IGCSE Chemistry (0971) — May–June 2024, Paper 21
40 questions · every question answerable online with instant point-by-point AI marking against the official mark scheme.
Start with Question 1 →A gas is heated. The pressure is kept constant. Which statement describes the behaviour of the particles in the gas? A The particles move faster and become closer together. B The…
Answer this question and get it marked →A mixture of ice and water is left to stand and the ice melts. Which row describes what happens as the ice is melting? Columns: temperature of mixture, energy change. A increases,…
Answer this question and get it marked →Hydrogen chloride gas [Mr: HCl, 36.5] is released at P in the apparatus shown, and the universal indicator paper turns red after 38 s. The experiment is repeated using sulfur…
Answer this question and get it marked →Four statements about atoms are listed. 1 The centre of an atom is positively charged. 2 Protons and electrons are located in the nucleus. 3 Protons and electrons have the same…
Answer this question and get it marked →The electronic configurations of two elements are given: element L 2,8,8,1; element M 2,8,4. Which row identifies the group number and the period number for element L and element…
Answer this question and get it marked →Which statement explains why isotopes of the same element have the same chemical properties? A They have different numbers of protons in their nucleus. B They have different…
Answer this question and get it marked →Which statements about potassium chloride are correct? 1 It conducts electricity when solid because its ions are free to move. 2 It has a high melting point because it has strong…
Answer this question and get it marked →How many electrons are shared in one molecule of nitrogen and in one molecule of ethene? Columns: nitrogen, ethene. A 2, 12 B 2, 8 C 6, 12 D 6, 8
Answer this question and get it marked →What is the total number of electrons in one molecule of ammonia, NH3? A 6 B 8 C 10 D 11
Answer this question and get it marked →When heated, copper(II) oxide, CuO, reacts with ammonia, NH3: 3CuO + 2NH3 - 3Cu + N2 + 3H2O. 8.5 g of ammonia reacts with an excess of copper(II) oxide to produce 26.4 g of…
Answer this question and get it marked →What is the empirical formula of ethanoic acid? A CHO B CH2O C C2H2O D C2H4O2
Answer this question and get it marked →Magnesium chloride, MgCl2, contains magnesium ions and chloride ions. How many chloride ions are present in two moles of magnesium chloride? A 6.02 x 10^23 B 1.204 x 10^24 C 2.408…
Answer this question and get it marked →A metal object is electroplated with copper. One electrode is the metal object and the other electrode is copper. The electrolyte is aqueous copper(II) sulfate. Which row shows…
Answer this question and get it marked →Which statement about electrolysis is correct? A Chemical energy is converted to electrical energy. B Electrons flow through the electrolyte. C Ionic compounds are broken down. D…
Answer this question and get it marked →The reaction between hydrogen and oxygen releases 486 kJ/mol of energy: 2H2(g) + O2(g) - 2H2O(g). The bond energy of H-H is 436 kJ/mol and that of H-O is 464 kJ/mol. What is the…
Answer this question and get it marked →Which reaction pathway diagram shows the reaction that will give out the most energy? The scale on the y-axis is the same in each diagram. Four reaction pathway diagrams A-D are…
Answer this question and get it marked →When calcium carbonate is heated strongly, a gas is given off. Which word describes this change? A chemical B exothermic C physical D reduction
Answer this question and get it marked →Powdered magnesium carbonate is added to excess dilute hydrochloric acid. The total volume of gas produced is measured over time; a graph rising and levelling off at about 180 cm3…
Answer this question and get it marked →Which statements explain why increasing the temperature changes the rate of a chemical reaction? 1 It increases the activation energy. 2 It increases the frequency of collisions…
Answer this question and get it marked →Hydrogen is made by reacting carbon with steam: C(s) + H2O(g) <- H2(g) + CO(g). The forward reaction is endothermic. Which row describes changes in the pressure and the…
