QTSS Prelim 2024 Sec 4Exp Chemistry P1 [6092]_Ans

This document consists of 21 printed pages. Name: ………………………………………………….. ( ) Class: Sec 4 SG 1 / 2 Queenstown Secondary School Preliminary Examination 2024 Secondary Four Express Chemistry 6092/01 28 August 2024 Time: 1145 – 1245h Wednesday Duration: 1 hour Setter: Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and index number on the Answer Sheet in the spaces 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 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. A copy of the Periodic Table is printed on page 21. The use of an approved scientific calculator is expected, where appropriate.

2 Queenstown Secondary School [Turn over 1 The reaction of manganate(VII) ions with ethanedioate ions in acid solution may be represented by the following equation. 2MnO4- (aq) + 16H+ (aq) + 5C2O42- (aq) → 2Mn2+ (aq) + 8H2O (l) + 10CO2 (g) A student is exploring various ways to measure the rate of the reaction by measuring changes in different variables of the reaction. Which of the following methods of monitoring the rate of reaction are suitable? 1 volume of gas produced ✓ 2 pH of the reaction mixture ✓ 3 mass of the reaction mixture ✓ 4 amount of precipitate obtained  5 intensity of the purple colour of the reaction mixture ✓ A 1, 2 and 3 B 1, 3 and 4 C 1, 2, 3 and 5 D 2, 3, 4 and 5 2 The heating curve of an impure sample of substance X is shown below. What are the melting point and boiling point of pure substance X? melting point / oC [above] boiling point / oC [below] A 45 129 B 47 128 C 48 127 D 49 130 Mixtures will melt below the initial melting point. Mixtures will boil above the initial boiling point.

3 Queenstown Secondary School [Turn over 3 A student carried out an experiment using the set-up shown below to separate a mixture containing four alcohols. The table gives the boiling points of the four alcohols used. alcohol butanol ethanol pentanol propanol boiling point / oC 117 79 138 97 Despite repeated attempts, the student only managed to obtain two alcohols from the mixture. Which alcohols did he fail to obtain? A butanol and ethanol C ethanol and pro