Cambridge IGCSE Sciences - Co-ordinated (9-1) 0973 — 2022 May/June Paper 4 · Variant 1

This document has 36 pages. Any blank pages are indicated. [Turn over Cambridge IGCSE™(9–1) DC (CE/SG) 311737 © UCLES 2022 CO-ORDINATED SCIENCES 0973/41 Paper 4 Theory (Extended) May/June 2022 2 hours You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. ● Write your name, centre number and candidate number in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen or correction fluid. ● Do not write on any bar codes. ● You may use a calculator. ● You should show all your working and use appropriate units. INFORMATION ● The total mark for this paper is 120. ● The number of marks for each question or part question is shown in brackets [ ]. ● The Periodic Table is printed in the question paper. * 4 7 1 4 4 4 0 4 4 9 *

2 0973/41/M/J/22 © UCLES 2022 1 (a) Fig. 1.1 shows some specialised cells. side view top view A D E not to scale B C Fig. 1.1 (i) Identify the names of the cells labelled B and E in Fig. 1.1. B … E … [2] (ii) Explain how the structure of cell A is related to its function. … … … [2] (iii) Describe two ways in which cell D is adapted for transporting oxygen. 1 … 2 … [2] (b) Cell D is one of the main components of blood. State two other main components of blood. 1 … 2 … [2]

3 0973/41/M/J/22 © UCLES 2022 [Turn over (c) Blood vessels are adapted to their function. (i) Explain why arteries have a thick elastic wall. … … [1] (ii) Explain why veins have valves. … … [1] (iii) Explain why capillaries have very thin walls. … … [1] [Total: 11]

4 0973/41/M/J/22 © UCLES 2022 2 Ethene is a member of a family of hydrocarbons. Fig. 2.1 shows an ethene molecule. H C C H H H Fig. 2.1 (a) State the family of hydrocarbons that ethene is a member of. … [1] (b) Ethene is made from the larger molecules in petroleum. State the name of this process. … [1] (c) Poly(ethene) can be made from ethene. Poly(ethene) is a polymer. (i) State what is meant by a polymer. … … [2]

5 0973/41/M/J/22 © UCLES 2022 [Turn over (ii) Table 2.1 shows some information about polymers. Complete Table 2.1. Table 2.1 molecule used to make polymer name of polymer repeat unit of polymer H C C H H H poly(ethene) C C H H H H poly(chloroethene) C C Cl H H H F C C F F F poly(tetrafluoroethene) [2] (d) Ethene can be made into ethane. H C C H H H ethene H C C H H H H H ethane State the formula of the substance that ethene reacts with to make ethane. … [1] (e) Ethane is a saturated hydrocarbon. Describe what is meant by a saturated hydrocarbon. … … [1]

6 0973/41/M/J/22 © UCLES 2022 (f) Ethene undergoes an addition reaction with bromine. Fig. 2.2 shows the equation for the reaction. Complete the equation in Fig. 2.2 by drawing the structure of the compound formed. H C C H H H Br Br + …………………………… Fig. 2.2 [1] [Total: 9]

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8 0973/41/M/J/22 © UCLES 2022 3 Fig. 3.1 shows a forklift truck lifting a crate. crate weight Fig. 3.1 (a) The crate has a mass of 140 kg. (i) Calculate the weight of the crate. The gravitational field strength, g, is 10 N / kg. weight = … N [1] (ii) Calculate the work done on the crate when it is lifted through a height of 1.5 m. State the unit for your answer. work done = … unit … [3]

9 0973/41/M/J/22 © UCLES 2022 [Turn over (b) The forklift truck uses an electric motor to lift the crate. Fig. 3.2 shows the circuit that includes the electric motor. A V M 12 V motor Fig. 3.2 The voltmeter displays a reading of 0.50 V. (i) Show that the potential difference (p.d.) across the motor is 11.5 V. [1] (ii) The current in the circuit is 9.20 A. Calculate the resistance of the motor. resistance = … Ω [2] [Total: 7]

