Science Stage 7 Paper 1 2023 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 [ ]. 3144_01_7RP © UCLES 2023 2 1 This question is about cells. (a) Draw a straight line to match each part of a cell to its correct function. part of a cell function controls the movement of substances into and out of the cell cell membrane contains genetic information and controls what happens inside the cell cytoplasm jelly-like substance, where chemical reactions happen mitochondria where most respiration reactions happen [2] (b) Look at the diagram of a plant palisade cell. nucleus vacuole cell wall chloroplasts cell membrane Describe how the palisade cell is specialised to allow it to photosynthesise. [2] © UCLES 2023 3144_01 3 (c) Euglena is a single-celled organism. Look at the diagram of an euglena. flagellum eye spot cytoplasm nucleus chloroplast cell membrane Explain why euglena is difficult to classify as either a plant cell or an animal cell. [1] © UCLES 2023 3144_01 [Turn over 4 2 This question is about materials. Draw a straight line to match each material to its correct description. material description a pure substance containing the same type of atom alloy a pure substance containing different types of atoms bonded together compound a mixture containing two different types of metal atoms element an impure substance containing the same type of atom a substance containing atoms that are free to move [3] © UCLES 2023 3144_01 5 3 Sound is reflected by hard surfaces. (a) What is the name given to a reflected sound? [1] (b) A ship is using sound to calculate the distance to the seabed. The ship produces a sound. The sound travels to the seabed and is reflected back to the ship. sound reflection seabed In water, sound travels a distance of 1500 m in one second. The reflected sound is detected after 4 seconds. Calculate the distance from the bottom of the ship to the seabed. m © UCLES 2023 3144_01 [2] [Turn over 6 4 The solid outer layer of the Earth is made up of large tectonic plates. Look at the diagram showing a model of what happens when two tectonic plates meet. (a) Write down the name of the two parts of the Earth that form this solid outer layer. 1 2 [2] (b) Write down three different events that happen near the boundaries of tectonic plates. 1 2 3 [3] (c) Describe the strengths and limitations of this model about the movement of tectonic plates. [2] © UCLES 2023 3144_01 7 5 The incomplete dichotomous key shows different features of vertebrates. Write words from the list in the boxes to complete the key. amphibian bird fish mammal reptile vertebrate fur no fur ....................................... feathers no feathers ....................................... dry scaly skin moist skin ....................................... scales ....................................... no scales ....................................... [3] © UCLES 2023 3144_01 [Turn over 8 6 Chen tests some chemicals with Universal Indicator. His results are shown on a pH chart. 1 2 lemon juice 3 4 5 6 7 8 vinegar 9 10 11 12 13 14 bath salts floor paint cleaner stripper Use the pH chart to answer the questions. (a) Write down the pH of vinegar. [1] (b) Paint stripper is tested with Universal Indicator. Write down the colour of the Universal Indicator after the test. [1] (c) Pure water is neutral. Write down the pH of a neutral solution. [1] (d) Which chemical in the pH chart is the most acidic? [1] © UCLES 2023 3144_01 9 7 Energy is transferred from one form into another. (a) The diagram shows a television. Complete the energy transfer for the television. .......................................... energy .......................................... energy .......................................... energy .......................................... energy [1] (b) A car transfers chemical energy in gasoline (petrol) into thermal energy, sound energy and kinetic energy only. The car transfers 100 J of chemical energy into 70 J of thermal energy and 10 J of sound energy. (i) Calculate how much chemical energy is transferred into kinetic energy. J [1] (ii) Describe what happens to the sound and thermal energy. [1] © UCLES 2023 3144_01 [Turn over 10 8 Look at the table showing the percentage by volume of different gases in clean, dry air. gas percentage by volume 78 ……………………. oxygen ……………………. Complete the table with the name of the missing gas and the missing percentage. [2] 9 Donkeys mate and produce new generations of donkeys. Horses mate and produce new generations of horses. A male donkey and a female horse mate and produce a mule. Mules mate but do not produce offspring. Tick (✓) to show which of the animals are species. donkey horse mule Explain your answer. [2] © UCLES 2023 3144_01 11 10 Safia investigates chemical reactions. (a) Safia adds two colourless solutions together. She sees that a white solid is made. Name the process that happens when this white solid is made from the two solutions. Circle the correct answer. alloying decomposition melting precipitation [1] (b) Safia now adds sodium hydroxide solution to dilute hydrochloric acid. Sodium hydroxide solution is an alkali. What happens to the pH of the dilute hydrochloric acid as the sodium hydroxide solution is added? Explain your answer. [2] © UCLES 2023 3144_01 [Turn over 12 11 Blessy collects some information about gravity on different planets in the Solar System. (a) What is gravity? [2] (b) Look at the information Blessy collects. planet relative mass (Earth = 1) relative gravity (Earth = 1) Mercury 0.06 0.4 Mars 0.1 0.4 Venus 0.8 0.9 Earth 1 1.0 Uranus 15 0.9 Neptune 17 1.1 Saturn 95 0.9 Jupiter 318 2.4 (i) Write down the name of the planet that has the greatest gravity. [1] (ii) Write down a conclusion about the relationship between mass of planet and gravity. Include information from the table in your answer. [2] © UCLES 2023 3144_01 13 12 A research chemist investigates some compounds. She wants to dissolve them in water and test the pH of the solution. Look at the table showing the compounds she uses and their hazard symbols. compound hazard symbol description of hazard sulfuric acid ………………………..………… potassium nitrate hazardous to the environment ethanol ………………………..………… mercury nitrate ………………………..………… Complete the table to describe the hazard for each compound. One has been done for you. [3] © UCLES 2023 3144_01 [Turn over 14 13 Oliver investigates electricity. He makes an electrical circuit using different materials to complete the circuit. lamp + – material cell He records his observations. Look at his results. material does the lamp light? iron yes steel yes plastic no wood no rubber no graphite yes aluminium yes (a) Write down all the materials in the table that conduct electricity. [1] (b) Write down the name of the particles that flow through conductors. [1] (c) Write down the word used to describe materials that do not conduct electricity. [1] © UCLES 2023 3144_01 15 14 Look at the incomplete food web. hawk snake rabbit lizard mouse grasshopper grass The grasshopper feeds on grass. The lizard feeds on the grasshopper. The hawk feeds on the snake, the rabbit, the grasshopper and the lizard. (a) Draw arrows to complete the food web. [2] (b) The hawk is a top predator and is not eaten by other predators. Write down two ways that energy from the hawk is returned to the grass. 1 2 [2] 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 2023 3144_01 [Turn over © UCLES 2023 21 22 3144_01 40 38 Sr strontium 88 56 Ba barium 137 88 39 37 Rb rubidium 85 55 Cs caesium 133 87 actinoids lanthanoids – actinoids calcium potassium – 89–103 Ca K Ra 57–71 20 19 radium 89 24 23 Fr 104 39 magnesium sodium francium 178 45 Mg Na 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 hafnium Hf 72 91 zirconium Zr 40 48 titanium La lanthanoids yttrium Y scandium Ti 12 11 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 49 70 gallium Ga 31 27 aluminium Si 14 13 Al 12 carbon 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 16
