Cambridge IGCSE Science - Combined 0653 — 2018 May/June Paper 2 · Variant 3
0653/23/M/J/18 · 40 questions · 40 marks · ≈45 min
The question paper and its mark scheme, free to read here and free to download. This is Cambridge’s own paper, exactly as it was sat.
Question paper16 pages
Mark scheme3 pages
Answers below. Sit the paper first if you are practising.
Questions as text
Q1 · Which structure found in plant cells traps light energy for photosynthesis?
1 Which structure found in plant cells traps light energy for photosynthesis? A cell wall B chloroplast C nucleus D vacuole
Mark scheme: B
Q2 · Amylase is an enzyme that digests starch
2 Amylase is an enzyme that digests starch. Identical mixtures of starch and amylase are kept at different temperatures. The percentage of starch digested in 20 minutes is recorded. The results are shown in the graph. 100 percentage of starch digested 50 in 20 minutes 0 0 10 20 30 40 50 60 70 temperature / °C The mixtures that were kept at 0 °C and 70 °C are then kept at a temperature of 40 °C for one hour. What are the results after this hour? percentage of starch digested sample originally sample originally kept at 0 °C kept at 70 °C A 0 0 B 0 100 C 100 0 D 100 100
Mark scheme: C
Q3 · Which substance is broken down to produce lactic acid during the manufacture of yoghurt?
3 Which substance is broken down to produce lactic acid during the manufacture of yoghurt? A glucose B lactose C protein D starch
Mark scheme: B
Q4 · Which two chemical substances are required for photosynthesis?
4 Which two chemical substances are required for photosynthesis? A carbon dioxide and glucose B glucose and oxygen C oxygen and water D water and carbon dioxide
Mark scheme: D
Q5 · Aperson eats a diet high in carbohydrate and fat and low in fibre
5 Aperson eats a diet high in carbohydrate and fat and low in fibre. What might be the long-term consequences of this diet? constipation obesity starvation A x Jv J B Jv x J Cc x x x D Jv Jv x
Mark scheme: D
Q6 · The diagram shows a section through the human heart
6 The diagram shows a section through the human heart. valve 4 valve 3 valve 2 valve 1 What happens to the valves as blood is being pumped to the lungs? valve 1 valve 2 valve 3 valve 4 A closed closed open closed B closed closed open open C open open closed closed D open open closed open
Mark scheme: B
Q7 · The diagram shows cross-sections of two different blood vessels
7 The diagram shows cross-sections of two different blood vessels. P Q What type of blood vessel is Q and what is the relative blood pressure in Q compared with P? relative blood blood vessel Q pressure in Q A artery higher B artery lower C vein higher D vein lower
Mark scheme: D
Q8 · What is the maximum number of carbon dioxide molecules produced when four glucose…
8 What is the maximum number of carbon dioxide molecules produced when four glucose molecules are used in aerobic respiration? A 6 B 12 C 24 D 48
Mark scheme: C
Q9 · What are the functions of the cilia and mucus in the gas exchange system?
9 What are the functions of the cilia and mucus in the gas exchange system? cilia mucus A make mucus trap pathogens B make mucus move cilia C move mucus trap pathogens D move mucus move cilia
Mark scheme: C
Q10 · The diagram shows a seedling with its root horizontal
10 The diagram shows a seedling with its root horizontal. Y root X Gravity is the stimulus acting on the seedling. Where will the greatest concentration of auxin be found in the root and what effect will this have on the rate of cell elongation? greatest effect of auxin concentration on rate of cell of auxin elongation A X decreases B X increases C Y decreases D Y increases
Mark scheme: A
Q11 · The table shows some features of flowers
11 The table shows some features of flowers. Which features are typical of wind-pollinated flowers? petals position of anther nectaries A large inside flower absent B large outside flower present C small inside flower present D small outside flower absent
Mark scheme: D
Q12 · What is a disadvantage of breast-feeding compared with bottle-feeding using formula milk?
12 What is a disadvantage of breast-feeding compared with bottle-feeding using formula milk? A difficult to measure the amount of milk given B milk contains antibodies C milk is always immediately available D milk is at the optimum temperature
Mark scheme: A
Q13 · The diagram shows how energy flows through a food chain
13 The diagram shows how energy flows through a food chain. Sun Y Y Y X Z Z producer herbivore carnivore What are the main energy transfers shown by arrows X, Y and Z? X Y Z A chemical → chemical chemical → heat chemical → light B chemical → chemical chemical → light chemical → light C light → chemical chemical → heat chemical → chemical D light → chemical chemical → light chemical → chemical
Mark scheme: C
Q14 · The diagrams represent different substances
14 The diagrams represent different substances. P Q R S T Which row describes the substances? only separate mixture of atoms only molecules atoms and molecules A P Q S B Q T R C T P R D T Q P
Mark scheme: A
Q15 · A mixture of salt water and sand is filtered
15 A mixture of salt water and sand is filtered. Which statement is correct? A The salt and the sand are trapped by the filter paper. B The salt is dissolved in the water and passes through the filter paper. C The sand is insoluble in water and passes through the filter paper. D The sand is trapped by the filter paper and pure water is obtained.
