2022 AMKSS Chem Prelims P1

1 Name Class Index Number ANG MO KIO SECONDARY SCHOOL PRELIMINARY EXAMINATION 2022 SECONDARY FOUR EXPRESS CHEMISTRY 6092 /01 Total Mark: 40 31 August 2022 / Wednesday Setters: Ms Tay Siew Peng 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Write your Name, Class and Index Number in the spaces on the Multiple Choice Answer Sheet. Do not use staples, paper clips, glue or correction fluid/tape. 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. Read the instructions on the Multiple Choice 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 15. The use of an approved scientific calculator is expected, where appropriate. For Examiner’s use TOTAL This document consists of 15 printed pages, including the cover page. [Turn over] �

2 1 A student has to measure 30.60 cm3 of aqueous sodium bromide solution. Which apparatus should the student select? A B C D 2 Caffeine is a white solid that melts at 235 °C. A sample of impure caffeine is found to be contaminated with sugar. Propanone is an organic solvent with a low boiling point. Caffeine and sugar have different solubilities in water and propanone. substance solubility in water solubility in propanone caffeine moderate high sugar high insoluble The following steps could be carried out to obtain pure caffeine from a mixture of caffeine and sugar. I add excess water II add excess propanone III cool and crystallise IV filter the mixture V heat the filtrate In what order should the steps be carried out? A I, IV, III and V B I, IV, V and III C II, IV, III and V D II, IV, V and III �

3 3 Distillation is used to obtain water from a copper(II) sulfate solution. Which graph shows the change in concentration of the copper(II) sulfate solution in the distillation flask? A B C D 4 A new substance was discovered and a series of experiments were conducted on it. Which observation suggests that the substance cannot be an element? A It has a fixed boiling point. B It dissolves in water to form a yellow-green solution. C When heated strongly, a brown solid and a yellow gas are produced. D When heated in air, it can form oxides with two different chemical formulae. 5 Three atoms are shown. 32 16 X 33 16 Y 32 17 Z What can be deduced from the proton numbers and nucleon numbers of X, Y and Z? A X and Y are the same element. B X and Z are the same element. C Y has more protons than X. D Z has more neutrons than Y. 6 At what temperature does a dilute sodium chloride solution begin to boil? A 98 oC B 100 oC C 103 oC D 801 oC �

4 7 The diagram shown is set up using different gases in two beakers P and Q. The inverted smaller beakers both contain oxygen gas. Which gases, when placed in beakers P and Q respectively, will cause the water level at R to rise initially? P Q A ammonia nitrogen B argon oxygen C carbon dioxide nitrogen D oxygen carbon dioxide 8 The diagrams show the structures of two solids, P and Q. P Q Which row is correct? has covalent bonding conducts electricity A P only P only B P only Q only C both P and Q P only D both P and Q Q only Q P R �

5 9 Zinc and zinc chloride are both conductors of electricity in their molten states. What particles cause the two substances to conduct electricity in molten state? zinc zinc chloride A mobile electrons only mobile electrons only B mobile electrons only mobile ions only C mobile electrons and ions mobile ions only D mobile electrons and ions mobile electrons and ions 10 A beam of electron (e), neutron (n) and proton (p) is passed across a positively charged plate. Which diagram correctly shows how the particles are affected by the plate? A B C D 11 Element M has n protons and can form M2+ ions. Element N has (n + 3) protons. Which of the following correctly describes the type of compound and the chemical formula of compound formed between M and N? type of compound chemical formula A covalent compound MN2 B covalent compound M3N2 C ionic compound MN2 D ionic compound M3N2 12 The empirical formula of compound X is CH2 and the relative molecular mass, Mr of X, is 70. What is the molecular formula of X? A CH2 B C2H4 C C5H10 D CnH2n �

6 13 Which compound contains both ionic bonds and covalent bonds? A Al2O3 B NaCl C SiO2 D ZnSO4 14 A chemist wants to make calcium nitrate. He starts with 8.00 g of pure calcium oxide and an excess of dilute nitric acid. He produces 12.65 g of pure anhydrous calcium nitrate. What is the percentage yield of calcium nitrate? [relative atomic masses, Ar: Ca, 40; N, 14; H, 1; O, 16] A 54.0% B 63.2% C 67.1% D 86.8% 15 Chlorine can be prepared from concentrated hydrochloric acid and potassium manganate(VII). The reaction is represented as: 2KMnO4 + x HCl → 2KCl + 2MnCl2 + y H2O + z Cl2 What are the values of x, y and z? x y z A 16 8 5 B 5 8 16 C 8 5 16 D 16 5 8 16 Sulfur dioxide can react with oxygen to form sulfur trioxide as shown. 2SO2 (g) + O2 (g)  2SO3 (g) If 200 cm 3 of sulfur dioxide is reacted with 200 cm 3 of oxygen, what is the volume of gases remaining after the reaction? A 100 cm3 B 200 cm3 C 300 cm3 D 400 cm3 �

7 17 In an acid-base titration, a 0.10 mol/dm3 alkali is added to 10 cm3 of 0.10 mol/dm3 dilute acid. The graph below shows the change in pH during the titration. Which of the following represents the titration shown in the graph? A ethanoic acid and aqueous sodium hydroxide B ethanoic acid and aqueous ammonia C nitric acid and aqueous sodium hydroxide D nitric acid and aqueous ammonia 18 The table gives information about three indicators. indicator colour at pH 1 pH at which indicator changes colour colour at pH 12 thymol blue red 3 yellow congo red blue 5 red phenolphthalein colourless 10 red What colour would be obtained when each indicator is added separately to pure water? thymol blue congo red phenolphthalein A red blue red B yellow blue colourless C yellow blue red D yellow red colourless �

8 19 Which substance has the greatest number of atoms? A 33 g of CO2 B 2 g of He C D 27 g of F2 40 g of MgO 20 In which of the following reactions is dilute hydrochloric acid not behaving as an acid? A NH3 + HCl → NH4Cl B AgNO3 + HCl → AgCl + HNO3 C CuCO3 + 2HCl → CuCl2 + CO2 + H2O D Mg + 2HCl → MgCl2 + H2 21 The labels fell off two bottles each containing a colourless solution, one of which was sodium carbonate solution and the other was sodium chloride solution. Which of the following tests would allow the identification of the solutions? A addition of dilute nitric acid B addition of aqueous ammonia C addition of sodium hydroxide solution D addition of lead(II) nitrate solution 22 Which of the following reactants could be used to prepare a pure sample of sodium sulfate safely? A sodium carbonate and sulfuric acid B sodium and sulf