2024 LSS 2EXP EOY Section B&C

Full Name Class Class Index No. Anglo-Chinese School (Barker Road) END-OF-YEAR EXAMINATION 2024 SECONDARY TWO EXPRESS SCIENCE Total Duration for All Sections: 2 hours SECTIONS B & C INSTRUCTIONS TO CANDIDATES: Write your name, class and index numbers in the space provided at the top of this page. Write in dark blue or black pen. You may use a pencil for any graphs. The use of an approved scientific calculator is expected, where appropriate. Do not use glue or correction fluid. Sections B and C Answer all questions in the spaces provided. INFORMATION FOR CANDIDATES: The number of marks is given in brackets [ ] at the end of each question or part question. This question paper consists of 17 printed pages. For Examiner's Use Section A /30 Section B /40 Section C /30 Total /100

End-of-Year Examination 2023 2 Secondary 2 Express Science SECTION B (40 marks) Answer all the questions in the spaces provided. B1 Table 1.1 shows some information about two different substances, P and Q. Table 1.1 substance information solid P It is made of three different elements combined in a fixed ratio. P is soluble in water. powder Q It is made up of a mixture of grey and yellow powder that are both insoluble in water. Only the grey powder is attracted to magnet. (a) Put a tick (√) in the table below to indicate if P and Q is an element, a compound or a mixture. substance element compound mixture solid P powder Q [2] (b) A student accidentally mixed solid P and powder Q in a beaker. Describe the steps needed to obtain powder Q from the mixture. ……………………………………………………………………………………...………… ……………………………………………………………………………………...………… ……………………………………………………………………………………...………… ……………………………………………………………………………………...………… ……………………………………………………………………………………...………… [3] (c) Table 1.2 shows three substances and their chemical formulae. Table 1.2 substance chemical formula number of atoms nitrogen gas N2 ethene C2H4 sulfuric acid H2SO4 Complete Table 1.2 to show the number of atoms for each substance. [3] [Total: 8]

Anglo-Chinese School (Barker Road) End-of-Year Examinations 2024 3 Secondary 2 Express Science B2 Fig. 2.1 shows an experiment conducted to investigate how the temperature of water affects the rate at which salt dissolves in water. Fig. 2.1 (a) (i) Identify the independent variable in the experiment. ………………………………………………………………………………………. [1] (ii) Identify one variable that is kept constant in the experiment. ………………………………………………………………………………………. [1] (b) State which beaker’s salt dissolves the fastest. Explain your answer. ……………………………………………………………………………………...………… ……………………………………………………………………………………...………… ……………………………………………………………………………………...………… ……………………………………………………………………………………...………… [2] [Total: 4] beaker X 30 cm3 of water 30 °C glass rod 10 g of fine salt beaker W 30 cm 3 of water 20 °C glass rod 10 g of fine salt beaker Z 30 cm 3 of water 50 °C glass rod 10 g of fine salt beaker Y 30 cm 3 of water 40 °C glass rod 10 g of fine salt

Anglo-Chinese School (Barker Road) End-of-Year Examinations 2024 4 Secondary 2 Express Science B3 Fig. 3.1 shows an individual looking at an object in the mirror. Fig. 3.1 (a) In Fig. 3.1, draw the ray diagram and locate the position of the image. [3] (b) State two properties of an image formed on a mirror. 1 ……………………………………………………………………………………...… 2 ……………………………………………………………………………………...… [2] [Total: 5] eye plane mirror object

Anglo-Chinese School (Barker Road) End-of-Year Examinations 2024 5 Secondary 2 Express Science B4 Fig. 4.1 shows a flowchart for five different reactions with dilute nitric acid. Five unknown substances A, B, C, D and E are added to the dilute nitric acid as shown below. Fig. 4.1 (a) Use the letters A, B, C, D and E only, match the substance to the following based on the chemical reactions shown in Fig. 4.1. (i) calcium carbonate ……………………………. (ii) iron ……………………………. (iii) Universal indication solution ……………………………. [3] (b) State a difference between chemical and physical reaction. ……………………………………………………………………………………...………. ……………………………………………………………………………………...………. [1] [Total: 4] dilute nitric acid salt + carbon dioxide + water red solution salt + hydrogen gas salt + water blue solution A B C D E

Anglo-Chinese School (Barker Road) End-of-Year Examinations 2024 6 Secondary 2 Express Science B5 Fig 5.1 shows a sequence of steps in the experiment to investigate the fat content of several milk samples. The pH indicator used is colo urless when the pH is 7 or less, and purple when the pH is over 7. (a) (i) State one product of digestion of fat by lipase. ……………………………………………………………………………………......... [1] (ii) Explain how the action of lipase led to the indicator losing its colour. ……………………………………………………………………………………......... ……………………………………………………………………………………......... [1] (b) A student was tasked to conduct the experiment as shown in Fig. 5.1 using three different samples of goat’s milk. The time taken for the purple colour to disappear was recorded. The experiment for each sample was repeated once. Table 5.2 shows the time taken for the purple colour to disappear. Table 5.2 experiment time taken for indicator to lose its colour / min sample A sample B sample C 1 5 3 4 2 6 4 5 (i) Briefly explain why the experiment was conducted twice. ………………………………………………………………...................................... ………………………………………………………………...................................... [1] (ii) With reference to Table 5.2, write down the three milk samples in decreasing order of fat content, from highest to lowest. ………………………………………………………………...................................... [1] [Total: 4] thermometer 2 drops of pH indicator added 1 cm3 of lipase added 5 cm3 milk milk turns purple start of experiment: purple colour end of experiment: purple colour disappears Fig. 5.1 water bath

Anglo-Chinese School (Barker Road) End-of-Year Examinations 2024 7 Secondary 2 Express Science B6 Fig. 6.1 shows an image of red blood cells. Fig. 6.1 (a) (i) State the function of a red blood cell. …………………………………………………………………………………………... [1] (ii) Describe one way in which a red blood cell is adapted for its function. …………………………………………………………………………………………... …………………………………………………………………………………………... …………………………………………………………………………………………... …………………………………………………………………………………………... [2] (b) State the component of blood responsible for clotting. ………………………………………………………………………………………………… [1]

Anglo-Chinese School (Barker Road) End-of-Year Examinations 2024 8 Secondary 2 Express Science (c) Fig. 6.2 shows a diagram of the circulatory system. The blood vessels are labelled with letters. Fig. 6.2 With reference to Fig. 6.2, state all letters that represent the following: (i) arteries …………………………………………………………………………………………... [1] (ii) veins …………………………………………………………………………………………... [2] [Total: 7] lungs heart kidneys legs G A A F B A E C A D

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