CJC 2024 Prelim H1 Chem Paper 1 QP

1 CHEMISTRY 8873/01 Paper 1 Multiple Choice 12 September 2024 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, HT group and NRIC/FIN number on the Answer Sheet in the spaces provided. Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. 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 13 printed pages Catholic Junior College JC 2 Preliminary Examinations Higher 1

2 8873/01/CJC JC2 Preliminary Examination 2024 For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 A sample of bromine contains a mixture of two isotopes, 79Br and 81Br. The relative atomic mass of Br in this sample is 79.92. What is the percentage abundance of each isotope? 79Br 81Br A 46.0% 54.0% B 41.2% 58.8% C 54.0% 46.0% D 58.8% 41.2% 2 Use of Data Booklet is relevant to this question. How many atoms of silver (proton number 47) are there in a pure silver ring with a mass of 2.88 g? A 1.20 x 1021 C 1.20  1022 B 2.00 x 1021 D 1.61  1022 3 In an experiment, 100 cm3 of a 0.2 mol dm−3 solution of a metallic salt reacts exactly with 50 cm3 of 0.2 mol dm−3 aqueous sodium sulfite, Na2SO3. The half-equation for the oxidation of the sulfite ion is shown below: SO 2– 3 (aq) + H2O(l) → SO 2– 4 (aq) + 2H+(aq) + 2e− If the original oxidation number of the metal ion for the metallic salt is +3, what is the new oxidation number of the metal ion? A +1 B +2 C +4 D +5

3 8873/01/CJC JC2 Preliminary Examination 2024 [Turn over 4 A and B represent two consecutive elements in the periodic table. A2+ contains n protons while the cation of B contains (n+1) protons and is isoelectronic with A. What is the formula of the chloride formed by B? A BCl B BCl2 C BCl3 D BCl4 5 Which of the following is the correct electronic configuration of a c opper(II), Cu2+ ion in the ground state? A 1s2 2s2 2p6 3s2 3p6 3d9 4s2 B 1s2 2s2 2p6 3s2 3p6 3d10 4s1 C 1s2 2s2 2p6 3s2 3p6 3d10 D 1s2 2s2 2p6 3s2 3p6 3d9 6 Which of the following gives the symbols of elements in the order of decreasing first ionisation energy? A Cl, Br, I B F, Ne, Na C Al, Mg, Na D Cl, S, P 7 Which of the following have giant lattice structures under standard conditions at 298 K? 1 magnesium 2 buckminste