10 0973/41/M/J/22 © UCLES 2022 4 (a) Tay-Sachs disease is a genetic disorder that destroys nerve cells in the brain and spinal cord. The allele for Tay-Sachs disease is recessive t. The allele for unaffected by Tay-Sachs disease is dominant T. Fig. 4.1 is a pedigree diagram showing the inheritance of Tay-Sachs disease. A C D E G H J F KEY B unaffected female affected female unaffected male affected male Fig. 4.1 (i) State the number of males in Fig. 4.1 that are unaffected by Tay-Sachs disease. … [1] (ii) Complete the sentences to explain the genotypes of some of the people in Fig. 4.1. Person E and person F are … by Tay-Sachs disease. Person E and person F both have the genotype … . Person G has Tay-Sachs disease. They have the genotype … . Person G will have inherited one … allele from each parent. [4] (iii) State the probability of two parents with the genotypes TT having a child with Tay-Sachs disease. … [1]

11 0973/41/M/J/22 © UCLES 2022 [Turn over (b) Growth of offspring involves mitosis. The box on the left contains the term mitosis. The boxes on the right contain some sentence endings. Draw three lines from the word mitosis to the boxes on the right to make three correct sentences about mitosis. Mitosis occurs after exact duplication of chromosomes. is involved in the production of gametes. is reduction division. produces cells with diploid nuclei. produces nuclei with paired chromosomes. produces genetically different cells. [3] (c) State the number of chromosomes in a human diploid cell. … [1] (d) State the term given to a change in a gene or chromosome. … [1] [Total: 11]

12 0973/41/M/J/22 © UCLES 2022 5 In an experiment, a student adds an alkali to an acid. Fig. 5.1 shows the experiment. acid alkali Fig. 5.1 (a) The student slowly adds the alkali to the acid. (i) Describe how the pH of the acid changes as the alkali is added. … [1] (ii) Complete the word equation to show the type of substance made in the reaction. acid + alkali …………………. + water [1] (iii) Sulfuric acid, H2SO4, is an acid. Potassium hydroxide, KOH, is an alkali. Construct the balanced symbol equation for the reaction of sulfuric acid with potassium hydroxide. … + … … + … [2] (iv) State the formula of the ion which is present in solutions of all acids. … [1]

13 0973/41/M/J/22 © UCLES 2022 [Turn over (b) Ammonium sulfate, (NH4)2SO4, is made by reacting an acid with an alkali. Calculate the relative formula mass, Mr , of ammonium sulfate. [Ar: H, 1; N, 14; O, 16; S, 32] relative formula mass = … [1] (c) The alkali used to make ammonium sulfate is ammonia, NH3. Ammonia is made by the Haber process. Nitrogen, N2, and hydrogen, H2, are the starting materials. Look at the equation for the reaction. N2 + 3H2 2NH3 (i) Describe the Haber process. You should include: • the sources of nitrogen and hydrogen gas • the conditions used. … … … … [3]

14 0973/41/M/J/22 © UCLES 2022 (ii) Ammonia, NH3, reacts with nitric acid, HNO3. Ammonium nitrate, NH4NO3, is made. Look at the equation for the reaction. NH3 + HNO3 NH4NO3 Calculate the mass of ammonium nitrate made from 51 kg of ammonia. Show your working. [Ar: H, 1; N, 14; O, 16] mass = … kg [2] [Total: 11]

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16 0973/41/M/J/22 © UCLES 2022 6 Fig. 6.1 shows a tidal power station which uses tidal energy to generate electricity. The moving water turns a turbine which is connected to a generator. warning lamp turbine direction of water flow sea level generator Fig. 6.1 (a) (i) State the source of the energy for the tides. … [1] (ii) Each kilogram of water has 1.62 J of kinetic energy. Calculate the speed of the water flow. speed = … m / s [2]

17 0973/41/M/J/22 © UCLES 2022 [Turn over (b) Fig. 6.2 shows a simple a.c. generator. S X N voltage output permanent magnets Fig. 6.2 (i) On Fig. 6.2, draw an arrow to show the direction of the magnetic field between the permanent magnets. [1] (ii) State the name of the components labelled X and describe their use. name … use … … [2] (iii) On Fig. 6.3, sketch a graph of voltage output against time for a simple a.c. generator operating at a constant speed. voltage output time Fig. 6.3 [2]

