HCI_H2_CHEM_P1 Prelim

This document consists of 20 printed pages. HWA CHONG INSTITUTION C2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 13S CENTRE NUMBER INDEX NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Optical Mark Sheet (OMS) Data Booklet 9647/01 25 September 2014 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Complete the information on the optical mark sheet (OMS) as shown below. There are forty 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 OMS. 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. Write your name Write and shade your NRIC or FIN number Write your CT group

2 © Hwa Chong Institution 2014 9647 / 01 / C2 Prelim 2014 SECTION A 1 Consider the following half equations. MnO4  + 8H+ + 5e  Mn2+ + 4H2O C2O4 2  2CO2 + 2e To determine the concentration of Ca 2+ ions in river water sample, 1.00 cm 3 of the water sample was first treated with excess aqueous Na 2C2O4. The CaC 2O4 precipitate formed was filtered and treated with dilute aqueous H 2SO4. The C 2O4 2 ions released into the solution required 10.00 cm3 of 2.00  10–5 mol dm–3 acidified KMnO4 for complete reaction. What was the concentration of Ca2+ in the river water sample? A 5.00  10–4 mol dm–3 B 8.00  10–5 mol dm–3 C 5.00  10–7 mol dm–3 D 8.00  10–8 mol dm–3 2 Chromium has four naturally occurring stable isotopes: 50Cr, 52Cr, 53Cr, and 54Cr. Which statement about its ions is correct? A 52Cr3+ ion has less protons than 54Cr3+ ion. B The electronic configuration of 52Cr3+ ion is 1s22s22p63s23p63d24s1. C The electronic configurations of 52Cr3+ ion and 53Cr3+ ion are different. D 50Cr3+ ion shows a greater angle of deflection than 52Cr3+ ion in an electric field. 3 The successive ionisation energies of two elements, P and Q, are given below. Ionisation energies / kJ mol−1 1st 2nd 3rd 4th 5th 6th 7th 8th P 740 1450 7720 10540 13630 18020 21700 25660 Q 1011 1907 2910 4960 6270 21270 25431 29872 What is the formula of the compound formed when P reacts with Q? A P2Q3 B P3Q2 C P2Q5 D P5Q2

3 © Hwa Chong Institution 2014 9647 / 01 / C2 Prelim 2014 4 In an experiment, 2.0 g of a gas Y at 273 C was found to occupy the same volume as 1.5 g of nitrogen gas at 298 C. Both gases were at the same pressure. What is the relative molecular mass of the gas Y? A 2985.1 282730.2   B 2730.2 282985.1   C )273298(5.1 28)273273(0.2   D )273273(0.2 28)273298(5.1   5 The Ellingham diagram plots the free energy change of a reaction as a function of t