A-level CHEMISTRY 7405/1 Paper 1 Inorganic and Physical Chemistry Question Paper + Mark scheme [MERGED] June 2024

A-level CHEMISTRY Paper 1 Inorganic and Physical Chemistry Time allowed: 2 hours Materials For this paper you must have: • the Periodic Table/Data Booklet, provided as an insert (enclosed) • a ruler with millimetre measurements • a scientific calculator, which you are expected to use where appropriate. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • All working must be shown. • Do all rough work in this book. Cross through any work you do not want to be marked. Information • The marks for questions are shown in brackets. • The maximum mark for this paper is 105. DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 0 1 This question is about equilibria. 0 1 . 1 Give two features of a reaction in dynamic equilibrium. [2 marks] Feature 1 Feature 2 0 1 . 2 A gas-phase reaction is at equilibrium. When the pressure is increased the yield of product decreases. State what can be deduced about the chemical equation for this equilibrium. [1 mark] Question 1 continues on the next page Turn over ► 0 1 . 3 Carbon monoxide and hydrogen react to form methanol. CO(g) + 2 H2(g) ⇌ CH3OH(g) 0.430 mol of carbon monoxide is mixed with 0.860 mol of hydrogen. At equilibrium, the total pressure in the flask is 250 kPa and the mixture contains 0.110 mol of methanol. Calculate the amount, in moles, of carbon monoxide present at equilibrium. Calculate the partial pressure, in kPa, of carbon monoxide in this equilibrium mixture. [3 marks] Amount of carbon monoxide mol Partial pressure kPa 0 1 . 4 Give an expression for the equilibrium constant (Kp) for this reaction. CO(g) + 2 H2(g) ⇌ CH3OH(g) [1 mark] Kp 0 1 . 5 A different mixture of carbon monoxide and hydrogen is left to reach equilibrium at a temperature T. Some data for this equilibrium are shown in Table 1. Table 1 Partial pressure of CO 125 kPa Partial pressure of CH3OH 5.45 kPa Kp 1.15 x 10–6 kPa–2 CO(g) + 2 H2(g) ⇌ CH3OH(g) Calculate the partial pressure, in kPa, of hydrogen in this equilibrium mixture. [3 marks] Partial pressure kPa Turn over ►