18 0973/41/M/J/22 © UCLES 2022 (c) The tidal power station uses a warning lamp to warn passing boats of its location. The lamp emits light with a wavelength of 4.0 × 10–7 m. Calculate the frequency of the light. frequency = … Hz [3] [Total: 11]

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20 0973/41/M/J/22 © UCLES 2022 7 (a) Fig. 7.1 is a photograph of a wind-pollinated flower. A Fig. 7.1 Identify part A in Fig. 7.1. … [1] (b) Describe one way the pollen and petals of insect-pollinated flowers are different from wind- pollinated flowers. pollen … petals … [2] (c) State where fertilisation occurs in a plant. … [1] (d) Many plants are able to reproduce sexually and asexually. Describe the disadvantages to a plant in the wild of reproducing asexually. … … … [2] (e) State two requirements for germination of plant seeds. 1 … 2 … [2] [Total: 8]

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22 0973/41/M/J/22 © UCLES 2022 8 Table 8.1 gives some information about atoms. Table 8.1 atom proton number nucleon number electronic structure sodium 11 23 2.8.1 fluorine 9 19 2.7 chlorine 17 35 2.8.7 chlorine 17 37 2.8.7 argon … 40 2.8.8 magnesium 12 24 … (a) Complete Table 8.1. [2] (b) Chlorine appears twice in Table 8.1. Each of the atoms is an isotope of chlorine. (i) Explain what is meant by the word isotope. … … … [2] (ii) The two isotopes of chlorine have the same chemical properties. Explain why. … … [1] (c) Argon is a noble gas. Explain why argon is very unreactive. Use ideas about electronic structure. … … [1]

23 0973/41/M/J/22 © UCLES 2022 [Turn over (d) Sodium is a metal. Describe the bonding in a metal. You may draw a diagram to help your answer. … … … [2] (e) Magnesium chloride contains the ions Mg2+ and Cl –. Determine the formula of magnesium chloride. formula = … [1] (f) Fluorine, F2, reacts with sodium chloride, NaCl. Construct the balanced symbol equation for the reaction. … [2] [Total: 11]

24 0973/41/M/J/22 © UCLES 2022 9 A student investigates the motion of smoke particles in air using a microscope. The student shines a bright light on a transparent box containing a mixture of smoke and air and observes the smoke particles as bright dots of light. (a) The student observes that the smoke particles move in straight lines between random changes of direction. Fig. 9.1 shows the observed path of one smoke particle. smoke particle Fig. 9.1 The motion shown in Fig. 9.1 is known as Brownian motion. Describe what causes the motion of the smoke particles shown in Fig. 9.1. … … … … [2]

25 0973/41/M/J/22 © UCLES 2022 [Turn over (b) The microscope uses a filament lamp to illuminate the smoke particles. Fig. 9.2 shows how current varies with potential difference (p.d.) for the filament lamp. potential difference current Fig. 9.2 Use the shape of the graph in Fig. 9.2 to describe and explain what happens to the resistance of the filament lamp as the potential difference is increased. … … … … … … [3]

26 0973/41/M/J/22 © UCLES 2022 (c) The microscope uses a thin converging lens to produce an image. Fig. 9.3 shows a thin converging lens. F F = principal focus F object Fig. 9.3 (i) Draw a ray diagram on Fig. 9.3 to show the formation of a real image. Label the image with the word image. [3]

27 0973/41/M/J/22 © UCLES 2022 [Turn over (ii) Fig. 9.4 shows a single ray of light entering a thin glass block. 28° 50° Fig. 9.4 Calculate the refractive index of the thin glass block. refractive index = … [2] [Total: 10]

28 0973/41/M/J/22 © UCLES 2022 10 The control of blood glucose concentration is an involuntary action by the body. (a) Place ticks (3) in the boxes to show two other involuntary actions. coughing cycling reading sneezing talking [2] (b) State the characteristic of living things that is defined as the ability to respond to a stimulus. … [1] (c) Fig. 10.1 is a graph that shows the blood glucose concentration after eating a meal. blood glucose concentration mmol / dm3 10 9 8 7 6 5 80 70 60 50 time / minutes 40 30 20 10 0 0 Fig. 10.1 (i) Calculate the length of time it takes for the blood glucose concentration to return to its starting concentration from its maximum. … minutes [1] (ii) Explain the results between 20–30 minutes in Fig. 10.1. … … … … … [3]

