2022 TPSS Chem Prelims P1

This document consists of 17 printed pages. © TPSS/6092/2022/SEC4E/PE TAMPINES SECONDARY SCHOOL Secondary Four Express PRELIMINARY EXAMINATIONS 2022 NAME CLASS REGISTER NUMBER CHEMISTRY 6092 / 01 Paper 1 14 Sep 2022 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your class, index number and name 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 Multiple Choice Answer Sheet. INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. Use of calculator is allowed. Each correct answer will score one mark. No marks will be deducted for a wrong answer. A copy of the Periodic Table is printed on page 17. The use of an approved scientific calculator is expected, where appropriate. For Examiner’s Use Paper 1 (40 marks) [Turn over O ���

2 1 A student put exactly 25.0 cm3 of dilute hydrochloric acid into a conical flask. The student added 2.5 g of solid sodium carbonate and measured the change in temperature of the mixture. Which apparatus does the student need to use? A balance, measuring cylinder, thermometer B balance, pipette, stopwatch C balance, pipette, thermometer D burette, pipette, thermometer 2 The diagram below shows a set-up to prepare a dry sample of ammonia gas. The experiment failed. What modifications should be done to correct the set-up? 1 An alkali should be placed in the test-tube instead of an acid. 2 Anhydrous calcium oxide should be used instead of concentrated sulfuric acid. 3 The gas should be collected in a gas syringe instead of by displacement of water. A 1 only B 3 only C 1 and 2 only D 1, 2 and 3 ���

3 3 Which statement best explains why two liquids can be separated by fractional distillation? A Both have different boiling points. B Both have different densities. C Both have different masses. D Both have different reactivities. 4 A student carried out a chromatography of a sample to separate amino acids present. He performed a second chromatography experiment on the sample. The following shows the two chromatograms obtained. Why do the two chromatograms show different results? A The solvent moved up the paper at different speeds. B Different solvents were used for the two experiments. C The sample for the second experiment was contaminated. D The sample for the second experiment was more concentrated. 5 Which of the following steps can be used to separate sodium sulfate from calcium sulfate? A dissolving in water → filtration → distillation of filtrate B dissolving in water → filtration → evaporation of filtrate C dissolving in water → distillation → evaporation of filtrate D sublimation → dissolving in water → evaporation of filtrate ���

4 6 Four gas jars each contain one of the gases ammonia, chlorine, hydrogen chloride and oxygen. A strip of damp blue litmus paper and a strip of damp red litmus paper are placed in each jar. In which gas jar will both the damp blue litmus paper and the damp red litmus paper change colour? 7 An alloy consists of two elements. On addition of concentrated nitric acid, it dissolves completely. When aqueous sodium hydroxide is added, a blueish-white precipitate is formed. The precipitate turns more bluish when excess sodium hydroxide is added. Which two elements form the alloy? A copper and ammonium B copper and calcium C copper and iron D copper and zinc ���

5 8 Which reagent can be used to differentiate ammonium sulfate from ammonium carbonate? A aluminium foil and sodium hydroxide solution B aqueous sodium hydroxide C aqueous barium nitrate D hydrochloric acid 9 The melting and boiling points of four substances are given in the table below. substance melting point / °C boiling point / °C P Q R S 104 –18 20 545 128 24 212 1713 Based on the data given, which substance is a solid at room temperature and is likely to form a gas upon heating? A P B Q C R D S 10 An ion, X2–, has 18 neutrons and 18 electrons. What does its nucleus contain? A 16 protons and 16 neutrons B 16 protons and 18 neutrons C 18 protons and 16 protons D 18 protons and 18 neutrons ���

6 11 Iron has four stable isotopes and the percentage abundance of each isotope is shown below. isotope percentage abundance / % 54Fe 5.8 56Fe 91.6 57Fe 2.2 58Fe 0.4 What is the relative atomic mass of iron? A 55.7 B 55.9 C 56.0 D 56.2 12 Five substances are shown below. Zn (s) NaCl (s) H2SO4 (aq) MgCl2 (l) graphite How many of the substances contain delocalised electrons? A 0 B 1 C 2 D 3 13 An organic compound is shown below. How many electrons are involved in chemical bonding in the compound? A 13 B 14 C 26 D 28 ���

7 14 The physical properties of three substances are shown in the table below. substance melting point / °C boiling point / °C electrical conductivity solid liquid aqueous X –114 –85 poor poor good Y 3550 3825 good good insoluble Z 402 953 poor good insoluble Which of the following correctly identifies X, Y and Z? X Y Z A nitrogen dioxide potassium iodide silicon dioxide B sodium chloride silicon chloride zinc C hydrogen chloride graphite lead(II) iodide D sodium diamond calcium sulfate 15 Which of the following has the same number of molecules as 60 cm3 of carbon dioxide at room temperature and pressure? A 0.0850 g of ammonia B 25 cm3 of 0.10 mol/dm3 aqueous hydrochloric acid C 60 cm3 of ethanol liquid D 3.0 × 1021 atoms of oxygen 16 Ferrite is a mineral that is made of a mixture of the oxides of calcium and iron. It contains 18.5% calcium and 51.9% iron by mass. What is the empirical formula of ferrite? A CaFe2O B CaFe2O4 C Ca2FeO2 D Ca4Fe2O ���

8 18 An electrolytic cell is shown below. Which beakers show a change in the colour of the electrolyte? A beakers X and Y B beakers Y and Z C beakers X and Z D beakers X, Y and Z 17 Aqueous titanium(III) chloride reacts violently with water to produce a titanium(IV) oxide precipitate, hydrochloric acid and hydrogen gas. Which of the following shows the correct ionic equation for the reaction? A 2TiCl3 (aq) + 4H2O (l) → 2TiO2 (s) + 6HCl (aq) + H2 (g) B 2Ti3+ (aq) + 4H2O (l) → 2TiO2 (s) + 6H+ (aq) + H2 (g) C Ti3+ (aq) + 3Cl– (aq) → Ti4+ (aq) + 3Cl– (aq) D Ti3+ (aq) + 3Cl– (aq) + 2H+ (aq) → Ti4+ (aq) + 3Cl– (aq) + H2 (g) ���

9 19 The purification of copper is shown below. The impure copper anode had an initial mass of 100 g while the pure copper cathode had an initial mass of 10 g. At the end of the purification, the anode weighed 10 g while the cathode weighed 80 g. What is the percentage impurity of the copper anode? A 10% B 20% C 30% D 90% 20 Which process is exothermic? A Melting of ice B Evaporation of ethanol C Formation of iodine vapour from iodine crystals D Condensation of water vapour to form liquid droplets pure copper cathode impure copper anode ���

10 21 The diagram below shows the energy profile for a reaction. Which statements about this reaction are correct? 1 More energy is needed to break the bonds than is released when new bonds are formed. 2 Route 1 and route 2 give the same overall equation for the reaction. 3 Route 2 uses a catalyst. 4 The reaction is exothermic. A 1, 2 and 3 B 1 and 2 only C 2, 3 and 4 D 3 and 4 only