AS CHEMISTRY Paper 1 Inorganic and Physical Chemistry

AS CHEMISTRY Paper 1 Inorganic and Physical Chemistry Time allowed: 1 hour 30 minutes Materials For this paper you must have: • the Periodic Table/Data Sheet, 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 80. Advice You are advised to spend about 65 minutes on Section A and 25 minutes on Section B. Section A Answer all questions in this section. box This question is about ionisation energies of Group 2 elements. . Explain why the first ionisation energy of the Group 2 elements decreases down the group. [2 marks] . Give an equation, including state symbols, to represent the process that occurs when the third ionisation energy of magnesium is measured. [1 mark] . Explain why the third ionisation energy of magnesium is much higher than the second ionisation energy of magnesium. [2 marks] This question is about acid–base titrations. Citric acid reacts with sodium hydroxide. C6H8O7(aq) + 3 NaOH(aq) → Na3C6H5O7(aq) + 3 H2O(l) box . A student makes a solution of citric acid by dissolving some solid citric acid in water. Describe a method to add an accurately known mass of solid to a beaker to make a solution. [2 marks]