29 0973/41/M/J/22 © UCLES 2022 [Turn over (iii) State the type of response shown by the control of blood glucose concentration. … [1] (d) State the names of two hormones that can increase the blood glucose concentration. 1 … 2 … [2] [Total: 10]

30 0973/41/M/J/22 © UCLES 2022 11 A student investigates indigestion tablets. Indigestion tablets neutralise acids. The student measures 50 cm3 of dilute hydrochloric acid into a beaker. He adds an indigestion tablet to the acid. Fig. 11.1 shows the student’s experiment. beaker indigestion tablet 50 cm3 dilute hydrochloric acid Fig. 11.1 The student measures the time the tablet takes to react completely. He repeats the experiment but makes one change each time. Table 11.1 shows his results. Table 11.1 experiment volume of acid / cm3 concentration of acid temperature of acid / °C time for tablet to react / s 1 50 dilute 20 131 2 50 concentrated 20 66 3 100 concentrated 20 66 4 50 concentrated 30 32 (a) The volume of acid does not affect the rate of reaction. State which two experiments show this. … and … [1]

31 0973/41/M/J/22 © UCLES 2022 [Turn over (b) Increasing the temperature of the acid affects the rate of reaction. Increasing the concentration of the acid also affects the rate of reaction. For each factor (temperature and concentration): • describe how the rate of reaction changes • explain why the rate of reaction changes, using ideas about particles. temperature how the rate of reaction changes … … because … … … concentration how the rate of reaction changes … … because … … … [4] (c) In experiment 1, the student uses dilute hydrochloric acid with a concentration of 0.1 mol / dm3. Calculate the concentration of the dilute hydrochloric acid in g / dm3. [Ar: H, 1; Cl, 35.5] answer = … g / dm3 [1] (d) The reaction between the indigestion tablet and the acid is an exothermic reaction. Explain why. Use ideas about bond breaking and bond making. … … … … [3] [Total: 9]

32 0973/41/M/J/22 © UCLES 2022 12 A rocket is used to launch satellites into Earth’s orbit. (a) Fig. 12.1 shows the forces acting on a rocket as it is launched. thrust = 15.7 × 106 N weight = 7.8 × 106 N Fig. 12.1 (i) Calculate the resultant force acting on the rocket as it is launched. resultant force = … N [1] (ii) Describe the motion of the rocket as it is launched. … … … … [2] (iii) Suggest a reason why the weight decreases as the rocket travels further away from Earth. … … [1]

33 0973/41/M/J/22 © UCLES 2022 [Turn over (b) Fig. 12.2 shows a satellite in orbit around the Earth. The satellite orbits at a height of 2000 km above the surface of the Earth. The satellite takes 125 minutes to complete one orbit. The satellite travels at an average speed of 7.1 km / s. Fig. 12.2 Calculate the radius of the Earth. radius of the Earth = … km [4]

34 0973/41/M/J/22 © UCLES 2022 (c) When in orbit, satellites are subject to ionising radiation coming from space. This radiation includes α-particles, β-particles and γ-rays. (i) State and explain which forms of ionising radiation will be deflected by the Earth’s magnetic field. forms of radiation … explanation … … … [2] (ii) A β-particle is emitted when the radioactive isotope iodine-131 decays into an isotope of xenon. Use the correct nuclide notation to complete the decay equation for iodine-131. 131 53 I … … Xe + … … β [2] [Total: 12]

35 0973/41/M/J/22 © UCLES 2022 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 for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. 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. BLANK PAGE

