2025 GDLSS P1

1 GREENDALE SECONDARY SCHOOL Preliminary Examination 2025 STUDENT NAME CLASS 4 TEACHING GROUP REG. NO CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet 6092/01 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class, teaching group and register number in the spaces provided above and on the Multiple Choice Answer Sheet 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 14. The use of an approved scientific calculator is expected, where appropriate This document consists of 14 printed pages. [Turn over

2 1 Five students each dissolved an indigestion tablet in 100 cm3 of water. They then titrated 25.0 cm3 of their solutions with dilute hydrochloric acid, using the same indicator. The results are shown in the table. student 1 2 3 4 5 titration value / cm3 20.4 20.5 20.4 20.6 22.0 Which statement could explain the result obtained by student 5? A The burette was washed out with hydrochloric acid. B The pipette was washed out with the tablet solution. C The student measured to the top of the meniscus in the pipette. D The titration flask was washed out with the tablet solution. 2 An excess of hydrochloric acid is added to 0.10 mol of magnesium in the apparatus shown. Why is it impossible to measure the total volume of hydrogen produced using this apparatus? A Hydrogen is less dense than air. B Hydrogen is soluble in hydrochloric acid. C There is air in the tube. D The volume of hydrogen gas formed is greater than 100 cm3. syringe 100 cm3 dilute hydrochloric acid magnesium

3 3 From which mixture can the underlined substance be obtained by adding water, stirring and filtering? A calcium carbonate and sodium chloride B copper(II) sulfate and sodium chloride C ethanoic acid and ethanol D iron and magnesium 4 The chromatogram of substance S is shown. Some distances, W, X, Y and Z, are labelled on the diagram. How is the Rf value of substance S calculated? A X Y B W Z C Y X D Y W 5 An atom of one isotope of chlorine is represented by the symbol 35Cl. Which row is correct for an atom of a different isotope of chlorine? number of protons neutrons electrons A 17 20 18 B 17 20 17 C 17 18 17 D 18 17 18 solvent front substance S baseline solvent level W X Z Y

4 6 Small crystals of purple KMnO 4 and orange K 2Cr2O7 were placed at the centre s of separate petri dishes filled with agar jelly. They were left to stand under the same physical conditions. After some time, the colour of each substance had spread out as shown. The lengths of the arrows indicate the relative distances travelled by particles of each substance. Which statement is correct? A Diffusion is faster in dish 1 because the molecular mass of the particles is greater. B Diffusion is faster in dish 2 because the molecular mass of the particles is greater. C Diffusion is slower in dish 1 because the molecular mass of the particles is smaller. D Diffusion is slower in dish 2 because the molecular mass of the particles is greater. 7 The diagram shows some properties of particles in an atom. To which labelled part of the diagram does an electron belong? dish 1 dish 2 KMnO4 K2Cr2O7

5 8 Which of the following is a property of aqueous potassium iodide? A It does not conduct electricity. B It is decolourised by chlorine. C It reacts with aqueous bromine to form iodine. D It reacts with aqueous silver nitrate to form a white precipitate. 9 A covalent molecule, M, contains four shared pairs of electrons. What is M? A ammonia B hydrogen chloride C methane D water 10 Which diagram represents a mixture of compounds? 11 Which statements about alloys are correct? 1 They are formed by a chemical reaction between two metals. 2 They are good conductors of electricity as they have mobile ions. 3 Their structures contain metal cations that are disorderly arranged. A 1 and 2 B 1 and 3 C 2 and 3 D 3 only 12 Silicon dioxide, diamond, graphite and iodine all contain covalent bonds. Which statement is correct? A Diamond has atoms that are arranged in a tetrahedral structure. B Graphite is used as lubricant due to strong covalent bonds between atoms. C Silicon dioxide and graphite both have mobile electrons and therefore can conduct electricity. D Upon gentle warming, iodine changes from solid to gas as its covalent bonds are weak.

6 13 When 7 g of iron reacts with 4 g of sulfur, 11 g of iron(II) sulfide is produced. What will be produced if 7 g of iron is reacted with 7 g of sulfur? A 11 g of iron(II) sulfide and 3 g of unreacted iron B 11 g of iron(II) sulfide and 3 g of unreacted sulfur C 11 g of iron(II) sulfide only D 14 g of iron(II) sulfide only 14 On adding 100 g of impure limestone, CaCO 3 (Mr = 100), to excess hydrochloric acid, 6.0 dm3 of CO2 was evolved at room temperature and pressure. What is the purity of the limestone? A 25% B 50% C 75% D 100% 15 248 g of phosphorus vapour has the same volume as 142 g of chlorine gas at the same temperature and pressure. What is the formula of a molecule of phosphorus? A P8 B P4 C P2 D P 16 All ammonium salts on heating with sodium hydroxide produce ammonia gas. From which ammonium salt can the greatest mass of ammonia be obtained? A 0.5 mol (NH4)3PO4 B 0.5 mol (NH4)2SO4 C 1.0 mol NH4Cl D 1.0 mol NH4NO3 17 4.0 cm3 of 1.0 mol/dm3 aqueous copper(II) sulfate was mixed with 8 cm3 of 1.0 mol/dm3 aqueous sodium carbonate in a reaction vessel. CuSO4 + Na2CO3 → Na2SO4 + CuCO3 What did the reaction vessel contain when the reaction was complete? A a colourless solution only B a green precipitate and a blue solution C a green precipitate and a colourless solution D a white precipitate and a blue solution

7 18 A titration method is used to prepare a pure soluble sulfate salt from dilute sulfuric acid. What is the other reagent? A copper (II) oxide B zinc C potassium hydroxide D iron(II) carbonate 19 Which statements about a hydrogen fuel cell are correct? 1 The main form of energy released by the fuel cell is heat. 2 The reaction is a redox reaction. 3 An acidic gas is produced. 4 Water is the only chemical product. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4 20 Element X is extracted by the electrolysis of molten compound of element X and Y. The electrode reactions are as shown. positive electrode negative electrode 2Y2– → Y2 + 4e– X2+ + 2e– → X Which of the following could be the compound? A aluminium oxide B calcium chloride C magnesium oxide D potassium chloride 21 Selenium, Se, is in the same group of the Periodic Table as sulfur. What is the formula of potassium selenide? A K2Se B KSeO4 C K2SeO4 D K2SeO3 22 Which noble gas has the highest concentration in dry air? A argon B helium C kryton D neon

8 23 Which row shows the properties of a Group 1 metal? density hardness A high hard B high soft C low hard D low soft 24 Which statements about a transition elem