2023 XMS P2 PRELIM QP

3 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use Section A Answer all questions in this section in the spaces provided. The total mark for this section is 50. A1 The diagram shows part of the Periodic Table. Answer the questions using only the elements shown in the diagram. Each element may be used once, more than once or not at all. Write the symbol for an element which: (a) (i) forms an ion of type X2−, ……………………………………………………………………………………. [1] (ii) is a diatomic green gas at room temperature, ……………………………………………………………………………………. [1] (iii) is a gas used for weather balloons, ……………………………………………………………………………………. [1] (iv) is a gas which occupies 78% by volume of dry air, ……………………………………………………………………………………. [1] (v) can have lubricating properties. ……………………………………………………………………………………. [1] (b) Modern chemists have discovered that some noble gases can form compounds. A 1.000 g sample of one such compound is found to contains 0.549 g of xenon, 0.134 g of oxygen and 0.317 g of fluorine. (i) Calculate the empirical formula of this compound. [2]

4 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use (ii) What additional information is needed to deduce the molecular formula of this compound? ……………………………………………………………………………………. [1] (c) Draw a ‘dot -and-cross’ diagram to show the bonding in a molecule of oxygen . Show the outer electrons only. [2] (d) Aluminium and sulfur can react with oxygen to form oxides. Suggest one difference in physical property and one difference in chemical property between the oxide of aluminium and the oxide of sulfur. physical property ………………………………………………………………………………………..…. ………………………………………………………………………………………..…. chemical property ………………………………………………………………………………………..…. ………………………………………………………………………………………..…. [1] [1] [Total: 12]

5 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use A2 (a) A student investigated the reaction between different metals and hydrochloric acid. He reacted 1.5 g of iron and 1.5 g of zinc separately with excess hydrochloric acid. Fe(s) + 2HCl(aq) → FeCl2(aq) + H2(g) Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g) Every 10 seconds, he measured the volume of gas in a gas syringe. The graph shows the results. (i) Explain why 1.5 g of iron produces more hydrogen gas than 1.5 g of zinc. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [2] (ii) Explain how you can tell from the graph which is the more reactive metal. ……………………………………………………………………………………. [1]

6 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use (iii) When the reaction stops, the student adds aqueous sodium hydroxide drop by drop to the solution in the conical flask until it is in excess. Describe what you would observe during the addition of aqueous sodium hydroxide for each experiment. experiment with iron: ……………………………………………………………………………………. ……………………………………………………………………………………. experiment with zinc: ……………………………………………………………………………………. ……………………………………………………………………………………. [3] (b) Another student used the apparatus below to coat a thin layer of copper on a steel knife. The knife was cleaned carefully and all grease removed before the process started. (i) The steel blade of the knife acts as a cathode. Copper(II) ions from the solution form copper on the blade surface. Write an equation, with state symbols, for this reaction. ……………………………………………………………………………………. [2] (ii) What will happen to the concentration of the copper(II) in the solution during electrolysis if the anode bar is made of carbon? ……………………………………………………………………………………. [1] (iii) What will happen to the concentration of the copper(II) ions in the solution during electrolysis if the anode bar is made of copper? ……………………………………………………………………………………. [1] [Total: 10] anode bar aqueous copper(II) sulfate

7 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use A3 (a) ‘Superglue’ contains the following monomer. The monomer is rapidly polymerised by traces of bases on the surfaces of objects to be stuck together, causing the glue to set solid. (i) What type of polymerisation takes place when the glue is in use? ……………………………………………………………………………………. [1] (ii) Draw a repeat unit of the polymerised form of the glue. [1] (iii) Show by calculations that the polymer contains more than 50% by mass of carbon. [2] H C N C H C C CH3 O O

8 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use (b) An experiment is carried out to find out how changing the temperature changes the time taken for the glue to harden (the setting time). The graph below shows the results of the experiment. (i) At what temperature does the glue take 10 minutes to set? ……………………………………………………………………………………. [1] (ii) Describe how the setting time changes as the temperature increases. Explain your answer in terms of particles. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [3] (iii) The experiment is repeated using glue containing a higher monomer concentration. Draw a curve on the graph to show the results you would expect. Label the curve ‘higher concentration’. [1] [Total: 9] 50 10 20 30 40 0 60 70 5 10 15 20 25 30 0 35 setting time / minutes temperature / oC

9 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use A4 (a) A student was given tin, iron, copper and zinc and solutions of the metal sulfates. Using a dropper, she put a little of one of the sulfate solutions in four of the depressions of a well plate. She did this for each solution in turn. She then put a piece of metal foil in each of the solutions, as shown below. (i) Put a tick ( ✓) next to the question which best describes the investigation the student is carrying out. Which displacement is the most exothermic? Which metal can displace copper from solution? What is meant by the reactivity series? What are the positions of the four metals in the reactivity series? [1] well plate

10 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use (ii) The student recorded the results by putting a tick ( ✓) next to a mixture which showed signs of a reaction and a cross (X) next to a mixture which showed no signs of a reaction. The student concluded that: tin displaces copper iron displaces tin iron displaces copper zinc displaces iron Give the letter of the plate below which shows her results. ………………….. [1] (iii) Write an ionic equation for any of the reactions. [1] (iv) Another student said that not all of the tests carried out were necessary. Give one example of a test not needed. Explain your choice. example …………………………………………………………………………. explanation ……………………………………………………………………… [2]

11 6092/Chemistry/Paper 2/2023 Prelim Exam For Examiner’s Use (b) When a mixture of iron(III) oxide and aluminium powder (Thermit mixture) is heated, there is a violent reaction. The reaction is