Punggol Prelim P1

EXP PUNGGOL SECONDARY SCHOOL SECONDARY 4 EXPRESS 2024 PRELIMINARY EXAMINATION QUESTION & ANSWER BOOKLET NAME CLASS INDEX NUMBER Chemistry Paper 1 6092 27 August 2024 Additional materials: MCQ answer Sheet 1 hour READ THESE INSTRUCTIONS FIRST Write your class, register number and name on all the work you hand in. Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. 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 18. The use of an approved scientific calculator is expected, where appropriate. For Examiner’s use Parent’s Signature - - - - - - Total /40 This paper consists of 18 printed pages and 0 blank page.

2 1 The diagram shows the apparatus used to obtain pure water from tap water and concentrated salt solution. What are the possible temperatures indicated at X, Y and Z? X Y Z A 100 °C 100 °C 100 °C B 100 °C 100 °C 105 °C C 95 °C 100 °C 105 °C D 105 °C 95 °C 100 °C

3 2 The diagram shows a beaker full of gas X inverted over a porous pot containing gas Y. A known liquid is used in the container. None of the gases provided below are soluble in the liquid. Which pair of gases will lead to the liquid spilling out at the outlet O? Gas X Gas Y A chlorine helium B argon hydrogen C flourine helium D neon chlorine 3 Products made of plastics have greatly improved our daily lives. Plastics can be made from fractions derived from crude oil. 1 Plastics are mixtures of substances with different boiling points. 2 Crude oil is a mixture of substances with different boiling points. 3 The chemical composition of the recycled plastics remains unchanged using the chemical method of recycling plastics. 4 Plastics such as poly(ethene) is an example of addition polymer. Which statements about plastics and crude oil are correct? A 2, 3 and 4 only B 1, 3 and 4 only C 2 and 4 only D 1 and 3 only

4 4 Salicylic acid is a substance used in skin ointments and a sample of it is found to contain impurities like iron and sodium iodide. Salicylic acid sublimes at 76 oC and is soluble in water. What is the best method to obtain pure salicylic acid from the sample? A Add water, filter and evaporate B Add water, filter and sublime C Use magnets, add water and filter D Add water, filter, crystallise and sublime 5 An ion R2− contains 45 neutrons and 36 electrons. Which of the following shows the proton number and nucleon number of an atom of R? proton number nucleon number A 34 79 B 36 81 C 34 81 D 38 83 6 The element thallium, Tl, has only two isotopes with mass numbers 203 and 205. The relative abundance of Tl -203 is 30%. Which of the following is the relative atomic mass of thallium? A 203.8 B 204.0 C 204.4 D 204.8 7 The boiling points of aluminium chloride and carbon tetrachloride are shown below. boiling point / oC aluminium chloride 180 carbon tetrachloride 76 Aluminium chloride does not conduct electricity in both solid and molten states. Which of the following best explain the difference in boiling points between the two compounds? A Electrostatic forces of attraction between the oppositively charged ions in aluminium chloride are stronger. B Metallic bonds in aluminium chloride are stronger. C Covalent bonds in aluminium chloride are stronger. D Intermolecular forces of attraction in aluminium chloride are stronger.

5 8 Ionic bonding results when electrons are transferred from one atom to another. How many electrons are transferred from/to each of the atoms of elements magnesium, zinc, nitrogen, and fluorine when they form ionic compounds? magnesium zinc nitrogen fluorine A 2 2 3 1 B 2 1 3 7 C 2 2 5 1 D 1 1 5 7 9 The structure of phosphoric acid is shown below. What is the total number of shared electrons in one molecule of phosphoric acid? A 7 B 8 C 14 D 16 10 Patients with iron deficiency are prescribed with iron tablets. When the iron in these tablets reacts with oxygen, it forms iron(II) oxide. A sample of 100 g of iron tablets yields 36 g of iron(II) oxide. What is the percentage by mass of iron in the tablet? A 14% B 28% C 42% D 56% 11 A sample of sodium was heated in excess oxygen according to the equation shown below. 4Na (s) + O 2 (g)  2Na2O (s) The percentage purity of the sodium sample was 80%. What would be the maximum mass of sodium oxide obtained when 2.56 g of the impure sodium was used? A 0.96 g B 1.38 g C 2.76 g D 3.45 g

6 12 15.7 g of a metal chloride, XCl4, was heated with zinc. 7.17 g of metal X was obtained. XCl4 + 2Zn → X + 2ZnCl2 What could be the identity of X? A Coଶ଻ହଽ B Zrସ଴ଽଵ C Inସଽଵଵହ D Snହ଴ଵଵଽ 13 A solution of a strong acid, HX, contains molecules of water and the ions H+ and X−. Which statement is correct? A The pH value of the acid solution is above 7. B The acid solution contains OH- ions. C The acid solution contains more H+ ions than X− ions. D The acid solution contains higher concentration of HX molecules than H+ ions. 14 What is the substance that farmers add to reduce acidity in soils? A calcium hydroxide B magnesium oxide C sodium hydroxide D aqueous ammonia

7 15 10.00 cm3 solutions of 0.10 mol/ dm3 concentration of sulfuric acid, hydrochloric acid and ethanoic acid were separately titrated with a 0.10 mol/ dm3 solution of sodium hydroxide until neutralisation is complete. 1 Ethanoic acid and hydrochloric acid would require the same volume of sodium hydroxide solution. 2 Hydrochloric acid would require more sodium hydroxide solution than ethanoic acid. 3 Hydrochloric acid would require more sodium hydroxide than sulfuric acid. 4 Hydrochloric acid would require lesser sodium hydroxide than sulfuric acid. Which statements are correct? A 1 and 4 only B 2 and 4 only C 1 and 3 only D 2 and 3 only 16 A student wants to prepare calcium sulfate which is an insoluble salt. Which pair of reagents are the most suitable for making calcium sulfate? A calcium and sulfuric acid B calcium carbonate and sulfuric acid C calcium nitrate and sulfuric acid D calcium oxide and sulfuric acid 17 A salt, T, on warming with excess aqueous sodium hydroxide, produced a gas that turned damp red litmus paper blue. No further gas was produced when a piece of aluminium foil was added and warmed. A white precipitate was produced when barium nitrate solution was added to solution T. What could be T? A ammonium nitrate B ammonium sulfate C aluminium nitrate D aluminium sulfate

8 18 In which of the following reactions is the underlined substance acting as the reducing agent? A Br2 + 2I- → I2 + 2Br− B 3CuO + 2NH3 → N2 + 3H2O + 3Cu C CaCO3 + 2H+ → Ca2+ + CO2 + H2O D Mg + Pb2+ → Mg2+ + Pb 19 Which statement about the electrolysis of molten potassium chloride is correct? A A gas that bleaches damp litmus paper is produced at the anode. B No gas is produced at the anode. C