36 0973/41/M/J/22 © UCLES 2022 Group The Periodic Table of Elements 1 H hydrogen 1 2 He helium 4 I II III IV V VI VII VIII 3 Li lithium 7 4 Be beryllium 9 atomic number atomic symbol Key name relative atomic mass 11 Na sodium 23 12 Mg magnesium 24 19 K potassium 39 20 Ca calcium 40 37 Rb rubidium 85 38 Sr strontium 88 55 Cs caesium 133 56 Ba barium 137 87 Fr francium – 88 Ra radium – 5 B boron 11 13 Al aluminium 27 31 Ga gallium 70 49 In indium 115 81 Tl thallium 204 6 C carbon 12 14 Si silicon 28 32 Ge germanium 73 50 Sn tin 119 82 Pb lead 207 22 Ti titanium 48 40 Zr zirconium 91 72 Hf hafnium 178 104 Rf rutherfordium – 23 V vanadium 51 41 Nb niobium 93 73 Ta tantalum 181 105 Db dubnium – 24 Cr chromium 52 42 Mo molybdenum 96 74 W tungsten 184 106 Sg seaborgium – 25 Mn manganese 55 43 Tc technetium – 75 Re rhenium 186 107 Bh bohrium – 26 Fe iron 56 44 Ru ruthenium 101 76 Os osmium 190 108 Hs hassium – 27 Co cobalt 59 45 Rh rhodium 103 77 Ir iridium 192 109 Mt meitnerium – 28 Ni nickel 59 46 Pd palladium 106 78 Pt platinum 195 110 Ds darmstadtium – 29 Cu copper 64 47 Ag silver 108 79 Au gold 197 111 Rg roentgenium – 30 Zn zinc 65 48 Cd cadmium 112 80 Hg mercury 201 112 Cn copernicium – 114 Fl flerovium – 116 Lv livermorium – 7 N nitrogen 14 15 P phosphorus 31 33 As arsenic 75 51 Sb antimony 122 83 Bi bismuth 209 8 O oxygen 16 16 S sulfur 32 34 Se selenium 79 52 Te tellurium 128 84 Po polonium – 9 F fluorine 19 17 Cl chlorine 35.5 35 Br bromine 80 53 I iodine 127 85 At astatine – 10 Ne neon 20 18 Ar argon 40 36 Kr krypton 84 54 Xe xenon 131 86 Rn radon – 21 Sc scandium 45 39 Y yttrium 89 57–71 lanthanoids 89–103 actinoids 57 La lanthanum 139 89 Ac lanthanoids actinoids The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.). actinium – 58 Ce cerium 140 90 Th thorium 232 59 Pr praseodymium 141 91 Pa protactinium 231 60 Nd neodymium 144 92 U uranium 238 61 Pm promethium – 93 Np neptunium – 62 Sm samarium 150 94 Pu plutonium – 63 Eu europium 152 95 Am americium – 64 Gd gadolinium 157 96 Cm curium – 65 Tb terbium 159 97 Bk berkelium – 66 Dy dysprosium 163 98 Cf californium – 67 Ho holmium 165 99 Es einsteinium – 68 Er erbium 167 100 Fm fermium – 69 Tm thulium 169 101 Md mendelevium – 70 Yb ytterbium 173 102 No nobelium – 71 Lu lutetium 175 103 Lr lawrencium –

This document consists of 12 printed pages. © UCLES 2022 [Turn over Cambridge IGCSE™ (9–1) CO-ORDINATED SCIENCES (9–1) 0973/41 Paper 4 Theory (Extended) May/June 2022 MARK SCHEME Maximum Mark: 120 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the May/June 2022 series for most Cambridge IGCSE, Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level components.

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 2 of 12 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with:  the specific content of the mark scheme or the generic level descriptors for the question  the specific skills defined in the mark scheme or in the generic level descriptors for the question  the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively:  marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate  marks are awarded when candidates clearly demonstrate what they know and can do  marks are not deducted for errors  marks are not deducted for omissions  answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors.

