2025 AES 5086 5088 Sc(Chem) Prelim P3

Name: …………………………………………. ( ) Class: ………………….. [Turn over ASSUMPTION ENGLISH SCHOOL PRELIMINARY EXAMINATION 2025 SCIENCE (CHEMISTRY) 5086 / 03 5088 / 03 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 / Sec 5 Normal (Academic) DATE : 29 August 2025 CLASS(ES): Sec 4/2, 4/3, 4/5 SBB, 5/1 DURATION : 1 hour 15 minutes Additional Materials Provided: NIL INSTRUCTIONS TO CANDIDATES Do not open this booklet until you are told to do so. Write your NAME, CLASS and INDEX NUMBER at the top of this page. This paper consists of 2 sections. Section A (55 marks) Answer all questions. Write your answers in the spaces provided on the question paper. Section B (10 marks) Answer one question. Write your answers in the spaces provided on the question paper. The number of marks is given in brackets [ ] at the end of each question or part question. A copy of the Data Sheet is printed on page 16. A copy of the Periodic Table is printed on page 17. The use of an approved scientific calculator is expected, where appropriate. For Examiner’s use: Section A / 55 Section B / 10 Paper 3 / 65 Paper 1 / 20 Paper 5 / 15 Total / 100 This question paper consists of 17 printed pages including this page.

2 5086/5088/03/4E/5N/PRELIM/25 Section A Answer all the questions in the spaces provided. 1 Choose from the following substances to answer the questions. ammonia carbon monoxide silver sulfate aluminium oxide copper sulfur calcium hydroxide methane sulfur dioxide Each substance may be used once, more than once or not at all. Identify a substance which (a) is a toxic gas that combines with haemoglobin in red blood cells, ……………………………………………………………………………………. [1] (b) is a gas that contributes to the formation of acid rain, ……………………………………………………………………………………. [1] (c) reacts with both acids and alkalis, ……………………………………………………………………………………. [1] (d) is an element which forms X2- ion, ……………………………………………………………………………………. [1] (e) is used to reduce the acidity of soils, ……………………………………………………………………………………. [1] (f) is a greenhouse gas. ……………………………………………………………………………………. [1] [Total: 6]

3 5086/5088/03/4E/5N/PRELIM/25 [Turn over 2 The table below contains details of seven different particles. The letters are not the chemical symbols of the elements. particles mass number proton number number of electrons A 4 2 2 B 12 6 6 C 14 6 6 D 14 7 10 E 24 12 10 F 19 9 9 (a) State which particles A, B, C, D, E or F from the table (i) is a negatively charged ion, …………………… [1] (ii) is an ion of an element in group 2, …………………… [1] (iii) is an unreactive gas. …………………… [1] (b) Two particles in the table are isotopes of the same element. (i) Identify the two particles that are isotopes of the same element. ………………… and ………………….. [1] (ii) Do both isotopes have the same chemical reactivity? Explain your answer. ……………………………………………………………………………. [1] (c) Atom B forms a gas when it burns completely in oxygen. (i) Name the gas formed when atom B burns completely in oxygen. ……………………………………………………………………………. [1] (ii) Suggest the type of bonding present in the gas in (c)(i) and explain why it exists as a gas at room temperature and pressure. ……………………………………………………………………………. ……………………………………………………………………………. ……………………………………………………………………………. [2] [Total: 8]

4 5086/5088/03/4E/5N/PRELIM/25 3 The table shows some information about four different substances, A, B, C and D when heated. Complete the table by identifying whether substances, A, B, C and D is an element, compound or mixture. substance melting point/ °C colour other information element, compound or mixture A −10 to −6 green A colourless gas is given off. A greenish-white solid is left behind. Another gas condenses into water droplets on the sides of the test tube. B 105 white It melts into a colourless liquid and turns brown on further heating. Finally, a black residue is left behind. C 115 yellow It cannot be decomposed into anything simpler. D 242 blue A black solid is formed and a gas is given off. [4] [Total: 4] 4 The table below describes and names different types of reactions. Complete the table with the correct type of reactions. The first reaction has been completed for you. description of reaction type of reaction many monomers forming a polymer polymerisation changing long-chain hydrocarbons into short-chain hydrocarbons dead organic substances are broken down into simpler matter releases energy, often in the form of heat to the surrounding [3] [Total: 3]

5 5086/5088/03/4E/5N/PRELIM/25 [Turn over 5 The table below shows the melting and boiling points of three substances. substance melting point / C boiling point / C solubility in water P −85 215 yes Q −62 70 yes R 22 672 no (a) Describe the changes in movement and arrangement of substance R when it is heated from 30 C to 700 C. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [2] (b) Sketch a graph of temperature versus time to show the change in temperature when substance P is heated from −100 °C to 150 °C. Label the axes. [2] (c) (i) Suggest a suitable method to separate a mixture of P and Q. …..………………………………………………………………………... [1] (ii) Explain your answer in (c)(i). …..………………………………………………………………………... …..………………………………………………………………………... [1] [Total: 6]

6 5086/5088/03/4E/5N/PRELIM/25 6 Four food colourings, W, X, Y and Z were analysed using paper chromatography. The diagrams below show the chromatograms obtained with water and ethanol as the solvent respectively. (a) Which food colouring(s) is / are mixtures? Explain your answer. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [1] (b) Explain why the start line must be drawn in pencil. ……………………………………………………………………………………. ……………………………………………………………………………………. [1] [Total: 2] solvent front start line water as solvent ethanol as solvent

7 5086/5088/03/4E/5N/PRELIM/25 [Turn over 7 The structure of magnesium oxide, an insoluble base is shown in the diagram below. (a) Explain why solid magnesium oxide does not conduct electricity. ……………………………………………………………………………………. ……………………………………………………………………………………. [1] (b) Complete the following table which gives information about the two ions. ion number of protons number of neutrons number of electrons nucleon (mass) number O2- 8 8 Mg2+ 10 24 [2] (c) Draw a ‘dot-and-cross’ diagram to show the bonding in m