80^\circ\text{C}80∘C, the value of KwK_wKw is 2.51×10−13 mol2 dm−62.51 \times 10^{-13}\text{ mol}^2\text{ dm}^{-6}2.51×10−13 mol2 dm−6.
Calculate the pH of pure water at 80∘C80^\circ\text{C}80∘C. Give your answer to 2 decimal places.
Explain why water is neutral at 80∘C80^\circ\text{C}80∘C.
At 25∘C25^\circ\text{C}25∘C, a solution is prepared by mixing 40.00 cm340.00\text{ cm}^340.00 cm3 of 0.180 mol dm−30.180\text{ mol dm}^{-3}0.180 mol dm−3 potassium hydroxide solution with 30.00 cm330.00\text{ cm}^330.00 cm3 of 0.140 mol dm−30.140\text{ mol dm}^{-3}0.140 mol dm−3 nitric acid.
Calculate the pH of the resulting mixture at 25∘C25^\circ\text{C}25∘C (where Kw=1.00×10−14 mol2 dm−6K_w = 1.00 \times 10^{-14}\text{ mol}^2\text{ dm}^{-6}Kw=1.00×10−14 mol2 dm−6). Give your answer to 2 decimal places.
77 exam-style questions on AQA A Level Chemistry Acids and bases (A-level only), covering Brønsted–Lowry acid–base equilibria in aqueous solution (A-level only), Definition and determination of pH (A-level only), The ionic product of water, $K_w$ (A-level only), Weak acids and bases $K_a$ for weak acids (A-level only), pH curves, titrations and indicators (A-level only), and Buffer action (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.