IGCSE Sciences - Co-Ordinated (0973) — May–June 2023, Paper 21
40 questions · every question answerable online with instant point-by-point AI marking against the official mark scheme.
Start with Question 1 →What is meant by respiration? A protein synthesis B sweating to lose heat C the function of lungs D the release of energy
Answer this question and get it marked →What is meant by osmosis? A the net movement of water molecules from a region of higher water potential to a region of lower water potential through a cell wall B the net movement…
Answer this question and get it marked →Linoleic acid is a fatty acid. Which larger molecule may contain linoleic acid? A glycogen B oil C protein D starch
Answer this question and get it marked →Which row about enzymes is correct? [Table: rows A-D each marked true/false against statements: 'each enzyme catalyses many different reactions', 'the active site is the part of…
Answer this question and get it marked →An experiment is set up to investigate the effect of changing the light intensity on the rate of photosynthesis. The lamp is moved in 10 cm intervals away from the plant and the…
Answer this question and get it marked →Some processes that occur in the alimentary canal and associated organs are listed: 1 absorption, 2 assimilation, 3 digestion, 4 egestion, 5 ingestion. [Diagrams A-D: each links…
Answer this question and get it marked →What is the sequence of blood vessels that a red blood cell passes through as it travels from the vena cava to the kidney? A pulmonary artery - pulmonary vein - aorta - renal…
Answer this question and get it marked →Which statement about anaerobic respiration is correct? A It does not cause an oxygen debt. B It occurs in the muscles during vigorous exercise. C It uses oxygen to release energy…
Answer this question and get it marked →What is the function of the cornea? A It carries impulses to the brain. B It controls how much light enters the pupil. C It focuses light onto the retina. D It refracts light.
Answer this question and get it marked →In a plant, what leads to offspring that are genetically identical to the parent? A asexual reproduction B insect pollination C seed germination D sexual reproduction
Answer this question and get it marked →The diagram shows eggs and sperm containing sex chromosomes. Eggs: 1 = XX, 2 = X, 3 = XY, 4 = Y. Sperm: 5 = X, 6 = Y, 7 = XX, 8 = XY. Which row gives the correct combination of…
Answer this question and get it marked →The diagram shows a food web. Producers: grass, hogweed, ivy, oak tree. Primary consumers: bank voles, goldfinches, aphids, caterpillars. Wrens feed on aphids/caterpillars;…
Answer this question and get it marked →What causes eutrophication? A combustion of fossil fuels B cutting down of forests C discarded plastic rubbish D overuse of nitrogen-containing fertiliser
Answer this question and get it marked →An aqueous salt solution contains an insoluble impurity. Which processes are used to obtain pure salt crystals? A distillation then crystallisation B distillation then…
Answer this question and get it marked →The element phosphorus burns in air, as shown. 4P + 5O2 - P4O10 What does the formula P4O10 show? A a mixture of atoms of two elements B a mixture of molecules of two elements C a…
Answer this question and get it marked →Which row describes an atom that has the nucleon number 24? A protons 8, neutrons 8, electrons 8 B protons 12, neutrons 12, electrons 12 C protons 21, neutrons 24, electrons 21 D…
Answer this question and get it marked →Which symbol equation is not balanced? A C3H8 + 5O2 - 3CO2 + 4H2O B Fe3O4 + 2H2 - 3Fe + 2H2O C Mg(OH)2 + 2HCl - MgCl2 + 2H2O D 2Na + 2H2O - 2NaOH + H2
Answer this question and get it marked →Sodium hydroxide is manufactured by the electrolysis of concentrated aqueous sodium chloride. During the process, a gas is given off at each electrode and the aqueous sodium…
Answer this question and get it marked →Which row explains why increasing the concentration of a reactant increases the rate of reaction? A proportion of particles with the minimum energy to react: increases; collision…
Answer this question and get it marked →Which statements about neutralisation are correct? 1 Acids and bases produce water when they neutralise each other. 2 During neutralisation, bases transfer protons to acids. 3…
