This question is about acids, bases and salts.
What is the pH of 2.50 dm32.50\text{ dm}^32.50 dm3 of 0.200 mol dm−30.200\text{ mol dm}^{-3}0.200 mol dm−3 of KOH(aq)\text{KOH(aq)}KOH(aq) at 298 K298\text{ K}298 K?
[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 at 298 K298\text{ K}298 K]
Water is added to 15.0 cm315.0\text{ cm}^315.0 cm3 of 0.800 mol dm−30.800\text{ mol dm}^{-3}0.800 mol dm−3 HNO3(aq)\text{HNO}_3\text{(aq)}HNO3(aq) to produce 500 cm3500\text{ cm}^3500 cm3 of diluted HNO3(aq)\text{HNO}_3\text{(aq)}HNO3(aq).
What is the pH of the diluted HNO3(aq)\text{HNO}_3\text{(aq)}HNO3(aq)? Give your answer to 2 decimal places.
A buffer solution has concentrations of 0.250 mol dm−30.250\text{ mol dm}^{-3}0.250 mol dm−3 CH3CH2COOH(aq)\text{CH}_3\text{CH}_2\text{COOH(aq)}CH3CH2COOH(aq) and 0.150 mol dm−30.150\text{ mol dm}^{-3}0.150 mol dm−3 CH3CH2COONa(aq)\text{CH}_3\text{CH}_2\text{COONa(aq)}CH3CH2COONa(aq).
KaK_aKa for CH3CH2COOH=1.35×10−5 mol dm−3\text{CH}_3\text{CH}_2\text{COOH} = 1.35 \times 10^{-5}\text{ mol dm}^{-3}CH3CH2COOH=1.35×10−5 mol dm−3 at 298 K298\text{ K}298 K.
What is the pH of the solution at 298 K298\text{ K}298 K? Give your answer to 2 decimal places.
A student is provided with hydrated nickel(II) sulfate, NiSO4⋅6H2O\text{NiSO}_4 \cdot 6\text{H}_2\text{O}NiSO4⋅6H2O.
The student needs to prepare a standard solution of NiSO4⋅6H2O\text{NiSO}_4 \cdot 6\text{H}_2\text{O}NiSO4⋅6H2O with a concentration of 0.150 mol dm−30.150\text{ mol dm}^{-3}0.150 mol dm−3. Describe how the student would prepare 250.0 cm3250.0\text{ cm}^3250.0 cm3 of this solution, giving quantities, apparatus and method.
[Use molar masses: Ni=58.7 g mol−1\text{Ni} = 58.7\text{ g mol}^{-1}Ni=58.7 g mol−1, S=32.1 g mol−1\text{S} = 32.1\text{ g mol}^{-1}S=32.1 g mol−1, O=16.0 g mol−1\text{O} = 16.0\text{ g mol}^{-1}O=16.0 g mol−1, H=1.0 g mol−1\text{H} = 1.0\text{ g mol}^{-1}H=1.0 g mol−1]
