PRSS Sec 2 Science 2024 EOY (P2)

This document consists of 18 printed pages, including the cover page. Setter: Mr W. Chiang & Ms Quah WW [Turn over Pasir Ris Secondary School Name: Class: Register Number: SECONDARY 2 EXPRESS END OF YEAR EXAMINATION 2024 LOWER SECONDARY SCIENCE Paper 2 Theory Thursday 0800 – 1000 Additional Materials: Nil 03 October 2024 Papers 1 and 2: 2 hours READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces provided at the top of this page. Do not use staples, paper clips, highlighters, glue, correction fluid or tape. The use of an approved scientific calculator is expected, where appropriate. Section A [30 marks] Answer all questions. Write your answers in the spaces provided. Section B [40 marks] There are five questions in this section. Answer any four questions. Write your answers in the spaces provided. You may proceed to answer Paper 2 as soon as you have completed Paper 1. A copy of the Periodic Table is printed on Page 12 of Paper 1. At the end of the examination, hand in your answers to Paper 1 and Paper 2 separately. The number of marks is given in brackets [ ] at the end of each question or part question. For Candidate’s Use For Examiner’s Use Circle the numbers of the four questions you have attempted in Section B. Section A 30 Section B 40 7 8 9 10 11 Total 70

PRSS_2024_2E_EOY_SCIENCE_P2 [Turn over 2 [Turn over Section A (30 marks) Answer all the questions. Write your answers in the spaces provided. 1 Paper chromatography is a fast and easy way to determine if samples are pure. Fig. 1.1 shows a chromatogram with sample A using water as the solvent. Fig. 1.1 (a) Identify the most soluble spot in water. ….…………….………….……...…….….…….…..….…..……..…….….….........……....….........…[1] (b) The chromatogram is turned 90° and another solvent (solvent P) is used to dissolve spots 1, 2 and 3. The results are shown in Fig. 1.2. Fig. 1.2 (i) Explain why no spot was found above spot 1 in Fig. 1.2. ……………………………………………………………………………………………………...[1]

PRSS_2024_2E_EOY_SCIENCE_P2 [Turn over 3 [Turn over (ii) State the number of components present in sample A. …………………………….………………………………………………………………………. [1] (iii) State one other conclusion that can be made about spots 2 and 3. ………………………………………………………………………………………………..………. ………………………………………………………………………………………………………[1] [Total: 4] 2 Mirrors can be used to produce different effects with light. (a) State the two characteristics of reflection in the ray model of light. ……………………………………………..……………………………………………………………….. ……………………………………………………..……………………………………………………….. ……………………………………………………………………………………………………………[2] (b) Fig. 2.1 shows a ray diagram of a type of mirror. Fig. 2.1 (i) State the type of mirror used in Fig. 2.1. ………………………………………………………………………………………………………[1] (ii) State two characteristics of the image formed by the mirror in Fig. 2.1. ……………………………………………………..………………………………………………….. ………………………………………………………………………………………………………[2] [Total: 5] object image eye mirror

PRSS_2024_2E_EOY_SCIENCE_P2 [Turn over 4 [Turn over 3 Fig. 3.1 shows the diagram of a bacterial cell. Fig. 3.1 (a) State one way in which the bacterial cell is similar to a typical plant cell but not a typical animal cell. ………………………………………………………………………….…………….……….…….……… ….…………….………….……...…….….…….…..….…..……..…….….….........……....….........…[1] (b) State one way in which the bacterial cell is different from both typical animal and plant cells. ………………………………………………………………………….…………….……….…….……… ….…………….………….……...…….….…….…..….…..……..…….….….........……....….........…[1] (c) Using information from Fig. 3.1, state and explain if the bacterial cell is able to make its own food. ………………………………………………………………………….…………….……….…….……… ………………………………………………………………………….…………….……….…….……… ………………………………………………………………………….…………….……….…….……… ….…………….………….……...…….….…….…..….…..……..…….….….........……....….........…[2] [Total: 4] cell wall DNA cytoplasm

PRSS_2024_2E_EOY_SCIENCE_P2 [Turn over 5 [Turn over 4 The melting and boiling points of some substances are given in Table 4.1. Table 4.1 substance melting point/ ºC boiling point/ ºC A -81 400 B -79 -79 C 46 280 D 87 450 E 1,255 2,150 (a) Draw the arrangement of the particles of substance A at room temperature in a box shown in Fig. 4.2. Fig. 4.2 [1] (b) State the substance which sublimes on heating. ….…………….………….……...…….….…….…..….…..……..…….….….........……....….........…[1] (c) Describe the arrangement and movement of the particles in substance E at room temperature and pressure. arrangement ………………………………………………………………………………………………. ………………………………………………………………………………………………………………. movement …………………………………………………………………………………………………. ….…………….………….……...…….….…….…..….…..……..…….….….........……....….........…[2] (d) Explain why pure substance D melts at a fixed temperature of 87°C. ………………………………………………………………………….…………….……….…….……… ….…………….………….……...…….….…….…..….…..……..…….….….........……....….........…[1] [Total: 5] 5 Copper sulfate crystals were made using the following method. One spatula of copper carbonate was added to 20 cm3 of acid X. Once it had all reacted, more copper carbonate was added until no more gas was given off. The reaction mixture was filtered. The filtrate was evaporated to about half its volume and then allowed to cool. The crystals were filtered out and dried. (a) (i) Name the gas given off when copper carbonate reacted with acid X. ………………………………………………………………………………………………………[1]

PRSS_2024_2E_EOY_SCIENCE_P2 [Turn over 6 [Turn over (ii) Describe a test to identify the gas stated in (a)(i). test ………………………………………………………………………………………………….… ………………………………………………………………………………………………………… observations ..……………………………………………………………………………..………… ………………………………………………………………………………………………………[2] (b) Identify acid X. Hence, write a word equation for the chemical reaction between X and copper carbonate. acid X ……………………………………………. word equation …………………………………………………………………………………………….. [2] (c) Describe a simple method to check that the crystals have a neutral pH. ……………………………………………………………………………………………………………… ….…………….………….……...…….….…….…..….…..……..…….….….........……....….........…[1] [Total: 6] 6 (a) Fig. 6.1 shows a solar panel used to heat water. Fig. 6.1 (i) State the process by which thermal energy is transferred from the Sun to the solar panel. ….…………….………….……...…….….….….…..…..…..….…..…….…..…...........…..........[1] water storage tank water pipe under solar panel solar panel

PRSS_2024_2E_EOY_SCIENCE_P2 [Turn over 7 [Turn over (ii) State and explain one improvement to the solar panel so that the solar energy can be absorbed more efficiently. ………………………………………………………………….……….…………….……….……... ………………………………………………………………….……….…………….……….……... ………………………………………………………………….……….…………….……….……... ….…………….………….……...…….….….….…..…..…..….…..…….…..…...........…..........[2] (iii) State the most suitable material used for the water pipe. Give a reason for your choice. ………………………………………………………………….……….…………….……….……... ….…………….………….……...…….….….….…..…..…..….…..…….…..…...........…..........[1] (b) A pack which contains a frozen liquid is placed under the lid of a box as shown in Fig. 6.2. The box is then used to keep the apple cold. Fig. 6.2 Explain why the pack is placed at the top rather than at the bottom of the box. ………………………………………………………………………