KSS Prelim Paper 1 Chemistry 2026

1 Candidate Name: ( ) Class: READ THESE INSTRUCTIONS FIRST Write your name, register number and class in the spaces provided. There are forty questions in this paper. Answer all questions. For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct and record your choice in soft pencil on the separate Answer Sheet. 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 The use of an approved scientific calculator is expected, where appropriate. The total number of marks for this paper is 40. ____________________________________________________________________________________________________________ This Question Paper consists of 18 printed pages. KRANJI SECONDARY SCHOOL Preliminary Examinations Secondary 4 Express / 5 Normal (Academic) CHEMISTRY Paper 1 Multiple Choice 6092/01 Tuesday 1 September 2026 1 hour KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY 4E/5N

2 1 A titration is completed. 25.0cm3 of aqueous sodium hydroxide is added to a conical flask. A few drops of methyl orange indicator are added. Dilute hydrochloric acid is added slowly to the mixture until the colour changes. Which row is correct? apparatus used to add alkali apparatus used to add acid colour change of indicator A measuring cylinder burette red to orange B pipette burette red to orange C pipette burette yellow to orange D pipette measuring cylinder yellow to orange 2 The diagram shows the setup of a chemical reaction that produces a gas. The gas is then dried and collected. What could the gas be? A carbon dioxide B hydrogen C oxygen D sulfur dioxide

3 3 An impure sample of compound X has a melting point of around 120oC. X is purified and its melting point is measured again. Which row is correct? method of purification melting point of pure X /oC A crystallisation 115 B crystallisation 125 C distillation 115 D distillation 125 4 Three separate processes are listed 1 obtaining ethanol from an alcoholic drink 2 obtaining iodine from a mixture of iodine and sand 3 obtaining solid sodium chloride from sodium chloride solution Which separate techniques would be used for these processes? 1 2 3 A fractional distillation crystallisation simple distillation B fractional distillation sublimation evaporation C simple distillation crystallisation filtration D simple distillation sublimation evaporation 5 When a substance changes state at constant temperature and pressure • energy is released as stronger forces of attraction form between its particles • the average distance between the particles changes very little Which changes of state is being described? A gas to liquid B liquid to gas C liquid to solid D solid to liquid

4 6 Which gas diffuses most slowly? A carbon dioxide molecule at 25oC B carbon dioxide molecules at 80oC C ethane molecules at 25oC D ethane molecules at 80oC 7 An ion X2- has m nucleons and 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) 8 The diagram shows the outer shell electrons of the atoms of two elements, Q and R. The sulfate of Q is insoluble Element R is a gas at room temperature and pressure. Which row could be correct? proton number of Q relative atomic mass of R A 12 35.5 B 12 80 C 56 35.5 D 56 80 9 Which compound contains covalent bonds? A calcium iodide B iron (II) sulfate C magnesium hydroxide D potassium phosphide

5 10 The diagram below shows the full structural formula of a molecule of sulfuric acid. Considering all the electrons, which description best describes the arrangement of electrons in a molecule of sulfuric acid? total number of electrons involved in bonding total number of electrons not involved in bonding A 6 16 B 8 24 C 16 16 D 16 34 11 Silicon dioxide has a giant covalent structure. Each silicon atom is joined to four oxygen atoms by covalent bonds. Part of the structure is shown. Which property would silicon dioxide be expect to have? A a good conductor of electricity B a high melting point C reacts with dilute hydrochloric acid D soluble in water

6 12 The structure of substance R is shown. Which row correctly identifies substance R and particles P and Q? substance R particles P particles Q A copper electron anion B graphite electron atom C lithium electron cation D sodium chloride anion cation 13 The formula of a chloride of element X is XCl4. 103g of XCl4 contains 32g of X. How many moles of X atoms does 103 grams of XCl4 contain? A 71 35.5 × 1 4 B 71 35.5 × 4 C 103 35.5 × 4 D 103 35.5 × 1 4

7 14 On heating, the nitrate of element X decomposes. 2X(NO3)2 (s) → 2XO (s) + 4NO2 (g) + O2 (g) 18.9g of X(NO 3)2 is heated and 4.8dm 3 of nitrogen dioxide, measured at room temperature and pressure, is produced. What is the relative atomic mass, Ar, of X? A 47 B 65 C 124 D 127 15 Excess iodine ions react with 15cm3 of a solution containing copper(II) ions to produce two products as shown in the following equation: 4I- + 2Cu2+ → I2 + 2CuI The resulting iodine formed from the above reaction requires 20cm 3 of 0.10 mol/dm3 of sodium thiosulfate solution during titration. The equation for the reaction is shown below: I2 + 2Na2S2O3 → 2NaI + Na2S4O6 What is the concentration of copper(II) ions in the solution? A 0.100 mol/dm3 B 0.133 mol/dm3 C 0.267 mol/dm3 D 0.304 mol/dm3 16 Brass is a mixture of copper and zinc. A sample of brass has a mass of 24.0g. When reacted with excess dilute sulfuric acid, 1.85dm3 of hydrogen gas was collected. What is the percentage of copper in the sample of brass? A 20.9% B 41.8% C 58.2% D 79.1%

8 17 Samples of dilute hydrochloric acid and dilute nitric acid were tested using Universal Indicator. The sample of dilute hydrochloric acid has a pH of 4, while the sample of the dilute nitric acid has a pH of 2. Which statement is correct? A Hydrochloric acid is a weak acid while nitric acid is a strong acid B Hydrochloric acid has a higher relative molecular mass than nitric acid C The dilute hydrochloric acid sample has ionised more than the dilute nitric acid sample D The dilute hydrochloric acid sample is less concentrated than the dilute nitric acid sample 18 Which of the following salts can be prepared by the same method? 1 calcium carbonate 2 magnesium nitrate 3 potassium chloride 4 zinc sulfate A 1 and 2 B 1 and 3 C 2 and 3 D 2 and 4 19 A salt has the chemical formula (NH4)2Fe(SO4)2. Excess aqueous sodium hydroxide was added to a solution and the mixture was heated. The mixture was left to stand. Which of the following observations would not be made? A A green precipitate was formed. B A pungent gas that turns damp red litmus blue C The precipitate dissolves in excess aqueous sodium hydroxide D The precipitate turned red-brown on standing 20 In an experiment conducted in school, Eren added 1.5g of copper(II) carbonate to 10.0cm3 of 1.0 mol/dm3 aqueous sulfuri