IGCSE Chemistry (0620) — October–November 2023, Paper 23
40 questions · every question answerable online with instant point-by-point AI marking against the official mark scheme.
Start with Question 1 →A sample of a gas occupies 340 cm3 at room temperature and pressure. The temperature and pressure are both increased, but the volume occupied by the gas remains 340 cm3. Which row…
Answer this question and get it marked →Which statements about the rate of diffusion of the gases ammonia, carbon monoxide, nitrogen and oxygen are correct? 1 Nitrogen and carbon monoxide will diffuse at the same rate.…
Answer this question and get it marked →The structure of an atom of element X is shown. key 5p = electron 6n n = neutron p = proton What is element X? A boron B carbon C sodium D sulfur
Answer this question and get it marked →Which statement explains why isotopes of an element have the same chemical reactions? A They have different numbers of neutrons. B They have ions with different numbers of…
Answer this question and get it marked →Magnesium reacts with oxygen to form magnesium oxide. What happens to magnesium atoms and oxygen atoms during this reaction? A Magnesium and oxygen share two electrons. B…
Answer this question and get it marked →Which row about the properties of both diamond and silicon(IV) oxide is correct? conductor type of of electricity molecule A yes giant covalent B yes simple covalent C no giant…
Answer this question and get it marked →The equation represents the reaction between solid magnesium oxide and dilute hydrochloric acid to form magnesium chloride and water. MgO + 2HCl → MgCl 2 + H2O Which row shows the…
Answer this question and get it marked →Which substance is a mixture? A air B graphite C oxygen D water
Answer this question and get it marked →The number of moles of atoms X, Y and Z, in a compound, are shown. atom moles X 0.6 Y 1.2 Z 0.3 What is the formula of the compound? A XY2Z4 B XY4Z2 C X2YZ4 D X2Y4Z
Answer this question and get it marked →1.0 mol of silver nitrate, AgNO3, contains 1.2 × 1024 ions. How many ions are there in 0.25 mol of iron(III) oxide, Fe2O3? A 1.5 × 1023 B 3.0 × 1023 C 7.5 × 1023 D 3.0 × 1024
Answer this question and get it marked →Concentrated aqueous magnesium bromide is electrolysed using carbon electrodes. Which equations represent the reactions occurring at each electrode? positive electrode negative…
Answer this question and get it marked →Aqueous copper(II) sulfate is electrolysed using carbon electrodes. Which statement is correct? A Bubbles of hydrogen gas are formed at the anode. B Bubbles of oxygen gas are…
Answer this question and get it marked →When water is added to anhydrous iron(III) chloride, FeCl 3, hydrated iron(III) chloride, FeCl 3•6H2O, is formed and energy is given out. FeCl 3 + 6H2O FeCl 3•6H2O Which reaction…
Answer this question and get it marked →Ethene reacts with hydrogen. The equation is shown. C2H4 + H2 → C2H6 The bond energies are shown. bond energy bond in kJ / mol C–C +350 C=C +610 C–H +410 H–H +436 What is the…
Answer this question and get it marked →Statements about four different acids are listed. ● A 0.0100 mol / dm3 solution of hydrochloric acid has a pH of 2. ● A 0.0100 mol / dm3 solution of ethanoic acid has a pH of 3.4.…
Answer this question and get it marked →Anhydrous cobalt(II) chloride is blue and turns pink when water is added. How is this reaction reversed? A adding dilute acid B filtering C heating D cooling
Answer this question and get it marked →The reaction between hydrogen and nitrogen is reversible. The forward reaction is exothermic. N2(g) + 3H2(g) 2NH3(g) Which change to the conditions would increase the yield of…
Answer this question and get it marked →Ethanol can be turned into ethanoic acid by passing it over hot copper(II) oxide. CH3CH2OH + 2CuO → CH3COOH + H2O + 2Cu What is this type of reaction? A precipitation B redox C…
Answer this question and get it marked →When heated strongly, silicon(IV) oxide reacts with carbon. SiO2 + 2C → Si + 2CO Which term describes what happens to silicon(IV) oxide? A thermal decomposition B neutralisation C…
Answer this question and get it marked →Which statement about aqueous weak acids is correct? A Weak acids are always dilute aqueous solutions. B Weak acids dissociate fully in aqueous solution. C When a weak acid is…