Answer this question and get it marked →Which row shows the conditions used for the conversion of sulfur dioxide to sulfur trioxide in the Contact process? Columns: pressure / atm, temperature / degrees C, catalyst. A…
Answer this question and get it marked →The equation for the reaction of magnesium with carbon dioxide is: 2Mg + CO2 - 2MgO + C. Which statement about this reaction is correct? A Magnesium is oxidised and carbon dioxide…
Answer this question and get it marked →Chlorine displaces bromine from aqueous potassium bromide. The ionic equation is: Cl2 + 2Br- - 2Cl- + Br2. Which statement about this reaction is correct? A Bromide ions act as an…
Answer this question and get it marked →Which gas is produced when ammonium chloride is warmed with aqueous sodium hydroxide? A ammonia B chlorine C hydrogen D nitrogen
Answer this question and get it marked →Which equation represents a solution of ethanoic acid in water? A HCOOH(aq) <- HCOO-(aq) + H+(aq) B HCOOH(aq) - HCOO-(aq) + H+(aq) C CH3COOH(aq) <- CH3COO-(aq) + H+(aq) D…
Answer this question and get it marked →Four statements about the reactions of oxides with dilute hydrochloric acid and with aqueous sodium hydroxide are listed. 1 Aluminium oxide reacts with both dilute hydrochloric…
Answer this question and get it marked →Which statement about elements in Period 3 of the Periodic Table is correct? A Aluminium is a non-metal in Group III. B Argon is in Group VIII and has eight electrons in its outer…
Answer this question and get it marked →Which row describes the structure of Group VII elements and the trend in their reactivity down the group? Columns: structure, reactivity down Group VII. A diatomic, increases B…
Answer this question and get it marked →Some information about four elements, P, Q, R and S, is shown (melting point in degrees C, density in g/cm3, colour of chloride): P 1247, 7.43, pink; Q 1410, 2.33, white; R 1910,…
Answer this question and get it marked →Propanoic acid is a carboxylic acid. It has similar chemical properties to ethanoic acid. Which statements are correct? 1 Aqueous propanoic acid is a weaker acid than dilute…
Answer this question and get it marked →Iron rusts in the presence of oxygen and water. Which statements about the rusting of iron are correct? 1 Anhydrous iron(II) oxide is produced when iron rusts. 2 Iron rusts more…
Answer this question and get it marked →An iron nail is added to aqueous copper(II) sulfate and a different iron nail is added to aqueous magnesium sulfate. Results: iron nail in aqueous copper(II) sulfate - nail is…
Answer this question and get it marked →Which pollutant leads to the deoxygenation of water in ponds and lakes? A fertilisers containing nitrates and phosphates B toxic metal compounds C combustion products of fossil…
Answer this question and get it marked →Which statement identifies a sample of water as pure? A It melts at room temperature. B It turns anhydrous copper(II) sulfate blue. C It turns hydrated cobalt(II) chloride from…
Answer this question and get it marked →Oxides of nitrogen are produced by car engines. In a catalytic converter oxides of nitrogen are removed by reacting them with compound X. Which row describes the type of reaction…
Answer this question and get it marked →What is a disadvantage of producing ethanol using the catalytic addition of steam to ethene? A the energy cost is low B the process is continuous C the process uses a…
Answer this question and get it marked →Which statement about the polymer PET is correct? A It can be broken down into its monomers and re-polymerised. B It is an addition polymer. C It is a polyamide. D It is made from…
Answer this question and get it marked →The formulae of five compounds are listed. 1 C4H10 2 C2H5OH 3 C4H9OH 4 C4H9COOH 5 C5H11OH Which compounds are in the same homologous series? A 1, 3 and 4 B 2, 3 and 5 C 3 and 4…
Answer this question and get it marked →Propane reacts with chlorine. Which statements about this reaction are correct? 1 Ultraviolet light is used to provide the activation energy. 2 Propane undergoes an addition…
Answer this question and get it marked →Which statement about chromatography is correct? A It is not possible for two different substances to have the same Rf value. B It is only possible to use chromatography on…
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