2025 JC2 Prelims H2 Chem Paper 2 QP_TJC

9729 / TJC Prelims / 2025 DO NOT WRITE IN THIS MARGIN [Turn over TEMASEK JUNIOR COLLEGE 2025 JC2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS / 24 CENTRE NUMBER S INDEX NUMBER Chemistry 9729/02 Paper 2 Structured Questions 3 September 2025 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, CG, centre and index number in the space provided at the top of this page. Write in dark blue or black pen. You may use an 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. The number of marks is given in bracket [ ] at the end of each question or part question. This document consists of 22 printed pages and 2 blank pages. For Examiner’s Use Q1 Q2 Q3 Q4 Q5 Q6 Total

2 DO NOT WRITE IN THIS MARGIN 9729 / TJC Prelims / 2025 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 1 In 1932, the American chemist Linus Pauling developed the most common scale of relative electronegativity (EN) values for the elements. The Pauling EN values of elements can be used to predict the chemical properties of compounds. The EN values of four Period 3 elements are given in Table 1.1. Table 1.1 Element Sodium Aluminium Phosphorus Chlorine Pauling EN value 0.93 1.61 2.19 3.16 l (a) (i) Explain the difference in the Pauling electronegativity values of Na and Cl. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .....................................................................................................................................[2] The ionic character of a bond is directly related to the electronegativity difference ( EN) between the bonded atoms. Fig. 1.1 shows the plot of percent ionic character against EN for NaCl. Fig. 1.1 (ii) Using the values in Table 1.1, calculate EN for AlCl3 and PCl5 respectively. Hence plot the percent ionic character of AlCl3 and PCl5 on Fig. 1.1. Label your points clearly. [2]

3 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 9729 / TJC Prelims / 2025 DO NOT WRITE IN THIS MARGIN [Turn over (iii) Explain the difference in bonding for NaCl and PCl5 in terms of electroneg