HCI_H2_CHEM_P1_ANSWERS Prelim

This document consists of 14 printed pages. HWA CHONG INSTITUTION JC2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 10S CENTRE NUMBER INDEX NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9647/01 23 September 2011 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 2011 9647 / 01 / JC2 Prelim 2011 Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 Mixtures of argon and another gas are commonly used during welding. One such gaseous mixture has a density of 1.82 g dm −3 at s.t.p. What could be the other gas in this mixture? [Density of argon = 1.78 g dm −3 at s.t.p.] A Carbon dioxide B Oxygen C Nitrogen D Helium 2 X is an organic iron compound containing only Fe, C and H. When a 0.944 g sample of X was subjected to complete combustion, 2.23 g of CO2 and 0.457 g of H2O were formed. What is the empirical formula of X? A FeCH B FeC 2H C Fe2C5H2 D FeC10H10 3 Some isotopes are unstable and undergo nuclear (radioactive) reactions. In one type of reaction, an unstable nucleus assimilates an electron from an inner orbital of its electron cloud. The net effect is the conversion of a proton and an electron into a neutron. Which of the following describes this type of reaction? A 11C  12C B 111I  111Te C 76Br  75Br D 76Kr  75Br 4 In which of the following pairs does the first substance have a higher melting point than the second? First substance Second substance A CH3CH2OCH3 CH 3CH2NHCH3 B (CH3)3CH CH 3CH2CH2CH3 C RbCl KC l D C O OH OH C O OH OH

3 © Hwa Chong Institution 2011 9647 / 01 / JC2 Prelim 2011 5 A fixed amount of an ideal gas is contained in a frictionless gas syringe. For a period of t seconds, the volume of the syringe is increased at a constant rate. The temperature within the syringe is constant throughout. Which of the following graphs correctly shows how the pressure in the syringe changes within the t seconds? A B C D 6 When water vaporizes, 40.7 kJ mol1 of heat enthalpy is required. What is the entropy c