QTSS Prelim 2024 Sec 4Exp Chemistry P1 [6092]

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 boiling point / oC A 45 129 B 47 128 C 48 127 D 49 130

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 propanol B butanol and pentanol D pentanol and propanol

4 Queenstown Secondary School [Turn over 4 Two experimental set-ups used to demonstrate the diffusion of gases are shown in the diagrams below. In each porous pot is carbon monoxide. In the first experiment, the gas introduced into the beaker is fluorine gas, while in the second experiment, hydrogen gas was introduced. What changes, if any, to the water levels X and Y would you expect to see in both experiments? experiment 1 experiment 2 A Y is higher than X X is higher than Y B X is higher than Y Y is higher than X C X and Y remain the same Y is higher than X D X and Y remain the same X and Y remain the same 1 5 2 An ion, X2-, has a mass number of m and it contains n electrons. What does the nucleus of an atom of X contain? number of protons number of neutrons A n – 2 m – n B n – 2 m – n + 2 C n + 2 m – n + 2 D n + 2 m – n – 2

5 Queenstown Secondary School [Turn over 6 Part of the giant lattice structure of magnesium oxide and sodium chloride is shown. The structure repeats to make a giant lattice. In the giant lattice, how many negative ions directly surround each positive ion? A 3 B 4 C 5 D 6 7 The diagram shows the structural formula of the covalent molecule hydrazine, N2H4. Which row is correct? total number of electrons involved in bonding total number of electrons not involved in bonding A 5 4 B 5 8 C 10 4 D 10 8

6 Queenstown Secondary School [Turn over 8 The structures of three substances P, Q and R are shown below. P Q R Which statements are correct? 1 P and R can conduct electricity in the molten state. 2 Q is an element while P and R are compounds. 3 P has a giant structure while Q has a simple structure. A 1 and 2 B 1 and 3 C 2 and 3 D 1, 2 and 3 9 The information below shows the percentage of carbon in two samples of steel, Q and R. Q consists of 60% carbon while R consists of 20% carbon. Which statement is correct about the two samples of steel? A Q has higher strength and less brittle than R. B R has higher strength and more brittle than Q. C Q has lower strength and more brittle than R. D R has lower strength and less brittle than Q. 10 Upon strong heating, a metal nitrate compound undergoes decomposition according to the following equation: 2XNO3 (s) → 2X (s) + 2NO2 (g) + O2 (g) Complete decomposition of 3.40 g of the nitrate gives 240 cm3 of oxygen, measured at room temperature and pressure. What is the relative atomic mass of X? A 85 B 108 C 133 D 170

7 Queenstown Secondary School [Turn over 11 The structure of oxalic acid is shown. A 25.0 cm3 solution of oxalic acid reacts completely with 15.0 cm3 of 2.50 mol/dm3 aqueous sodium hydroxide. What is the concentration of the oxalic acid? A 0.750 mol/dm3 B 2.08 mol/dm3 C 1.50 mol/dm3 D 4.17 mol/dm3 12 Aspirin, C9H8O4, is made from salicylic acid, C7H6O3 according to the equation: C7H6O3 + C4H6O3 → C9H8O4 + CH3COOH Assuming a 70% yield, what is the mass of salicylic acid required to make an aspirin tablet of 325 mg? [Mr: C7H6O3, 138; C9H8O4, 180] A 174 mg B 249 mg C 356 mg D 424 mg 13 50.0 cm3 of hydrochloric acid has a pH of 1.0. This acid requires 25.0 cm3 of aqueous sodium hydroxide to be neutralised. A second 50.0 cm3 solution contains the weak acid, ethanoic acid. The hydrochloric acid and ethanoic acid have the same concentration. How will the pH of ethanoic acid and the volume of NaOH needed for neutralisation differ, if at all, from the hydrochloric acid? pH volume of NaOH needed for neutralisation A higher than HCl lower than for HCl B higher than HCl equal to HCl C lower than HCl lower than for HCl D lower than HCl equal to HCl

8 Queenstown Secondary School [Turn over 14 What is a characteristic property of all bases? A Alkalis are bases which are insoluble in water. B They dissolve in water to produce hydroxide ions. C They form salts with acids. D They react with ammonia to form ammonium salts. 15 Which statements about oxides are correct? 1 An aqueous solution of sulfur dioxide has a pH less than 7. 2 An aqueous solution of potassium oxide turns blue litmus paper red. 3 Carbon dioxide reacts with ammonia to make a salt. 4 Carbon monoxide reacts with hydrochloric acid to make a salt. A 1 and 2 B 1 and 3 C 2 and