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 3 of 12 GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind. Science-Specific Marking Principles 1 Examiners should consider the context and scientific use of any keywords when awarding marks. Although keywords may be present, marks should not be awarded if the keywords are used incorrectly. 2 The examiner should not choose between contradictory statements given in the same question part, and credit should not be awarded for any correct statement that is contradicted within the same question part. Wrong science that is irrelevant to the question should be ignored. 3 Although spellings do not have to be correct, spellings of syllabus terms must allow for clear and unambiguous separation from other syllabus terms with which they may be confused (e.g. ethane / ethene, glucagon / glycogen, refraction / reflection). 4 The error carried forward (ecf) principle should be applied, where appropriate. If an incorrect answer is subsequently used in a scientifically correct way, the candidate should be awarded these subsequent marking points. Further guidance will be included in the mark scheme where necessary and any exceptions to this general principle will be noted. 5 ‘List rule’ guidance For questions that require n responses (e.g. State two reasons …):  The response should be read as continuous prose, even when numbered answer spaces are provided.  Any response marked ignore in the mark scheme should not count towards n.  Incorrect responses should not be awarded credit but will still count towards n.  Read the entire response to check for any responses that contradict those that would otherwise be credited. Credit should not be awarded for any responses that are contradicted within the rest of the response. Where two responses contradict one another, this should be treated as a single incorrect response.  Non-contradictory responses after the first n responses may be ignored even if they include incorrect science.

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 4 of 12 6 Calculation specific guidance Correct answers to calculations should be given full credit even if there is no working or incorrect working, unless the question states ‘show your working’. For questions in which the number of significant figures required is not stated, credit should be awarded for correct answers when rounded by the examiner to the number of significant figures given in the mark scheme. This may not apply to measured values. For answers given in standard form (e.g. a  10n) in which the convention of restricting the value of the coefficient (a) to a value between 1 and 10 is not followed, credit may still be awarded if the answer can be converted to the answer given in the mark scheme. Unless a separate mark is given for a unit, a missing or incorrect unit will normally mean that the final calculation mark is not awarded. Exceptions to this general principle will be noted in the mark scheme. 7 Guidance for chemical equations Multiples / fractions of coefficients used in chemical equations are acceptable unless stated otherwise in the mark scheme. State symbols given in an equation should be ignored unless asked for in the question or stated otherwise in the mark scheme.

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 5 of 12 Question Answer Marks 1(a)(i) B – root hair (cell) ; E – sperm (cell) ; 2 1(a)(ii) presence of cilia ; to remove mucus (from the, trachea / bronchi / gas exchange system) ; 2 1(a)(iii) any two from: biconcave shape ; contain haemoglobin ; no nucleus ; 2 1(b) any two from: white blood cells ; platelets ; plasma ; 2 1(c)(i) to prevent bursting / withstand high pressure (of blood) ; 1 1(c)(ii) to prevent backflow of blood ; 1 1(c)(iii) so there is a short diffusion distance / AW ; 1 Question Answer Marks 2(a) alkenes ; 1 2(b) cracking ; 1 2(c)(i) long chain (molecule) / owtte ; formed from (many), small units / molecules / monomers ; 2

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 6 of 12 Question Answer Marks 2(c)(ii) ; ; 2 2(d) H2 ; 1 2(e) (molecules contain) only single bonds ; 1 2(f) ; 1 Question Answer Marks 3(a)(i) (W = mg / 140  10) = 1400 (N) ; 1 3(a)(ii) (W =) fxd / 1400  1.5 ; 2100 ; Joules / J ; 3 3(b)(i) 12 – 0.50 (= 11.5) ; 1 3(b)(ii) (R =) V / I or 11.5 / 9.20 ; 1.25 () ; 2

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 7 of 12 Question Answer Marks 4(a)(i) 4 ; 1 4(a)(ii) unaffected ; Tt ; tt ; recessive ; 4 4(a)(iii) 0(%) ; 1 4(b) Mitosis joined to: occurs after exact duplication of chromosomes ; produces cells with diploid nuclei ; produces nuclei with paired chromosomes ; 3 4(c) 46 / 23 pairs ; 1 4(d) mutation ; 1 Question Answer Marks 5(a)(i) increases / owtte ; 1 5(a)(ii) salt ; 1 5(a)(iii) H2SO4 + 2KOH  K2SO4 + 2H2O ;; 2 5(a)(iv) H+ ; 1 5(b) 132 ; 1 5(c)(i) source of nitrogen is air and source of hydrogen is natural gas / methane ; plus any two from: (pressure of) 200 atmospheres ; (temperature of) 450 °C ; (iron) catalyst ; 3

