2024 Fuhua Sec 4E Chemistry P2

Candidate Name: Class: Index No.: FUHUA SECONDARY SCHOOL Secondary Four Express PRELIMINARY EXAMINATION 2024 4E Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Seco ndary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fu hua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Seco ndary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuh ua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Secondary School Fuhua Seco ndary School CHEMISTRY 6092/2 Paper 2 DATE 16 August 2024 TIME 1045 - 1230 DURATION 1 hour 45 minutes READ THESE INSTRUCTIONS FIRST Write your name, class and index number on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided. Section B 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. A copy of the Periodic Table is printed on page 24. The use of an approved scientific calculator is expected, where appropriate. PARENT’S SIGNATURE FOR EXAMINER’S USE Section A Section B Total /70 /10 /80 This document consists of 23 printed pages and 1 blank page.

2 Section A Answer all questions. 1 Fig. 1.1 shows ‘dot -and-cross’ diagrams for molecule 1, 2 and 3 that contain elements from Period 2 and 3 of the Periodic Table. The elements are represented by the letters M, Q, R, T and Z. Each diagram shows outer electrons only. molecule 1 molecule 2 molecule 3 Fig. 1.1 (a) Which elements are in Group 17? [1] (b) What is the formula of the compound formed between Z and T? [1]

3 (c) (i) Draw a ‘dot-and-cross’ diagram to show the bonding of the compound formed between element P and R. [2] (ii) Draw a ‘dot-and-cross’ diagram to show the bonding of the compound formed between magnesium and element M. [2] (d) The following are some statements about the substances in Fig. 1.1. Put a tick (✓) in one box in each row to show which statements are true and which are false. true false Molecule 3 has lower boiling point then molecule 2. Molecule 3 is a saturated organic compound. Only element Z reacts with oxygen to form acidic oxide. Elements P and T are in Group 16. [2] [Total: 8]

4 2 Three experiments were carried out to measure the rate of reaction between excess barium carbonate powder and a strong monobasic acid. The reaction produces a gas which escapes from the reaction flask. The ionic equation for the reaction is BaCO3 (s) + 2H+ (aq) → Ba2+ (aq) + H2O (l) + CO2 (g) The rate of reaction was followed by measuring the change in mass of the reaction flask at regular time intervals. The results of the three experiments are shown in the Fig. 2.1. Fig. 2.1 (a) (i) Calculate the number of moles of carbon dioxide gas produced in experiment 1. [1] (ii) Hence, deduce and state the conditions of each experiment by completing the table below. experiment particle size volume of acid / cm3 concentration of acid / moldm-3 1 powder 2.0 2 lumps 1.0 3 [3]

5 (b) Explain, in terms of reacting particles, how particle size of barium carbonate affects the rate of the reaction. [2] (c) The acid used is either hydrochloric acid or nitric acid. Describe a test to confirm the identity of the acid used. [1] (d) A further experiment, experiment 4, was carried out using ethanoic acid of the same volume and concentration as experiment 1. Predict and explain how the rate of reaction and change in mass of the reaction flask of experiment 4 would be different from experiment 1. [3] [Total: 10]

6 3 Electrolysis is commonly used to give an object an attractive appearance or to prevent corrosion of a metal. Fig. 3.1 shows a set -up prepared to electroplate an iron object using 200 cm3 of aqueous copper (II) sulfate as the electrolyte. Fig. 3.1 Electrolysis was carried out and Fig. 3.2 shows the concentration of aqueous copper (II) sulfate against time. Fig. 3.2

7 (a) (i) Explain the shape of the graph by using an appropriate half-equation to support your answer. [2] (ii) Using data from the graph, calculate the increase in mass of the iron object after the electrolysis was conducted for 80 minutes. [2] (b) The set-up was modified as shown in Fig. 3.3 below. Electrolysis was conducted using the same quantity of electricity as in the previous set-up. Fig. 3.3 (i) Sketch a graph, on Fig. 3.2, to show the concentration of aqueous copper (II) sulfate against time in cell A for the set-up in Fig. 3.3. The initial concentration of aqueous copper (II) sulfate was same as the set -up in Fig. 3.1. Label your graph clearly. [1] (ii) Describe the observations at the graphite and iron electrodes in cell B. [2]

8 (c) Sheets of iron are coated in tin and made into tin cans. The cans are filled with pineapple pieces and water. One of the cans becomes “dented” and the tin coating is scratched. Suggest why the can corrodes more rapidly when it has a dent on its side compared to a pure iron can. [2] [Total: 9] 4 (a) Table 4.1 shows information about some organic compounds. Complete the table by filling in the missing names, formulae and by completing the description of the processes. name of compound structural formula process(es) used to produce the compound Warming of _________________ and _________________________ with concentrated sulfuric acid. propane Catalytic _________________________ to propene. polybutene __________________________ of butene nylon-6,6 _________________________ of monomers and . Table 4.1 [5]

9 (b) Alkyl halides are a homologous series of organic compounds. They are formed when one halogen atom (X = Cl, Br, I) bonds with carbon atoms. Table 4.2 shows the condensed formulae and boiling points of some alkyl halides. condensed formula boiling point / C X Cl Br I CH3X -24.2 3.6 42.4 CH3CH2X 12.3 38.4 72.3 CH3CH2CH2X 46.6 71.0 102.5 CH3CH2CH2CH2X 78.4 101.6 130.5 Table 4.2 (i) Besides having the same functional group, use the information in the table to give two other pieces of evidence that suggest that the alkyl halides are a homologous series. [2] (ii) Describe and explain the trend in boiling points of alkyl halides when the halogen atom changes from Cl to I. [3]

10 (iii) Alkyl halides can be prepared by the reaction of halogen acids with alcohols. For example, hydrochloric acid reacts with methanol to produce methyl chloride and water. Write an equation for the preparation of ethyl iodide , showing all the displayed formulae of all organic compounds. [2] [Total: 12] 5 Experiments on three metals (copper, manganese and chromium) were conducted. Table 5.1 shows the appearance of the metals and the results of their reactions with air. metal appearance reaction with air copper reddish-brown solid Burns in air to form black copper (II) oxide. m