Science (Chemistry) 5105/04 OR 5107/04 Kranji Secondary School 2024

Candidate Name: __________________________ ( ) Class: _________ KRANJI SECONDARY SCHOOL Preliminary Examination Secondary 4 Normal (Academic) SCIENCE (CHEMISTRY) 5105/04 Paper 4 5107/04 Papers 3 and 4 Friday 2 August 2024 1 hour 15 minutes KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI SECONDARY KRANJI READ THESE INSTRUCTIONS FIRST Write your name, index number and class 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 use of an approved scientific calculator is expected, where appropriate. In calculations, you should show all the steps in your working, giving your answer at each stage. You are advised to spend no longer than 30 minutes on Paper 3. You may proceed to answer Paper 4 as soon as you have completed Paper 3. A copy of the Periodic Table is printed on page 11. At the end of the examination hand in your answers to Paper 3 and Paper 4 separately. The number of marks is given in brackets [ ] at the end of each question or part question. Set by: Mr Joel Lee This Question Paper consists of 11 printed pages and 1 blank page. [Turn over For Examiners’ Use Paper 3 20 Paper 4 30 Total 50 4NA Session 1

2 Section A Answer all the questions in the spaces provided. 1 Several substances are listed below. sulfur dioxide iodine zinc hydrochloric acid brass ammonium nitrate helium sodium hydroxide methane Answer the following questions using the substances from the list. Each substance may be used once, more than once, or not at all. (a) Which substance is a mixture of elements? ………………………………………………………………………………………………. [1] (b) Which substance is a monoatomic gas? ………………………………………………………………………………………………. [1] (c) Which substance is a major greenhouse gas that contributes to global warming? ………………………………………………………………………………………………. [1] (d) Which two substances react to form ammonia gas? ………………………………………………………………………………………………. [1] [Total: 4]

3 [Turn over 2 The table below shows the boiling point s of nitrogen, oxygen and argon, which can be obtained from liquid air. Liquid air is air that is cooled until it liquefies. gas melting point / °C nitrogen -196 oxygen -183 argon -186 (a) State the separation process used to obtain these gases from liquid air. ………………………………………………………………………………………………. [1] (b) State the gas that is collected first during this process. ………………………………………………………………………………………………. [1] (c) At high temperatures in car engines, two of these gases react to form a common atmospheric pollutant. (i) State the name of this pollutant. ………………………………………………………………………………………….. [1] (ii) State another air pollutant commonly produced in car engines and its health effects. pollutant …………………………………………………………………………………... health effects ……………………………………………………………………………... .…………………………………………………………………………………………. [2] [Total: 5]

4 3 The table below lists some information of three metal elements beryllium, magnesium and calcium. metal proton number electronic configuration beryllium 2 magnesium 12 calcium 20 (a) Complete the table by stating the electronic configuration of the metals. [1] (b) Based on your answers in part (a) , explain why these metals are in the same Group of the Periodic Table. …………………………………………………………………………………………………. ………………………………………………………………………………………………. [1] (c) Calcium reacts with chlorine to form calcium chloride. (i) Draw a dot-and-cross diagram to show the bonding in calcium chloride. Show outer shell electrons only. [Proton (atomic) numbers: Ca, 20; Cl, 17] [2] (ii) State one difference between the electrical conductivity of calcium and calcium chloride. ……………………………………………………………………………………………... ……………………………………………………………………………………………... .…………………………………………………………………………………………..[1] [Total: 5]

5 [Turn over 4 A student wanted to study the reaction between a metal and an acid. He set up an experiment as shown below. The reading on the electronic balance is recorded every two minutes. The results are shown in the table below. time/min 0 2 4 6 8 10 reading on balance / g 4.00 2.50 1.60 1.00 0.70 0.70 (a) The reaction between zinc and hydrochloric acid produces a gas. State the name of the gas and describe a chemical test to confirm its identity. name of gas .………………………………………………………………………………….. positive test for this gas ..…………………………………………………………………….. ………………………………………………………………………………………………….. ………………………………………………………………………………………………. [2] (b) Suggest why the reading on the electronic balance decreases with time. …………………………………………………………………………………………………. ………………………………………………………………………………………………. [1] dilute hydrochloric acid cotton wool zinc pieces electronic balance conical flask

6 (c) Plot a graph of the reading on the balance against time. Mark each point with a cross (×). [1] (d) Draw a curved line of best fit taking into account all your plotted points. [1] (e) Use your graph to estimate the time that the reaction is completed. ………………………………. min [1] (f) Another way of studying this reaction is to collect and measure the volume of gas produced as the reaction proceeds. State a suitable piece of apparatus for this. …...……………………………………………………………………………………………… [1] (g) The student wanted to repeat the experiment with another metal and suggested using sodium. Explain why this should not be done. ……………………………………………………………………………………………………… …...……………………………………………………………………………………………… [1] [Total: 8] 4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 reading on balance / g 0 1 2 3 4 5 6 7 8 9 10 time /min

7 [Turn over Section B Answer one question from this section. 5 Elements W, X, Y and Z are in Group 17 of the Periodic Table. The table below shows the properties of the elements and their reactions with their corresponding W-, X-, Y- and Z- ions. element state at room temperature reaction with W- ion reaction with X- ion reaction with Y- ion reaction with Z- ion W × ✓ ✓ ✓ X liquid × × ✓ × Y solid × × × × Z gas × ✓ ✓ × key: ×: no reaction; ✓: reaction took place (a) Arrange the elements W, X, Y and Z in order of increasing reactivity. ………………………………………………………………………………………………. [1] (b) Predict the state of element W at room temperature. ………………………………………………………………………………………………. [1] (c) Group 17 elements exist as diatomic molecules. (i) Draw a dot-and-cross diagram to show one molecule of fluorine. Show only outer shell electrons. [Proton (atomic) number: F: 9] [2]

8 (ii) Explain why the elements in Group 17 have low melting points. …..…………………………………………………………………………………………. ……………………………………………………………………………………………... .…………………………………………………………………………………………….. .…………………………………………