Mark scheme: B
Q16 · Which process is not a chemical change?
16 Which process is not a chemical change? A the electrolysis of molten lead bromide B the fractional distillation of petroleum C the oxidation of copper D the rusting of iron
Mark scheme: B
Q17 · Chromium oxide contains chromium ions, Cr3+, and oxide ions, O2–
17 Chromium oxide contains chromium ions, Cr3+, and oxide ions, O2–. What is the formula of chromium oxide? A CrO B CrO2 C Cr2O3 D Cr3O2
Mark scheme: C
Q18 · The diagram shows apparatus for electrolysis
18 The diagram shows apparatus for electrolysis. Only one label is correct. electrode + – cathode anode electrolyte Which label on the diagram is correct? A anode B cathode C electrode D electrolyte
Mark scheme: D
Q19 · Molten calcium chloride is electrolysed
19 Molten calcium chloride is electrolysed. What happens at the negative electrode? A Calcium atoms lose electrons to form calcium ions. B Calcium ions gain electrons to form calcium atoms. C Chloride ions lose electrons to form chlorine molecules. D Chlorine molecules gain electrons to form chloride ions.
Mark scheme: B
Q20 · Which change must take place in an endothermic reaction?
20 Which change must take place in an endothermic reaction? A Bubbles of gas are released. B The mass decreases. C The temperature decreases. D The temperature increases.
Mark scheme: C
Q21 · Dilute hydrochloric acid is reacted with calcium carbonate at 20 °C
21 Dilute hydrochloric acid is reacted with calcium carbonate at 20 °C. The reaction is repeated at 30 °C. Which statement about the second reaction is correct? A It is faster because there are fewer collisions per second between reacting particles. B It is faster because there are more collisions per second between reacting particles. C It is slower because there are fewer collisions per second between reacting particles. D It is slower because there are more collisions per second between reacting particles.
Mark scheme: B
Q22 · Which reaction is a redox reaction?
22 Which reaction is a redox reaction? A 2HCl + CaCO3 → CaCl 2 + CO2 + H2O B AgNO3 + KCl → AgCl + KNO3 C Ca(OH)2 + CO2 → CaCO3 + H2O D 2H2 + O2 → 2H2O
Mark scheme: D
Q23 · What is the trend shown by the elements across a period in the Periodic Table, from left…
23 What is the trend shown by the elements across a period in the Periodic Table, from left to right? A metals → non-metals B metals → non-metals → metals C non-metals → metals D non-metals → metals → non-metals
Mark scheme: A
Q24 · Which diagram represents the arrangement of atoms in an alloy?
24 Which diagram represents the arrangement of atoms in an alloy? A B C D
Mark scheme: A
Q25 · Which reaction does not take place in the blast furnace?
25 Which reaction does not take place in the blast furnace? A calcium carbonate → calcium oxide + carbon dioxide B calcium oxide + silicon dioxide → calcium silicate C iron oxide + carbon monoxide → iron + carbon dioxide D iron oxide + carbon dioxide → iron + carbon monoxide
Mark scheme: D
Q26 · Which process produces a gas that contributes to climate change?
26 Which process produces a gas that contributes to climate change? A the electrolysis of molten lead(II) bromide B the reaction of calcium with water C the reaction of copper oxide with dilute sulfuric acid D the thermal decomposition of calcium carbonate
Mark scheme: D
Q27 · Which statement about hydrocarbons is not correct?
27 Which statement about hydrocarbons is not correct? A Alkenes are made by cracking alkanes. B Butene decolourises bromine. C C2H4 is an alkene. D Ethanol is an alkane.
