2022 TMS Chem Prelims P1

TEMASEK SECONDARY SCHOOL Preliminary Examination 2022 Secondary 4 Express CHEMISTRY 6092/01 Paper 1 1 hour Question Booklet Additional Material: OTAS READ THESE INSTRUCTIONS FIRST Do not open the booklet until you are told to do so. Write your name, index number and class on the Optical Answer Sheet. Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. You are not required to hand in this booklet at the end of the examination. 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 OTAS. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done on this booklet. A copy of the Periodic Table is printed on page 17. This document consists of 17 printed pages and 1 blank page. ���

2 No part of the paper is to be reproduced without the approval of the Principal of Temasek Secondary School. 2 When a covalent liquid boils, its molecules become more widely spaced. Which property of the molecules has the most influence on the energy required to boil a covalent liquid? A the strength of the forces of attraction between the molecules B the reactivity of the molecules C the shape of the molecules D the strength of the covalent bonds in the molecules 3 In which particle are the number of protons, neutrons and electrons all different? 1 Hexane and octane are liquid hydrocarbons that mix together. Which apparatus is used to separate a mixture of these two liquids? A B C D - + 2+ ���

3 No part of the paper is to be reproduced without the approval of the Principal of Temasek Secondary School. 4 A student is provided with two drying agents: concentrated sulfuric acid an d calcium oxide. Which method should he use to collect a sample of dry ammonia? A B C D 5 Silicon carbide, SiC, has a structure similar to diamond. Boron nitride, BN, has a structure similar to graphite. Bronze is an alloy of copper and tin. Which statements about SiC, BN and bronze are correct? 1 All are bonded covalently. 2 All have a giant structure. 3 All have high melting points. A 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3 ���

4 No part of the paper is to be reproduced without the approval of the Principal of Temasek Secondary School. 6 Some car paints contain small flakes of silicon dioxide, SiO2. In the structure of solid SiO2, • each silicon atom is bonded to x oxygen atoms, • each oxygen atom is bonded to y silicon atoms, • each bond is a z type bond. What is the correct combination of x, y and z in these statements? x y z A 2 1 covalent B 2 1 ionic C 4 2 covalent D 4 2 ionic 7 In which compound does one of the atoms or ions have a different electronic configuration from each other? A carbon dioxide B phosphorus trichloride C sodium oxide D magnesium chloride 8 Which solid oxide does not lower the pH when added to sodium hydroxide solution? A aluminium oxide B silicon dioxide C phosphorus oxide D lithium oxide ���

5 No part of the paper is to be reproduced without the approval of the Principal of Temasek Secondary School. 9 The results of some experiments with sulfur dioxide are shown. experiment description result 1 mix with dilute hydrochloric acid does not react 2 mix with sodium hydroxide a salt forms 3 add Universal Indicator Universal Indicator turns purple 4 add acidified aqueous potassium manganate(VII) purple solution turns colourless Which results are correct? A 1, 2 and 4 B 2, 3 and 4 C 1 and 2 only D 3 and 4 only 10 The table shows the concentration and pH values of the aqueous solutions L and M. L M concentration in mol/dm3 2 2 pH 6 9 Student P concluded that L is a strong acid. Student Q concluded that the extent of ionisation is low in L and high in M. Which student(s) is(are) correct? A both P and Q B neither P nor Q C P only D Q only ���

6 No part of the paper is to be reproduced without the approval of the Principal of Temasek Secondary School. 11 A student investigates two acids W and X. The same volumes of W and X are reacted separately with excess magnesium. The student makes the following observations. 1 Hydrogen gas is produced at a faster rate with W than with X. 2 The total volume of hydrogen gas produced is the same for both acids. Which statement explains these observations? A The pH of W is higher than the pH of X. B W is an organic acid. C W is more concentrated than X. D W is a strong acid while X is a weak acid. 12 Which reaction does not involve neutralisation? A H2SO4(aq) + 2NH3(aq) → (NH4)2SO4(aq) B H2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2HCl(aq) C H2SO4(aq) + CuO(s) → CuSO4(aq) + H2O(l) D H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O(l) 13 Zinc reacts with hydrochloric acid according to the following equation. Zn + 2HCl → ZnCl2 + H2 The following statements were made about the reaction. 1 A 3.25 g sample of zinc reacts with an excess of hydrochloric acid to give 0.050 mol of zinc chloride. 2 A 6.50 g sample of zinc reacts completely with exactly 100 cm 3 of 1.00 mol/dm3 hydrochloric acid. 3 A 13.0 g sample of zinc reacts with an excess of hydrochloric acid to give 9.60 dm3 of hydrogen at room temperature and pressure. Which statements are correct? A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 ���

7 No part of the paper is to be reproduced without the approval of the Principal of Temasek Secondary School. 14 The table shows appropriate indicators used to identify the endpoint in titrations. indicator acidic colour range of colour change alkaline colour methyl orange red 3.1 – 4.4 yellow methyl red red 4.4 – 6.2 yellow bromothymol blue yellow 6.0 – 7.6 blue cresolphthalein colourless 8.1 – 9.7 red alizarin yellow yellow 10.1 – 12.0 red Curve 1 shows the changes in pH when NaOH was titrated to HCl in a conical flask. Curve 2 shows the changes in pH when NaOH was titrated to a different acid in another conical flask. The appropriate indicator for titration to obtain curve 1 is bromothymol blue. Using the table, what is the appropriate indicator for curve 2? A bromothymol blue B cresolphthalein C methyl orange D methyl red 15 Which statement about ammonia is correct? A Ammonia gas turns moist blue litmus paper red. B Ammonia is used to increase pH of acidic soil. C Ammonia is produced when a nitrate solution is warmed with sodium hydroxide. D Ammonia molecule contains two pairs of electrons not involved in bonding. 0 10 20 30 40 volume of NaOH added / cm3 curve 2 14 7 0 pH 0 10 20 30 40 volume of NaOH added / cm3 curve 1 14 7 0 pH ���

8 No part of the paper is to be reproduced without the approval of the Principal of Temasek Secondary School. 16 One mole of compound X gives three moles of ions in aqueous solution. X reacts with ammonium carbonate to give an acidic gas. What is compound X? A calcium hydroxide B ethanoic acid C sodium hydroxide D sulfuric acid 17 A sample of solid magnesium hydroxide is made by adding an excess of aqueous sodium hydroxide to an aqueous solution containing 1.20 g magnesium sulfate. The mass of magnesium hydroxide formed is 0.26 g. Wha