2024 Prelims HCI H2 Chem P2 (QP)

This document consists of 18 printed pages and 2 blank pages. HWA CHONG INSTITUTION C2 Preliminary Examination Higher 2 CANDIDATE NAME CT GROUP 2 3 S CENTRE NUMBER S INDEX NUMBER CHEMISTRY Paper 2 Structured Questions 9729/02 28 August 2024 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, CT group, centre number and index number 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. DO NOT WRITE ON ANY BARCODES. Answer all questions in the spaces provided in the Question Paper. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. No. of sheets of writing paper submitted (if any) For Examiner’s Use 1 / 6 2 / 13 3 / 18 4 / 15 5 / 23 Deductions (s.f.) Deductions (units) Deductions (structures) Total / 75

2 © Hwa Chong Institution 2024 9729/02/C2 Preliminary Examination [Turn Over Answer all questions in the space provided. 1 (a) Complete the energy level diagram in Fig. 1.1, showing the relative energy levels of orbitals in the 3rd principal quantum shell. Fig. 1.1 [2] (b) (i) Explain what is meant by the term first ionisation energy. ……………………………………………………….……………………………………………… …………………………………………………………………………………………….……… [1] (ii) Use your knowledge of the variation in first ionisation energy of the Period 3 elements (Na to Ar) to predict and explain how the first ionisation energy varies in each pair of elements. • arsenic and selenium ……………………………………………………….……………………………………………… ……………………………………………………….……………………………………………… ……………………………………………………….……………………………………………… ……………………………………………………….……………………………………………… • bromine and krypton ……………………………………………………….……………………………………………… ……………………………………………………….……………………………………………… ……………………………………………………….……………………………………………… …………………………………………………………………………………………….………… [3] [Total: 6] energy

3 © Hwa Chong Institution 2024 9729/02/C2 Preliminary Examination [Turn Over 2 Polyfluoroalkyl substances (PFAS) is a group of compounds that have multiple fluorine atoms attached to an alkyl chain, giving these compounds waterproof properties, leading to widespread use in textiles, cosmetics, and food packaging. Poly(tetrafluoroethene), PTFE, is an early and popular example of PFAS made by polymerising tetrafluoroethene, F2C=CF2. (a) (i) State the shape and bond angle around the carbon atom in F2C=CF2. ……………………………………………………….……………………………………………... …………………………………………………………………………………………….…….. [2] (ii) Carbon atoms in F2C=CF2 are sp2 hybridised. Explain what is meant by sp2 hybridisation with reference to the carbon atom in F2C=CF2.