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 8 of 12 Question Answer Marks 5(c)(ii) relative formular mass of NH3 =17 and of NH4NO3 = 80 ; 80 51 17  = 240 (kg) ; 2 Question Answer Marks 6(a)(i) the moon ; 1 6(a)(ii) (v =) √(2KE / m) / √(2  1.62) in any form ; 1.8 (m / s) ; 2 6(b)(i) arrow drawn N to S ; 1 6(b)(ii) slip ring(s) ; maintains electrical contact with brushes or circuit / prevents wires from becoming tangled / allows production of an ac output ; 2 6(b)(iii) sinusoidal wave ; constant period and amplitude ; 2 6(c) (v =) 3  108 (m / s) ; (f =) v /  or 3  108 / 4.0  10–7 ; 7.5  1014 (Hz) ; 3 Question Answer Marks 7(a) stigma ; 1 7(b) (pollen is) larger / heavier / stickier / less numerous ; (petals are) larger / brightly coloured / possess guidelines / scented ; 2 7(c) ovule / ovary ; 1

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 9 of 12 Question Answer Marks 7(d) no (genetic) variation ; a disease more likely to wipe out whole population / unable to adapt to changes in the environment ; 2 7(e) any two from: oxygen ; water ; suitable temperature ; 2 Question Answer Marks 8(a) argon – proton number = 18 ; magnesium – electronic configuration = 2.8.2 ; 2 8(b)(i) same proton or atomic number / same number of protons ; (but) different nucleon number / different number of neutrons ; 2 8(b)(ii) (both have) same numbers of electrons in the outer shell / same electronic structure ; 1 8(c) (argon has) a full outer shell (of electrons) / AW ; 1 8(d) (lattice of) positive ions ; in a ‘sea of electrons’ ; 2 8(e) MgCl2 ; 1 8(f) F2 + 2NaCl  Cl2 + 2NaF ;; 2 Question Answer Marks 9(a) reference to collisions ; with, light fast-moving particles / air particles / molecules ; 2 9(b) initially pd is (directly) proportional to current / resistance is constant ; (as pd is increased) resistance increases shown by decreasing gradient ; as the filament heats up ; 3

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 10 of 12 Question Answer Marks 9(c)(i) ;; Image drawn and labelled ; 3 9(c)(ii) (n =) sin i / sin r / sin 50 / sin 28 ; 1.63 ; 2 Question Answer Marks 10(a) coughing ticked ; sneezing ticked ; 2 10(b) sensitivity ; 1 10(c)(i) 60 (minutes) ; 1 F = principal focus

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 11 of 12 Question Answer Marks 10(c)(ii) any three from: increase in blood glucose concentration is detected by pancreas ; insulin released ; glucose converted to glycogen ; glycogen stored in liver ; Max 3 3 10(c)(iii) negative feedback / homeostasis ; 1 10(d) glucagon ; adrenaline ; AVP ; 2 Question Answer Marks 11(a) 2 and 3 ; 1 11(b) temperature (as the temperature increases, the rate of reaction) increases / owtte ; particles move faster / particles have more (kinetic) energy / more particles have, activation energy / sufficient energy, to react ; concentration (as the concentration increases, the rate of reaction) increases / owtte ; more particles per unit volume / less space between particles ; 4 11(c) (0.1  36.5) = 3.65 (g / dm3) ; 1 11(d) bond breaking is endothermic / absorbs energy owtte ; bond making is exothermic / releases energy owtte ; more energy is given out (in bond making) than is taken in (in bond breaking) ; 3

0973/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 12 of 12 Question Answer Marks 12(a)(i) 7.9  106 (N) ; 1 12(a)(ii) accelerates ; upwards; 2 12(a)(iii) gravitational field strength decreases / rocket uses up fuel ; 1 12(b) (125 mins =) 7500 (s) or 125  60 ; (d =) vxt / 7.1  7500 or 53 250 (km) ; (rorbit =) d / 2 / 53 250 / (2  3.14) or 8475 (km) ; (rearth =) 8475 – 2000 or rorbit – 2000 = 6475 (km) ; 4 12(c)(i) alpha AND beta ; they are charged / gamma is not charged ; 2 12(c)(ii) 131 131 0 53 54 1 Xe     I ;; 2