2023 SAJC H2 Chem Prelim P2 (QP)

ST ANDREW’S JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATIONS HIGHER 2 CANDIDATE NAME CLASS 2 2 S CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper. Additional Materials: Data Booklet 9729/02 30 August 2023 2 hours READ THESE INSTRUCTIONS FIRST Write your name and class on all the work that 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 28 printed pages (including this cover page). For Examiner’s Use Q1 9 Q2 21 Q3 17 Q4 9 Q5 19 Total 75

2 1 (a) Table 1.1 lists the number of protons, neutrons and electrons in five different particles. Each particle may be an atom, an anion or a cation. Table 1.1 particle number of protons number of neutrons number of electrons A 17 18 17 B 17 20 17 C 17 20 18 D 18 22 18 E 18 22 17 F 19 20 19 G 19 20 18 (i) Use the information in Table 1.1 to identify • the two particles which are a pair of isotopes of the same element __________________________________________________________ • the uncharged particle with no unpaired electrons __________________________________________________________ [2] (ii) Deduce which particle, F or G is smaller. Explain your answer. [2] ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… …………………………………………………………………………………………

3 (b) Phosphorus pentachloride, PC l5, is a useful reagent in organic synthesis. It exists in equilibrium with PCl3 and chlorine gas as shown below: PCl5 (g) PCl3 (g) + Cl2 (g) ΔH = +124 kJ mol‒1 At equilibrium, at 200 °C and a total pressure of 5 atm, 40% of PC l5 is dissociated. (i) Write an expression for Kp for the above equilibrium. [1] ………………………………………………………………………………………… …. (ii) Calculate a value for Kp at 200 °C and state its units. [2] (iii) Predict and explain the effect of increasing the temperature on the value of Kp. [2] ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… [Total: 9]

4 2 (a) Table 2.1 gives data about some physical properties of the elements potassium, calcium and iron. Table 2.1 Property potassium calcium iron relative atomic mass 39.1 40.1 55.8 atomic radius (metallic) / nm 0.243 0.197 0.126 ionic radius (charge) / nm 0.138 (1+) 0.099 (2