A level OCR Chemistry Mark Scheme

Hey are scientists concerned about the release of methane gas? --CORRECT ANSWER: 1. Methanol contributes to global warming Suggest a modification to this experiment, using the same apparatus, which would reduce the percentage error in the measurements. Explain your reasoning. --CORRECT ANSWER: 1. Use a greater mass of Na2O 2. Larger temperature change to reduce percentage uncertainty The chemist finds the value of Kp is greater when the experiment is repeated at a different temperature. Explain whether the temperature is higher or lower in the second experiment (2) -- CORRECT ANSWER: 1. Temperature is lower 2. As the forward reaction is exothermic AND So, the position of equilibrium shifted to RHS Write an ionic equation for the reaction of aqueous propanoic acid with aqueous sodium carbonate --CORRECT ANSWER: 2H+ + CO3^2- —> H2CO3