2020 SAJC H2 Prelim Paper 2 (Answers)

1 [Turn over ST ANDREW’S JUNIOR COLLEGE JC2 Preliminary Examinations Higher 2 CANDIDATE NAME CLASS 1 9 S CHEMISTRY Paper 2 Structured Questions Candidate answer on the Question Paper. Additional Materials: Data Booklet 9729/02 2 September 2020 2 hours READ THESE INSTRUCTIONS FIRST Write your name and class on all the work you hand in. Write in dark blue or black pen. You may use a HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of ?? printed pages and ? blank page. For Examiner’s Use Q1 15 Q2 9 Q3 15 Q4 19 Q5 17 Total 75

2 [Turn over Answer all questions in the spaces provided. 1 (a) (i) On the axis below, sketch a graph to show the eleven ionisation energies for sodium. Explain the following features shown in your graph  the general trend in ionisation energy  significant change in values between ionisation energies ionisation energy 1 2 3 4 5 6 7 8 9 10 11 number of electrons removed

3 [Turn over ionisation energy IE generally increases as it is more difficult/more energy required to remove an e from an increasingly positively charged species. There are 2 large increase in IE. The next electron is removed form an inner shell which is closer to the nucleus. Hence, it experiences stronger nuclear attraction and more energy is required to remove it. (ii) State one similarity and one difference (other than difference in energy) between the lowest and highest energy occupied orbital in sodium. Similarity Difference [1] Similarity: spherical shape OR both are s orbitals Difference: Orbital from outermost shell/highest energy occupied orbital is more diffuse/larger OR orbital from innermost shell/lowest energy occupied orbital is less diffuse/smaller. 1 2 3 4 5 6 7 8 9 10 11 number of electrons removed

4 [Turn over (b) (i) State two factors that affect the behaviour of beams of positively charged particles in an electric field. …………………………………………………………………………………………… [1] Charge and mass (ii) On the diagram below, show how a beam of particles containing sodium ions, copper atoms and electrons deflects as they pass through an electric field at the same speed. Label your answer clearly. [2] (c) Sodium and tert-butanol reacts to give sodium tert-butoxide and hydroge