MI 2018_H2_CHEM_(9729 01)_Answers Prelim

Class Adm No Candidate Name: This question paper consists of 11 printed pages and 1 blank page. 2018 Preliminary Examinations Pre-University 3 H2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 21 Sept 2018 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not turn over this question paper until you are told to do so Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and admission number in the spaces provided at the top of this page and on the Multiple Choice Answer Sheet 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 Multiple Choice Answer Sheet provided. Read the instructions on the Multiple Choice 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 question paper. The use of an approved scientific calculator is expected, where appropriate. FOR EXAMINER’S USE TOTAL (30 marks)

2 1 Use of the Data Booklet is relevant to this question. Which sample of gas below contains the same number of particles as 19.0 g of fluorine gas? 1 2.0 g of helium gas 2 10.1 g of neon gas 3 17.0 g of ammonia gas A 1 only B 3 only C 1 and 2 only D 1, 2 and 3 2 Arsenic in the form of arsenic trioxide, As 2O3, was used in the past as rat poison. To test for the presence of As2O3, 1.0 g sample containing some As 2O3 is dissolved and excess H 2S is then added to the solution. 0.492 g of As2S3 is precipitated as a result. The equation for the reaction is given below: As2O3 + 3H2S ⟶ As2S3 + 3H2O What is the percentage by mass of arsenic in the original sample? A 15.9% B 29.0% C 39.5% D 86.5% 3 Use of the Data Booklet is relevant to this question. Tin(II) ions can be used as a reducing agent. What volume of 0.025 mol dm -3 of tin(II) ions is needed to completely reduce 5 × 10-4 mol of potassium manganate(VII)? A 8.00 cm3 B 16.0 cm3 C 25.0 cm3 D 50.0 cm3

3 [Turn over 4 The graph below shows the 3 rd ionisation energies of elements A to I, which are consecutive elements with atomic number less than 20. Third ionisation energy elements Which of the following statements is correct? A The 3rd ionisation energy of B is the highest as it is the removal of an inner shell electron. B Element A is a noble gas. C Element E has a lower 3 rd ionisation energy than element D because of inter-electronic repulsion from the paired 2p electrons. D Element G has a higher 3rd ionisation energy than