2023 YTSS Chem Prelims P1

NAME: ( ) CLASS: YISHUN TOWN SECONDARY SCHOOL PRELIMINARY EXAMINATION 2023 SEC 4 EXPRESS CHEMISTRY (6092/1) DATE : 30 Aug 2023 DAY : Wednesday DURATION: 1 hr MARKS: 40 marks ADDITIONAL MATERIALS Multiple Choice Answer Sheet (OMS) READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces provided at the top of this page. There are forty questions. 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. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. INFORMATION FOR CANDIDATES Any rough working should be done in this booklet. You may use an approved calculator. A copy of the Periodic Table is printed on the last page. This question paper consists of 16 printed pages 1 A student wanted to collect a dry sample of gas X using the reactants and apparatus below.

2 What is gas X and a suitable drying agent that can be used? Gas X Drying agent A hydrogen chloride calcium oxide B ammonia concentrated sulfuric acid C hydrogen chloride concentrated sulfuric acid D ammonia calcium oxide 2 Three balloons are placed inside plastic containers containing different gases at room temperature and pressure as shown below. I II III Which correctly describes the balloon in each set up after a while? I II III A becomes bigger remains the same deflates B becomes bigger becomes bigger becomes bigger C deflates remains the same becomes bigger D deflates becomes bigger becomes bigger carbon dioxide nitrogen helium hydrogencarbon monoxide neon

3 3 The atmosphere of Venus contains mainly oxygen, argon and nitrogen. The melting and boiling points of these gases are shown in the table below. What temperature should the sample of air be decreased to in order to obtain only liquid oxygen? A -180oC B -185oC C -187oC D -198oC 4 The apparatus shown is used to distil butanoic acid (boiling point 164ºC) from a mixture of butanoic acid and water. Which graph best shows the change in the concentration of the butanoic acid in flask F during the distillation process? gas melting point / oC boiling point / oC oxygen -219 -183 argon -189 -186 nitrogen -210 -196 A B C D

4 5 Which solution when added to both the reagents below will produce a gas? • Sodium carbonate • Aqueous sodium hydroxide with aluminium foil A dilute nitric acid B aqueous ammonium nitrate C dilute sulfuric acid D aqueous potassium sulfate 6 Ions of two isotopes of nickel are shown below. They are labelled as X and Y. X Y Which statement is correct about these ions? A Both ions have the same number of electrons but different number of neutrons. B In both ions, there are more electrons than protons. C Ion X has the same mass as ion Y. D Each ion has more protons than neutrons in its nucleus. 7 An alloy of iron and carbon was added to a beaker of dilute nitric acid as shown in the diagram below. Which row correctly shows the type of particles present in the substances as shown in the diagram? iron carbon dilute nitric acid gas product A ions and electrons atoms ions and molecules molecules B ions molecules ions molecules C ions molecules ions and molecules atoms D ions and electrons atoms ions atoms

5 8 The outer electronic structure of a molecule is shown below. What could elements X and Y be? X Y A magnesium oxygen B carbon oxygen C lead oxygen D silicon chlorine 9 A substance has the following structure. Which of the following statements about this structure are correct? I Particle X may be a silicon atom. II This is a simple molecular compound with strong covalent bonds between atoms. III This substance is soluble in organic solvents. IV This substance is stable to heat. A I and II only B I and IV only C II and III only D II and IV only

6 10 The diagram shows the structure of ethanoyl chloride. What is the total number of valence electrons not used for bonding? A 5 B 10 C 14 D 26 11 Gaseous chlorine was passed through the following apparatus. The apparatus was continuously heated. What observations would be made at regions 1, 2 and 3? Region 1 Region 2 Region 3 A reddish brown gas black solid violet gas B reddish brown gas violet gas black solid C yellow gas reddish brown gas violet gas D yellow gas reddish brown gas black solid chlorine gas potassium bromide potassium iodide solid gel cotton wool to pump

7 12 P is a Group I element. What would happen when a small piece of P is put into a bowl that contains water and a few drops of litmus solution? I Heat is released. II An electrolyte is formed. III The solution turns blue. IV A gas is given off. A I and III only B III and IV only C I, III and IV only D I, II, III and IV 13 In an experiment, 1 cm3 of a gaseous hydrocarbon, Z, requires 4 cm3 of oxygen for complete combustion to give 3 cm3 of carbon dioxide. All gas volumes are measured at r.t.p. Which formula represents Z? A C2H2 B C2H4 C C3H4 D C3H8 14 68 g of impure hydrogen peroxide decomposes in the presence of manganese (IV) oxide to give 1.2 dm3 of oxygen gas as follows. 2H2O2 → O2 + 2H2O What is the percentage purity of the hydrogen peroxide? A 2.5% B 5.0% C 10.0% D 15.0% 15 A chloride of iron contains 55.9% of chlorine by mass. What is the empirical formula of this chloride? A Fe2Cl6 B FeCl C FeCl2 D FeCl3

8 16 The graph shows how the pH changes in a reaction between an acid and an alkali. What conclusions can be deduced from the graph? 1 An acid is added to a fixed volume of an alkali. 2 Only salt and water are present at part Z of the graph. 3 Neutralisation occurs at about pH 7. 4 A weak acid was added to a strong alkali. A 1 and 2 only B 1 and 3 only C 2 and 4 only D 1, 2 and 3 17 Which graph shows the solution formed when one mole of a weak acid, HX is dissolved in 1 dm3 of water? A B C D Z volume of solution added / cm3

9 18 The structure below is citric acid. How many moles of sodium hydroxide are needed to neutralise one mole of citric acid? A 1 B 2 C 3 D 4 19 Which of these sequences of reaction produces the best yield of calcium sulfate? A Adding dilute nitric acid to calcium carbonate followed by dilute sulfuric acid. B Mixing solid calcium nitrate and solid potassium sulfate. C Addind calcium carbonate to dilute sulfuric acid. D Adding calcium oxide solid to dilute sulfuric acid. 20 Which statement about metals and their compounds is not correct? A Unreactive metals are likely to be found as elements in soil or rocks. B Metals low in the reactivity series are generally extracted from their oxides by heating with carbon. C Heating magnesium with iron (III) oxide produces iron and magnesium oxide. D A higher temperature is needed to reduce copper (II) oxide to copper than zinc oxide to zinc by hydrogen. 21 A metal consists of a lattice of positive ions in a ‘sea of electrons’. What happens to the electrons and positive ions in a metal wire when an electric current is passed through it? electrons positive ions A replaced by new electrons replaced by new ions B replaced by new electrons unchanged C unchanged replaced by new ions D unchanged unchanged

10 22 Steel is an alloy of iron with a very small percentage of carbon. Which statement is incorrect? A An increase in the percentag