MI Prelim 9647_P1_Answers

Class Adm No Candidate Name: This question paper consists of 16 printed pages and 2 blank pages. 2017 Preliminary Examinations II Pre-University 3 H2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 20 Sept 2017 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 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 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 (40 marks)

2 Section A For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Dolomite is a carbonate-containing mineral with formula MgZ(CO3)2 where Z is a metal ion. It is insoluble in water but reacts with acids. When 2.00 g of dolomite was completely dissolved in an excess of hydrochloric acid, 0.759 g of carbon dioxide was given off. What is the identity of the metal Z? A Ba B Ca C Ra D Sr 2 Sulfur dioxide gas is an irritant to the eyes and respiratory system. The maximum safe toleration level of sulfur dioxide in air is 0.014 mg dm-3. How many molecules of sulfur dioxide gas are present in 1 dm3 of air at this toleration level? A 0.014 6.02 × 1023 × 64.1 B 0.014 1000 × 1 64.1 × 6.02 × 1023 C 0.014 64.1 × 6.02 × 1023 D 0.014 1000 × 64.1 × 6.02 × 1023 3 The element technetium, Tc (mass number 99; atomic number 43), was discovered in 1937 by two Italian scientists, Segŕe and Perrier. Under suitable conditions, technetium reacts with fluorine to form TcF6. Which of the following options shows the correct number of protons, neutrons and electrons in Tc6+? number of protons number of neutrons number of electrons A 43 43 56 B 43 56 37 C 49 43 37 D 43 56 49

3 [Turn over 4 Which of the following atoms has three unpaired electrons? A Br B Co C Ga D Sc 5 Under standard conditions, water exists in the liquid state but hydrogen sulfide exists in the gaseous state. Which of the following best explains this phenomenon? A Water has a higher relative molecular ma