2025 ASRJC Prelim H1Chem P2_MS

ASRJC JC2 Prelim 2025 8873/H1 [Turn over ANDERSON SERANGOON JUNIOR COLLEGE 2025 JC 2 Preliminary Paper NAME:______________________________ ( ) CLASS: 25 / ___ CHEMISTRY 8873/02 Higher 1 27 August 2025 2 hours Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces provided at the top of this page. Write in dark blue or black pen. You may use a pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Section B Answer one question. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. Section A 1 /12 Section B 7/8 / 20 2 /9 Paper 1 / 30 3 /13 Paper 2 / 80 4 /12 Percentage Overall 5 /10 6 /4 Grade This document consists of __ printed pages and ___blank pages.

2 ASRJC JC2 Prelim 2025 8873/H1 Section A Answer all the questions in this section in the spaces provided. 1 (a) Two Period 3 elements react with an excess of oxygen at room pressure. (i) Complete Table 1.1. Table 1.1 Period 3 element Physical state of oxide at room temperature and pressure Approximate pH of solution made when oxide is added to water Na solid 13-14 S gas 1-2 [2] any two correct [1] (ii) The solutions made from oxides of sodium and sulfur of Table 1.1 are mixed together. Name the type of reaction that occurs. ……………………………….………………………………………………….[1] Acid-base or neutralisation [1] (b) Aluminium oxide, Al2O3 is amphoteric. (i) Explain what is meant by amphoteric. ……………………………………………………………………………………... …………………………………………………………………………………..[1] Reacts with both acid and bases / shows both acidic and basic behaviour. [1] (ii) Aluminium oxide is added to separate samples of dilute sulfuric acid and aqueous sodium hydroxide. Write two equations to describe the reactions that occur. ……………………………………………………………………………………... ……………………………………………………………………………………... …………………………………………………………………………………..[2] Al2O3(s) + 3H2SO4 (aq) → Al2(SO4)3(aq) + 3H2O(l) [1]

3 ASRJC JC2 Prelim 2025 8873/H1 [Turn over Al2O3(s) +2NaOH(aq) + 3H2O(l) → 2Na[Al(OH)4] (aq) [1] Ignored state symbols although we encouraged we written equations. Maximum 1 credit for correct ionic equations. (c) Chorine gas reacts with oxygen to form chlorine dioxide. When use d in small quantities, chlorine dioxide can disinfect water.