RI 2020 Y5 Timed Practice QP

1 © Raffles Institution 2020 9729/J/20 [Turn Over RAFFLES INSTITUTION 2020 Year 5 Term 3 Timed Practice HIGHER 2 CHEMISTRY 9729 26 June 2020 2 hours 15 minutes Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST DO NOT open this booklet until you are told to do so. Write your name, 6-digit exam index number and civics tutorial group in the spaces provided on the OMR Answer Sheet and the cover sheet on page 9. Shade in your 6-digit exam index number on the OMR Answer Sheet. This paper consists of three sections A, B and C. Section A (15 marks) consists of 15 multiple-choice questions. Record your answers to this section in soft pencil on the separate OMR A nswer Sheet. Your OMR Answer Sheet will be collected after the first 30 minutes. Section B (30 marks) consists of 3 structured questions. Answers to this section are to be written in the spaces provided in the question paper. Section C (35 marks) consists of 2 free-response questions. Answers to this section are to be written in the spaces provided in the question paper. You are reminded of the need for good English and clear presentation in your answers. The number of marks is given in brackets [ ] at the end of each question or part question. Write in dark blue or black pen. You may be subject to penalty for writing answers in pencil. This document consists of 25 printed pages and 0 blank page.

2 © Raffles Institution 2020 9729/J/20 [Turn Over Section A (15 marks) For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Which statement is correct? A The molar mass of a compound has the same units as its relative molecular mass. B One mole of a compound contains the same number of atoms as there are atoms in 12.0 g of carbon-12. C The relative atomic mass of fluorine is given by the following expression. weighted average mass of 1 molecule of fluorine 1 12 x mass of 1 atom of carbon-12 D 12.0 dm3 of oxygen gas contains the number of atoms as 24.0 dm3 of argon at room temperature and pressure. The following information is relevant for Questions 2 and 3. The reaction between urea, N2H4CO, and nitrous acid, HNO2, produces water, carbon dioxide gas and nitrogen gas. N2H4CO(aq) + 2HNO2(aq) → 3H2O(l) + CO2(g) + 2N2(g) 2 What is the change in the oxidation number of nitrogen fro m nitrous acid to nitrogen gas? A –1 B –3 C +3 D +5 3 In an experiment, 1 mol of urea was reacted with nitrous acid. The mass of unreacted urea was 6.0 g. What was the percentage of urea reacted? A 87.5% B 89.7% C 90.0% D 90.3%

3 © Raffles Institution 2020 9729/J/20 [Turn Over 4 The first six successive ionisation energies of an element Q are plotted in the following diagram.