AES Prelim P2

Name: ………………………………( ) This Question Paper consists of 25 printed pages including this page. [Turn over ASSUMPTION ENGLISH SCHOOL PRELIMINARY EXAMINATION 2024 CHEMISTRY 6092 / 02 ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL ASSUMPTION ENGLISH SCHOOL LEVEL: Sec 4 Express DATE: 21 August 2024 CLASS: Sec 4/1 DURATION: 1 hour 45 minutes Additional Materials Provided: -NIL- INSTRUCTIONS TO CANDIDATES Do not open this booklet until you are told to do so. Write your NAME and INDEX NUMBER at the top of this page. This paper consists of 2 sections. SECTION A STRUCTURED QUESTIONS (70 marks) Answer ALL questions. Write your answers in the spaces provided. SECTION B FREE RESPONSE QUESTIONS (10 marks) Answer one question. Write your answers in the spaces provided. The number of marks is given in brackets [ ] at the end of each question or part question. The use of an approved scientific calculator is expected where appropriate. A copy of the Periodic Table is provided on Page 25. For Examiner’s use: Paper 1 / 40 Paper 2 Section A / 70 Paper 2 Section B / 10 Paper 3 / 40 Total / 160 Total (%) / 100

2 6092/02/4E/PRELIM/2024 SECTION A: STRUCTURED QUESTIONS [70 marks] Answer all questions in the spaces provided. 1 A list of substances is shown below. potassium iodide silicon dioxide copper(II) oxide iron(III) chloride graphite lead( II) oxide zinc bromide aluminium Choose from the list of substances to answer the questions below. Each substance can be used once, more than once, or not at all. (a) Which compound has a giant covalent structure? ……………………………………………………………………………………. [1] (b) Which substance reacts with both acids and alkalis? ……………………………………………………………………………………. [1] (c) Which ionic compound has a formula of XY2? ……………………………………………………………………………………. [1] (d) Which substance forms a yellow precipitate when added with aqueous silver nitrate? ……………………………………………………………………………………. [1] (e) Which substance turns from black to red brown when heated with hydrogen gas? ……………………………………………………………………………………. [1] [Total: 5]

3 6092/02/4E/PRELIM/2024 [Turn over 2 Aqueous hydrogen peroxide, H2O2, is commonly used in the sterilisation of contact lenses due to its effective antimicrobial properties. It decomposes at room temperature to form water and oxygen. (a) Write a balanced chemical equation for the decomposition of hydrogen peroxide. ……………………………………………………………………………………. [1] (b) Draw a ‘dot-and-cross’ diagram for hydrogen peroxide, H2O2. Show outer electrons only. [2] (c) Aqueous hydrogen peroxide decomposes faster when it is warmed and kept at a temperature of 50°C. Use ideas about collisions between particles to explain why. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [2] (d) A disproportionation reaction is one in which an element is both oxidised and reduced in the same reaction. Using ideas about oxidation states, state and explain if the decomposition of hydrogen peroxide is a disproportionation reaction. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [2] [Total: 7]

4 6092/02/4E/PRELIM/2024 3 Group 1 of the periodic table consists of the alkali metals. Table 3.1 shows some information about the atomic radii and ionic radii of the first four metals in Group 1. Table 3.1 element atomic radius / pm ionic radius / pm lithium (Li) 152 68 sodium (Na) 185 98 potassium (K) 227 133 rubidium (Rb) 244 148 [1 pm = 10-12 m] (a) State one physical property unique to Group 1 metals. ……………………………………………………………………………………. [1] (b) Using the data provided in Table 3.1, explain why the reactivity of Group 1 metals increases going down the group. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [2] (c) Suggest a reason for the difference in radius of a lithium atom when it forms a lithium ion. ……………………………………………………………………………………. ……………………………………………………………………………………. [1] (d) A piece of sodium metal was dropped in a trough of water and the following observations were noted. element observations sodium (Na) Reacts very quickly with water. It skids around the surface of the water and a yellow flame is seen.

5 6092/02/4E/PRELIM/2024 [Turn over (i) Suggest a reason for the underlined observation. ……………………………………………………………………………… ……………………………………………………………………………… [1] (ii) Describe how the observations will differ when a piece of potassium is dropped in the same trough of water. Explain your answer. ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… [2] [Total: 7] 4 The electrolysis of aqueous copper(II) sulfate using copper electrodes is shown in the set-up below. The table shows some information about the conduct of the experiment. current used/ A time taken/ s mass of cathode before starting / g after electrolysis / g 4.0 360 1.24 1.52 (a) Describe two differences in electrical conductivity between copper and copper(II) sulfate. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [2] aqueous copper(II) sulfate copper cathode copper anode

6 6092/02/4E/PRELIM/2024 (b) (i) Explain, with the aid of a half equation, why the mass of the cathode increased. …………………………………………………………………………….. …………………………………………………………………………….. …………………………………………………………………………….. [2] (ii) The anode had a mass of 1.20 g at the start. Determine the mass of the anode after electrolysis. mass of anode = ……………………… g [1] (c) In a second experiment, graphite electrodes were used instead of copper electrodes in the same set-up and electrolyte. (i) Write an ionic equation, including state symbols, for the reaction that happen at the anode. ……………………………………………………………………………... [1] (ii) Describe one similarity observed at the electrode(s) used in both experiments. ……………………………………………………………………………... ……………………………………………………………………………... [1] (iii) State and explain the colour observed when a few drops of Universal Indicator were added to the electrolyte at the end of the electrolysis. …………………………………………………………………………….. …………………………………………………………………………….. …………………………………………………………………………….. ……………………………………………………………………………... [2] [Total: 9]

7 6092/02/4E/PRELIM/2024 [Turn over 5 The diagrams show the structure of six organic compounds. (a) Define the term isomer. Use your definition to show which of the above compounds are isomers of each other. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………