2024 ACJC Prelim H1 Chem Paper 2 OP

This document consists of 20 printed pages and 2 blank pages. s Anglo-Chinese Junior College JC2 Preliminary Examination Higher 1 CANDIDATE NAME FORM CLASS TUTORIAL CLASS 2CHX INDEX NUMBER CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper. Additional Materials: Data Booklet 8873/02 21 August 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your name and index number in the spaces on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions. Section B Answer one question. The use of approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiners’ use only Section A 1 / 14 2 / 10 3 / 13 4 / 10 5 / 13 Section B 6 or 7 / 20 Presentation Total / 80

2 © ACJC2024 8873/Preliminary Examination/2024 [Turn over Section A Answer all the questions in this section in the spaces provided. 1 Aqueous hydrogen peroxide, H2O2, slowly forms water and oxygen at room temperature and pressure, r.t.p. This rate of reaction is increased by the addition of a small amount of solid manganese(IV) oxide. 2H2O2(aq) 2H2O(l) + O2(g) (a) (i) Define the term, rate of reaction. ……………………………………………………………………………………………. …………………………………………………………………………………………[1] (ii) State the role of manganese(IV) oxide and explain the reason. ………………………………………………………………………………………….… …………………………………………………………………………………………[2] (iii) State the test for oxygen gas. …………………………………………………………………………………………[1] (iv) State the effect on the mass of oxygen gas produced if the mass of manganese(IV) oxide is increased. …………………………………………………………………………………………[1]

3 © ACJC2024 8873/Preliminary Examination/2024 [Turn over (b) A student investigates the rate of formation of oxygen gas when manganese(IV) oxide is added to aqueous hydrogen peroxide. The volume of oxygen gas formed is measured at regular time intervals at r.t.p. The results are plotted onto the graph in Fig. 1.1. Fig. 1.1 (i) State how the graph in Fig. 1.1 shows the rate of reaction at time t2, is lower than at time t1. …………………………………………………………………………………………[1] (ii) Explain, using collision theory, why the rate of reaction at time t2 is lower than at time t1. ………………………………………………………………………………………….… …………………………………………………………………………………………[2] (iii) On Fig. 1.1, sketch the graph obtained when the experiment is repeated using aqu