HCI Prelim P1_QP_and_Answers

This document consists of 14 printed pages. HWA CHONG INSTITUTION C2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 17S CENTRE NUMBER INDEX NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 21 September 2018 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Complete the information on the Answer Sheet as shown below. There are 30 questions on this paper. Answer all questions. For each question, there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate.

© Hwa Chong Institution 2018 9729 / 01 / C2 Prelim 2018 2 1 The successive ionisation energies, in kJ mol–1, of an element X are given below. 870 1800 3000 3600 5800 7000 13200 What can be inferred from the data provided? A X has a half-filled p-subshell. B X has a giant covalent structure. C X is likely to form a compound with the formula BeX2 when reacted with beryllium. D X has a lower first ionisation energy than the element preceding it in the Periodic Table. 2 In which pair does the first species have a larger bond angle than the second? A CF 4 and BF3 B SO2 and CO2 C ClO3– and H2S D PO43– and NO3– 3 Silicon has a giant covalent structure similar to that of diamond. At room temperature, it is a very poor conductor. However, when heated to higher temperatures, its electrical conductivity increases. What is the best explanation for the increase in electrical conductivity at higher temperatures? A Heating ionises silicon to give Si 4+ ions. B Heating increases the frequency of vibration of silicon atoms. C Heating breaks some of the Si−Si bonds, allowing silicon particles to move. D Heating excites some of the valence electrons to higher energy levels such that they can be delocalised.

© Hwa Chong Institution 2018 9729 / 01 / C2 Prelim 2018 3 4 Measured values of the pressure, volume and temperature of a known mass of a gaseous compound are to be substituted into the ideal gas equation to calculate the relative molecular mass, Mr, of the compound. Which conditions of pressure and temperature would give the most accurate value of M r? pressure temperature A low low B low high C high high D high low 5 Which graph shows the behaviour of a fixed mass of an ideal gas at two constant temperatures, T1 and T2, where T2