Answer this question and get it marked →The properties of some substances are listed. 1 form acidic oxides 2 have high melting points 3 act as catalysts 4 form coloured compounds What are the properties of transition…
Answer this question and get it marked →Which atmospheric pollutant is removed from air by lime? A ammonia B carbon monoxide C hydrocarbons D sulfur dioxide
Answer this question and get it marked →Which row describes how hydrogen and nitrogen are obtained for use in the Haber process? A hydrogen electrolysis of sulfuric acid; nitrogen catalytic reduction of nitrogen oxides…
Answer this question and get it marked →Equations representing reactions in the Contact process are listed. reaction 1 S + O2 - SO2 reaction 2 2SO2 + O2 - 2SO3 (reversible) reaction 3 H2SO4 + SO3 - H2S2O7 reaction 4…
Answer this question and get it marked →Which statements about limestone are correct? 1 Its main constituent is calcium oxide. 2 It can be used to manufacture lime. 3 It thermally decomposes to release carbon dioxide. 4…
Answer this question and get it marked →Petroleum is separated into fractions by fractional distillation. Information about uses of some fractions and positions in the fractionating column is shown. 1 gasoline: making…
Answer this question and get it marked →Which structure represents the addition polymer made from the monomer propene, C3H6? [Structures A-D: repeat units with CH3 and H groups on the carbon chain; A is the correct…
Answer this question and get it marked →The diagram shows the speed-time graph for a moving object. The line rises linearly from 0 m/s at time 0 to 20 m/s at time 4.0 s. [Speed-time graph: from (0, 0) to (4.0, 20).]…
Answer this question and get it marked →The diagram shows a triangular sheet of metal with sides of length 50 cm, 40 cm and 30 cm. The sheet is free to move about a pivot at the top corner. A cord is attached to the…
Answer this question and get it marked →A machine has useful output energy of 1000 J and wasted energy of 300 J. Which expression is used to calculate the efficiency of the machine? A 300 / (1000 + 300) x 100% B 300 /…
Answer this question and get it marked →Which statement about thermal radiation is correct? A A dull surface is a good absorber and a good reflector of thermal radiation. B A dull surface is a poor absorber and a poor…
Answer this question and get it marked →A student stands in front of a plane mirror on a wall. Which statement about the image of the student is not correct? A The image is laterally inverted (left to right). B The…
Answer this question and get it marked →A wave has a frequency of 3.0 MHz and a speed of 1500 m/s. What is the wavelength of the wave? A 5.0 x 10^-4 m B 0.50 m C 500 m D 4500 m
Answer this question and get it marked →The diagram shows a ray of light passing from air into plastic. The angle of incidence in air is 30 degrees from the normal and the angle of refraction in the plastic is 18…
Answer this question and get it marked →Two insulators are charged by rubbing them with a cloth. After this, the charged insulators repel each other. Which statement is a possible description of how the insulators…
Answer this question and get it marked →A battery of e.m.f. V is connected across a resistor of resistance R. There is a current in the resistor. [Circuit diagram: battery V connected to resistor R, current flowing.]…
Answer this question and get it marked →An electric kettle is connected to a 250 V supply. The current in the heating element of the kettle is 10 A. How much electrical energy is transferred in 3.0 minutes? A 75 J B…
Answer this question and get it marked →Fuses are used in domestic electric circuits. Which statement about fuses is correct? A A fuse is connected in the live wire. B A fuse is connected in the neutral wire. C A 3.0 A…
Answer this question and get it marked →A radioactive nucleus 238/92 U decays into a thorium (Th) nucleus by emitting an alpha-particle. What is the symbol for the thorium nucleus formed? A 234/90 Th B 234/92 Th C…
Answer this question and get it marked →The diagrams show a beam of beta-particles passing into an electric field and another beam of beta-particles passing into a magnetic field. In the electric field the positive…
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