Science Stage 9 Paper 2 2024 45 minutes No additional materials are needed. INSTRUCTIONS • Answer all questions. • Write your answer to each question in the space provided. • You should show all your working on the question paper. INFORMATION • The total mark for this paper is 50. • The number of marks for each question or part question is shown in brackets [ ]. 3146_02_7RP © UCLES 2024 2 1 Look at the diagram of part of the cross-section of a plant leaf. upper layer palisade layer vein spongy layer lower layer stoma (a) The palisade layer contains many chloroplasts. (i) What process happens inside chloroplasts? [1] (ii) Name two gases exchanged through the stoma. 1 2 [2] (b) Chloroplasts contain chlorophyll. What is the function of chlorophyll? [1] © UCLES 2024 S/S9/02 3 2 The diagram shows a model of the atomic structure of a sodium atom and a chlorine atom. Na Cl A sodium atom and a chlorine atom react together to make a sodium ion, Na+, and a chloride ion, Cl –. (a) Describe how a sodium atom and a chlorine atom become charged ions. sodium atom chlorine atom [2] (b) Describe how ions are held together in an ionic compound. [2] © UCLES 2024 S/S9/02 [Turn over 4 3 This question is about thermal transfer. Decide if each sentence is true or false. Tick () the correct box. sentence true false Heat is the word used to measure how hot an object is. Thermal energy is measured in °C. When thermal energy is transferred, more thermal energy is created. Thermal energy always transfers from hotter objects to colder objects. Heat dissipation happens when thermal energy transfers from a hotter region to a colder region. A liquid is a good thermal energy conductor. Convection happens in liquids and gases only. Radiation needs particles to transfer thermal energy. [4] © UCLES 2024 S/S9/02 5 4 Look at the diagram of a model of the Earth’s crust and upper mantle. crust X upper mantle (a) Name one event that happens at X. [1] (b) What do the arrows on the diagram represent? [1] © UCLES 2024 S/S9/02 [Turn over 6 5 The diagram shows a circuit with two lamps. Complete the circuit diagram to show how to measure the voltage across one of the lamps. © UCLES 2024 S/S9/02 [2] 7 6 Safia is making a salt called copper chloride. She adds insoluble copper carbonate to dilute hydrochloric acid. Water and carbon dioxide are also produced. (a) Write the word equation for this reaction. [2] (b) Complete the information about the method Safia uses to make copper chloride. Safia: • adds excess copper carbonate to dilute hydrochloric acid • separates the excess copper carbonate from the reaction mixture by • pours the filtrate into an evaporating basin • obtains a saturated solution from the filtrate by • leaves the saturated solution in a warm place to . [3] (c) Suggest one piece of safety equipment Safia uses when making copper chloride. [1] © UCLES 2024 S/S9/02 [Turn over 8 7 Mike investigates the temperature of a classroom every day for five days. Look at the table of his results. day temperature in °C 1 21.0 2 21.5 3 22.3 4 21.8 5 22.4 (a) Mike starts to plot the results in a bar chart. Complete his bar chart. 23.0 22.0 temperature in °C 21.0 20.0 1 2 3 day 4 5 [2] (b) Carlos tells Mike to measure the temperature twice each day at the same time of day. Explain why this improves the investigation. [1] © UCLES 2024 S/S9/02 9 8 Scientists think the Moon was formed during a collision between the Earth and another small planet. This is called the collision theory for the formation of the Moon. Describe three reasons why rocks collected from the Moon support this collision theory. 1 2 3 [3] © UCLES 2024 S/S9/02 [Turn over 10 9 The diagram shows the genetic material inside an animal cell. A B D C E NOT TO SCALE © UCLES 2024 S/S9/02 11 Look at parts A, B, C, D and E. (a) Circle the letter that shows a chromosome. A B C D E [1] (b) Circle the letter that controls a single characteristic such as eye colour. A B C D E [1] (c) Write down the name of the chemical that is in a chromosome. [1] © UCLES 2024 S/S9/02 [Turn over 12 10 Ahmed wants to find the density of dry sand. The dry sand has a mass of 150 g and a volume of 100 cm3. Calculate the density of the dry sand. Include the unit of density in your answer. density = unit [3] © UCLES 2024 S/S9/02 13 11 Mia investigates an electrical circuit. (a) She makes this prediction, ‘Adding more lamps into a series circuit does not change the current in the circuit.’ Tick () to show if Mia's prediction is correct. yes no Give a reason for your answer. [1] (b) The current flowing through a lamp is 4.5 A. The voltage across the lamp is 1.5 V. Calculate the resistance of the lamp. resistance = © UCLES 2024 S/S9/02 Ω [2] [Turn over 14 12 (a) A scientist develops a model about climate change. The scientist makes this prediction in 2013. ‘By the year 2100 the average temperature at the Earth’s surface will rise by 1.5 °C.’ The same scientist changes the prediction in 2023. ‘By the year 2100 the average temperature at the Earth’s surface will rise by 2.5 °C.’ Suggest two reasons why the scientist changes the prediction. 1 2 [2] (b) The scientist plans an investigation to monitor air temperature during a period of one year. (i) The scientist uses a thermometer to measure air temperature. Look at the diagram showing part of the thermometer. °C 24 23 22 What is the temperature reading on the thermometer? °C [1] © UCLES 2024 S/S9/02 15 (ii) Tick () which plan gives the most appropriate evidence for the investigation. Measure the air temperature every day for one year. Measure the air temperature once a month for one year. Measure the air temperature once a week for one year. Measure the air temperature twice a day for one year. [1] © UCLES 2024 S/S9/02 [Turn over 16 13 Pierre investigates how a lack of magnesium affects plants. (a) The diagram shows the equipment he uses. plant cotton wool lid beaker control solution test solution control solution contains all the dissolved minerals a plant needs test solution contains all the dissolved minerals a plant needs but not magnesium Pierre measures the chlorophyll content in the leaves of both plants every day. (i) Pierre uses pure water to make the control solution and the test solution. Explain why Pierre uses pure water and not water from a tap. [1] © UCLES 2024 S/S9/02 17 (ii) Look at a graph of his results. 25 20 chlorophyll content of leaves in micrograms key control solution test solution 15 10 5 0 0 1 2 3 4 6 5 7 8 9 time in days Write down two conclusions about how magnesium affects the chlorophyll content of leaves. 1 2 [2] (b) Three solutions contain different percentages of minerals. solution A solution B solution C nitrates 2.0% nitrates 6.0% nitrates 4.0% magnesium 1.0% magnesium 0.2% magnesium 1.2% Which solution increases photosynthesis the most? Explain why. [1] © UCLES 2024 S/S9/02 [Turn over 18 14 Angelique makes an electrical circuit with a buzzer and a lamp. (a) Draw the standard electrical symbol for a buzzer. [1] (b) She uses an electrical component to control the brightness of the lamp. Draw the standard electrical symbol for this component. [1] © UCLES 2024 S/S9/02 19 15 Polar bears live in the Arctic. Their main habitat is sea ice. Polar bears use the sea ice when they are hunting for food. This sea ice is melting. Suggest how sea ice melting affects the polar bear population. Give two reasons for your answer. polar bear population reason 1 reason 2 [3] Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced annually and is available to download at https://lowersecondary.cambridgeinternational.org/ Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge. © UCLES 2024 S/S9/02 [Turn over © UCLES 2024 21 S/S9/02 calcium 40 38 Sr strontium 88 56 Ba barium 137 88 potassium 39 37 Rb rubidium 85 55 Cs caesium 133 87 actinoids lanthanoids – Ca K – actinoids 20 19 Ra 24 23 radium 89–103 magnesium sodium Fr 57–71 Mg Na francium 89 12 11 22 cerium 140 90 Th thorium 232 lanthanum 139 89 Ac actinium – 231 protactinium Pa 91 141 praseodymium Pr 59 58 Ce 57 – – dubnium Db 105 181 tantalum Ta 73 93 niobium Nb 41 51 vanadium V 23 Cr 24 238 uranium U 92 144 neodymium Nd 60 – seaborgium Sg 106 184 tungsten W 74 96 molybdenum Mo 42 52 chromium relative atomic mass rutherfordium Rf 104 178 hafnium Hf 72 91 zirconium Zr 40 48 titanium Ti La lanthanoids yttrium Y 39 45 scandium Sc 9 7 name atomic symbol Be beryllium Li lithium atomic number 4 3 Key 2 1 – neptunium Np 93 – promethium Pm 61 – bohrium Bh 107 186 rhenium Re 75 – technetium Tc 43 55 manganese Mn 25 – plutonium Pu 94 150 samarium Sm 62 – hassium Hs 108 190 osmium Os 76 101 ruthenium Ru 44 56 iron Fe 26 27 28 29 30 – americium Am 95 152 europium Eu 63 – meitnerium Mt 109 192 – curium Cm 96 157 gadolinium Gd 64 – darmstadtium Ds 110 195 platinum Pt Ir iridium 78 106 palladium Pd 46 59 nickel Ni 77 103 rhodium Rh 45 59 cobalt Co – berkelium Bk 97 159 terbium Tb 65 – roentgenium Rg 111 197 gold Au 79 108 silver Ag 47 64 copper Cu – californium Cf 98 163 dysprosium Dy 66 – copernicium Cn 112 201 mercury Hg 80 112 cadmium Cd 48 65 zinc Zn B C – einsteinium Es 99 165 holmium Ho 67 – nihonium Nh 113 204 thallium Tl 81 115 – fermium Fm 100 167 erbium Er 68 – flerovium Fl 114 207 lead Pb 82 119 tin Sn In indium 50 73 germanium Ge 32 28 silicon Si 14 12 carbon 49 70 gallium Ga 31 27 aluminium Al 13 11 boron 6 – mendelevium Md 101 169 thulium Tm 69 – moscovium Mc 115 209 bismuth Bi 83 122 antimony Sb 51 75 arsenic As 33 31 phosphorus P 15 14 nitrogen N 7 – nobelium No 102 173 ytterbium Yb 70 – livermorium Lv 116 – polonium Po 84 128 tellurium Te 52 79 selenium Se 34 32 sulfur S 16 16 oxygen O 8 – lawrencium Lr 103 175 lutetium Lu 71 – tennessine Ts 117 – astatine At 85 127 iodine I 53 80 bromine Br 35 35.5 chlorine Cl 17 19 fluorine F 9 – oganesson Og 118 – radon Rn 86 131 xenon Xe 54 84 krypton Kr 36 40 argon Ar 18 20 neon Ne 10 4 5 helium 8 1 7 hydrogen 6 2 5 He 4 H 3 1 Group The Periodic Table of Elements 20