2021_TJC_H2Chemistry_P1 Prelim

1 9729 / TJC Prelim / 2021 [Turn Over TEMASEK JUNIOR COLLEGE 2021 JC2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9729/01 15 September 2021 1 hour Additional Materials: Multiple Choice Answer Sheet (OMS) Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, Class and index number on the Answer Sheet in the spaces provided. There are thirty 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 separate 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. This document consists of 15 printed pages and 1 blank page. Write your name and Civics Group Write and shade your index number

2 9729 / TJC Prelim / 2021 [Turn Over 1 One diatomic molecule of an element E has an average mass of 1.18 x 10–22 g. E reacts with ethene to form C2H4E2. How many E atoms are there in 49.5 g of C2H4E2? A 1.75 x 1023 B 3.01 x 1023 C 3.50 x 1023 D 6.02 x 1023 2 The radioactive isotope decays to give an element Q and emits a high energy α-particle (which is a helium nucleus,). No other particle is produced. Q + How many neutrons are present in element Q? A 219 B 135 C 133 D 86 3 Lecithin is an emulsifier added to chocolate to help bind the cocoa solids, sugar and milk so they stick to the cocoa butter. Its structure is shown below. R: long hydrophobic carbon chains Which of the following statements about lecithin is correct? A It can form instantaneous dipole-induced dipole interactions with non-polar molecules present in chocolate. B It can form hydrogen bonds between its own molecules. C All bond angles surrounding each carbon atom are 109.5°. D It does not contain delocalised electrons. Ra22 3 88 He4 2 Ra22 3 88 He4 2

3 9729 / TJC Prelim / 2021 [Turn Over 4 Cholesterol is a waxy substance that is present in blood plasma and in all animal tissues. Cholesterol Which of the following statements about cholesterol are incorrect? 1 All the seventeen carbon atoms in the four rings lie in the same plane. 2 It can exhibit cis–trans isomerism at the C=C double bond. 3 It is acidic. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 5 A sample of an organic compound of molar mass M is vapourised in a gas syringe and occupies V cm3 at T K and p Pa. What is the density of the compound? A p×M×273T×10!×22700 B p×M×293T×10!×24000 C p×M×10!×22700T×273 D p×M×273T×22700

4 9729 / TJC Prelim / 2021 [Turn Over 6 Which graphs correctly describe the behaviour of a fixed mass of an ideal gas (where T is measured in K)? 1 2 3