Mark scheme: D
Q28 · The diagram shows a speed-time graph for a falling object
28 The diagram shows a speed-time graph for a falling object. 20 speed m / s 10 0 0 1.0 2.0 time / s How far does the object fall in 2.0 seconds? A 5.0 m B 20 m C 30 m D 40 m
Mark scheme: C
Q29 · An unstretched spring obeys Hooke’s law and has a length of 10 cm
29 An unstretched spring obeys Hooke’s law and has a length of 10 cm. A load with a mass of 2.0 kg is hung from it, and its length becomes 14 cm. The load is now increased to 6.0 kg, and the new length of the spring is Y. The limit of proportionality is not reached. 10 cm 14 cm Y 2.0 kg 6.0 kg What is Y? A 22 cm B 26 cm C 30 cm D 42 cm
Mark scheme: A
Q30 · A copper block is pulled down a rough slope at a constant speed
30 A copper block is pulled down a rough slope at a constant speed. Which form of energy of the block increases? A chemical B gravitational C kinetic D thermal
Mark scheme: D
Q31 · A weightlifter lifts 150 kg through a distance of 2.0 m in a time of 1.5 s
31 A weightlifter lifts 150 kg through a distance of 2.0 m in a time of 1.5 s. The acceleration of free fall g is 10 m / s2. How much power does she produce? A 200 W B 450 W C 2000 W D 4500 W
Mark scheme: C
Q32 · On a summer’s day, hot air rises above hot roofs
32 On a summer’s day, hot air rises above hot roofs. What is the name of this process? A concentration B condensation C conduction D convection
Mark scheme: D
Q33 · The diagram shows part of the electromagnetic spectrum
33 The diagram shows part of the electromagnetic spectrum. Two regions are labelled P and Q. infra-red ultraviolet gamma P Q waves waves rays What type of radiation is P, and which radiation has the lower frequency, P or Q? lower radiation P frequency A visible light P B visible light Q C X-rays P D X-rays Q
Mark scheme: A
Q34 · The diagram represents a water wave moving into a region where the depth of water is…
34 The diagram represents a water wave moving into a region where the depth of water is different. region Y region X How do the speed and wavelength of the waves in region Y compare with their values in region X? speed in Y wavelength in Y A greater smaller B greater the same C smaller smaller D smaller the same
Mark scheme: C
Q35 · The diagram shows a ray of light as it enters a glass block
35 The diagram shows a ray of light as it enters a glass block. Which labelled angle is the angle of refraction? ray of light A B D C glass block
Mark scheme: C
Q36 · A student writes two sentences about sound waves
36 A student writes two sentences about sound waves. ‘A sound wave travels through the air as compressions and ......X...... .’ ‘The air at the compressions has a different ......Y...... from the air at ......X...... .’ What are the missing words, X and Y? X Y A rarefactions density B rarefactions state C refractions density D refractions state
Mark scheme: A
Q37 · A negative ion X is close to a positive ion and another negative ion
37 A negative ion X is close to a positive ion and another negative ion. Electrical forces act on ion X because of the charges in the other two ions. Which diagram shows the directions of the two forces acting on ion X? A B C D positive ion + + + + – ion X – ion X – ion X – ion X – – – – negative ion
Mark scheme: B
Q38 · The diagram shows four wires at the same temperature, made from the same metal
38 The diagram shows four wires at the same temperature, made from the same metal. The diagram is drawn to scale. Which wire has the least electrical resistance between its ends? A B C D
Mark scheme: B
Q39 · A resistor is connected in a circuit as shown
39 A resistor is connected in a circuit as shown. A V The reading on the ammeter is 2.0 A and the reading on the voltmeter is 4.0 V. What is the power produced in the resistor? A 0.50 W B 2.0 W C 6.0 W D 8.0 W
Mark scheme: D
Q40 · A circuit consists of two identical resistors, R1 and R2, and a battery
40 A circuit consists of two identical resistors, R1 and R2, and a battery. IB I1 R1 I2 R2 The current in the battery is IB. The current in R1 is I1 and the current in R2 is I2. How are IB, I1 and I2 related? A IB = I1 = I2 B IB > I1 and I1 = I2 C IB < I2 and I1 = I2 D IB > I1 > I2
Mark scheme: B
What was in this paper
The subtopics covered by these 40 questions, and how many questions each got. Open one in a new tab to see every Cambridge question on it.
3Electrolysis2Energy, work and power2Sexual reproduction in plants2Air quality and climate1Alloys and their properties1Arrangement of elements1Blood vessels1Cell structure1Diet1Drugs1Electrical circuits1Electromagnetic spectrum1Elements, compounds and mixtures1Energy flow1Enzymes1Exothermic and endothermic reactions1Extraction of metals1Forces1Formulas1Gas exchange in humans1General properties of waves1Heart1Light1Motion1Photosynthesis1Physical and chemical changes1Rate of reaction1Redox1Respiration1Separation and purification1Sexual reproduction in humans1Sound1Terminology1Transfer of thermal energy1What you needed in this session
Cambridge’s own grade thresholds for 2018 May/June, Paper 2 · Variant 3. A higher threshold means an easier paper — the bar moves with how the cohort did.