Answer this question and get it marked →Which oxides are basic? 1 calcium oxide 2 sodium oxide 3 iron(II) oxide A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only
Answer this question and get it marked →Zinc oxide is an amphoteric oxide. Zinc oxide is added to excess dilute hydrochloric acid. Zinc oxide is added to excess aqueous sodium hydroxide. Which row describes the…
Answer this question and get it marked →Which row shows properties of an element that is in the same group of the Periodic Table as lithium? electrical density conductivity in g / cm3 A high 0.97 B high 8.93 C low 0.07…
Answer this question and get it marked →The elements in Group VII include chlorine, bromine and iodine. Which statements are correct? 1 Iodine is more dense than chlorine. 2 Iodine displaces chlorine from a solution…
Answer this question and get it marked →Cobalt is a transition element. What is a property of cobalt? A It can form coloured compounds. B It is a poor electrical conductor. C It has a low density. D It has a low melting…
Answer this question and get it marked →Which metal has variable oxidation numbers? A aluminium B calcium C copper D sodium
Answer this question and get it marked →Which statement about alloys is correct? A Alloys are pure metal elements. B At least two or more metals react together to make alloys. C Alloys can be harder and stronger than a…
Answer this question and get it marked →A metal M is between sodium and magnesium in the reactivity series. Which reactions occur with M and its oxide? M can be extracted M reacts with steam by heating its oxide with…
Answer this question and get it marked →The diagrams show experiments to investigate rusting of iron nails. 1 2 3 layer of oil tap salt boiled water water water In which test-tubes do the nails rust? A 1, 2 and 3 B 1…
Answer this question and get it marked →Which equation represents a reaction that takes place when iron is extracted from its ore in the blast furnace? A CaO + SiO2 → CaSiO3 B CaO + CO2 → CaCO3 C 2CO → C + CO2 D 2Fe +…
Answer this question and get it marked →Some uses of water are listed. 1 for drinking 2 in chemical reactions 3 in swimming pools 4 in washing For which uses is it necessary to chlorinate the water? A 1 and 2 B 1 and 3…
Answer this question and get it marked →Oxides of nitrogen are formed in car engines and are a source of air pollution. To decrease this pollution, catalytic converters are fitted to car exhausts. What happens to the…
Answer this question and get it marked →Which pair of compounds are structural isomers of each other? A CH3CH2CH3 and CH3CH2CH2CH3 B CH2=CHCH3 and CH3CH=CH2 C CH2(OH)CH2CH3 and CH3CH2CH2OH D CH3CH2CH2COOH and…
Answer this question and get it marked →Methane reacts with chlorine in sunlight. CH4 + Cl 2 → CH3Cl + HCl Which statements about this reaction are correct? 1 It is a substitution reaction. 2 It is an addition reaction.…
Answer this question and get it marked →Propene reacts with bromine to give one product only. What is the formula of the product? A CH3CH2CHBr2 B CH2BrCH2CH2Br C CH3CHBrCH2Br D CH3CH2CH2Br
Answer this question and get it marked →Ethanol can be manufactured by fermentation or by the catalytic addition of steam to ethene. Which statements describe an advantage of manufacturing ethanol by fermentation? 1 The…
Answer this question and get it marked →A compound with the formula CH3COOC2H5 is formed from ethanol in two separate reactions. reaction 1 Ethanol reacts to form ethanoic acid. reaction 2 Ethanoic acid and ethanol…
Answer this question and get it marked →The flow diagram shows how poly(ethene) may be made from petroleum. 1 2 3 petroleum fuel oil ethene poly(ethene) What are stages 1, 2 and 3? 1 2 3 A cracking polymerisation…
Answer this question and get it marked →Rf values are used to identify unknown substances using paper chromatography. Which statements about Rf values are correct? 1 Rf values are always less than 1.0. 2 Rf value =…
Answer this question and get it marked →The results of some tests on an aqueous solution of substance X are listed. 1 A cream precipitate is produced when adding aqueous silver nitrate. 2 Adding aqueous sodium hydroxide…
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