IGCSE Chemistry 0620 Paper 22, May/June 2024

Which gas has the slowest rate of diffusion? A ${\mathrm{H}}_2$ B $\mathrm{N}{\mathrm{H}}_3$ C $\mathrm{C}{\mathrm{H}}_4$ D $\mathrm{C}{\mathrm{O}}_2$

Which statements about the position of the elements in the Periodic Table are correct? 1 Elements in the same group have similar chemical properties. 2 Elements in the same period have similar chemical properties. 3 Elements in the same group have the same number of electron shells. 4 Elements in the same group have the same number of outer shell electrons. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Which statements about isotopes are correct? 1 Isotopes are atoms of different elements with the same number of protons. 2 Isotopes of the same element have the same chemical properties. 3 Isotopes are atoms with the same relative atomic mass. 4 Isotopes of the same element have the same electronic configuration. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Which diagram shows the arrangement of the outer shell electrons in a molecule of water?

The structures of three substances are shown. Which substances are hard and have a high melting point? A 1, 2 and 3 B 1 only C 2 only D 2 and 3 only

Information about four substances, W, X, Y and Z, is shown.

W, X, Y and Z are graphite, poly(ethene), sodium chloride and silicon(IV) oxide but not in that order. What are W, X, Y and Z?

The structure of glycine is shown. Which row is correct?

The incomplete equation for photosynthesis is shown. $$w\mathrm{C}{\mathrm{O}}_2+x{\mathrm{H}}_2\mathrm{O}\to \mathrm{P}+y{\mathrm{O}}_2$$ Compound P is a product of the reaction. Which row describes the values of $w$, $x$ and $y$ and gives the empirical formula of compound P?

The concentration and volume of an aqueous alkali are known. Which additional information is required to calculate the number of moles of acid needed to neutralise the aqueous alkali? A the concentration of the acid B the equation for the acid–alkali reaction C the formula of the acid D the volume of the acid required for neutralisation

Which statement about electrolysis is correct? A Electrons move through the electrolyte from the cathode to the anode. B Electrons move in the external circuit towards the cathode. C Negative ions move in the external circuit towards the anode. D Positive ions move through the electrolyte towards the anode.

Aqueous copper(II) sulfate is electrolysed using copper electrodes. What is the half-equation for the reaction at the cathode? A $2{\mathrm{H}}^{+}+2{\mathrm{e}}^{-}\to {\mathrm{H}}_2$ B $4\mathrm{O}{\mathrm{H}}^{-}\to {\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}+4{\mathrm{e}}^{-}$ C $\mathrm{C}\mathrm{u}\to \mathrm{C}{\mathrm{u}}^{2+}+2{\mathrm{e}}^{-}$ D $\mathrm{C}{\mathrm{u}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{C}\mathrm{u}$

Three statements about activation energy, $E_{\mathrm{a}}$, are listed. 1 Colliding particles must have at least $E_{\mathrm{a}}$ before they can react. 2 $E_{\mathrm{a}}$ for exothermic reactions is always greater than for endothermic reactions. 3 $E_{\mathrm{a}}$ is always endothermic. Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

A student adds excess magnesium ribbon to $10{\text{ cm}}^3$ of $0.5\text{ mol}\mathrm{/}{\text{dm}}^3$ sulfuric acid. The hydrogen gas produced is collected and its total volume is measured every 10 seconds. The experiment is repeated with $5{\text{ cm}}^3$ of $0.5\text{ mol}\mathrm{/}{\text{dm}}^3$ sulfuric acid added to $5{\text{ cm}}^3$ of water using the same mass of magnesium ribbon. Which line on the graph shows the results of the second experiment?

The equation represents the reversible reaction between ethene and steam. $${\mathrm{C}}_2{\mathrm{H}}_4(\mathrm{g})+{\mathrm{H}}_2\mathrm{O}(\mathrm{g})\rightleftharpoons {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{O}\mathrm{H}(\mathrm{g})\mathrm{\Delta }H\text{ is negative}$$ Which row describes the conditions that produce the greatest yield of ethanol?

Which row identifies the pressure and the catalyst used for the conversion of sulfur dioxide to sulfur trioxide in the Contact process?

Which equation represents a redox reaction? A $\mathrm{A}\mathrm{g}\mathrm{N}{\mathrm{O}}_3+\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}\to \mathrm{A}\mathrm{g}\mathrm{C}\mathrm{l}+\mathrm{N}\mathrm{a}\mathrm{N}{\mathrm{O}}_3$ B $\mathrm{P}\mathrm{C}{\mathrm{l}}_5+4{\mathrm{H}}_2\mathrm{O}\to {\mathrm{H}}_3\mathrm{P}{\mathrm{O}}_4+5\mathrm{H}\mathrm{C}\mathrm{l}$ C $3\mathrm{F}\mathrm{e}+4{\mathrm{H}}_2\mathrm{O}\to \mathrm{F}{\mathrm{e}}_3{\mathrm{O}}_4+4{\mathrm{H}}_2$ D $\mathrm{M}\mathrm{g}\mathrm{C}{\mathrm{O}}_3+2\mathrm{H}\mathrm{C}\mathrm{l}\to \mathrm{M}\mathrm{g}\mathrm{C}{\mathrm{l}}_2+\mathrm{C}{\mathrm{O}}_2+{\mathrm{H}}_2\mathrm{O}$

The equation for the reaction between aluminium and copper(II) oxide is shown. $$2\mathrm{A}\mathrm{l}+3\mathrm{C}\mathrm{u}\mathrm{O}\to \mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3+3\mathrm{C}\mathrm{u}$$ Which statements about this equation are correct? 1 The oxidation number of the aluminium reactant is $+2$. 2 The oxidation number of the aluminium in the product is $+6$. 3 The oxidation number of the copper in the reactant is $+2$. 4 The oxidation number of the copper product is 0. A 1, 2 and 3 B 1 and 2 only C 3 and 4 D 4 only

What is the colour of thymolphthalein in dilute hydrochloric acid? A blue B red C yellow D colourless

Two acids, P and Q, with the same concentration and volume are reacted separately with the same mass of magnesium ribbon. The reactions produce the same total volume of hydrogen gas but acid Q reacts much more slowly than acid P. Which explanation for the difference between P and Q is correct? A Acid P has a higher pH than acid Q. B Acid P has a lower concentration of hydrogen ions. C Acid Q is partially dissociated and acid P is fully dissociated. D Acid Q is a proton acceptor.

Which process is not used in the preparation of an insoluble salt? A filtration B washing C crystallisation D drying

Lithium and potassium are metals in Group I of the Periodic Table. Lithium has a melting point of $181{}^{\circ }\mathrm{C}$ and a density of $0.53\text{ g}\mathrm{/}{\text{cm}}^3$. Which row describes the melting point and density of potassium?

Which statements about transition elements are correct? 1 They have a low density. 2 They form ions with variable oxidation numbers. 3 They have a high melting point. 4 They form only colourless compounds. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Which statements describe the elements in Group VIII of the Periodic Table? 1 Their atoms have full outer electron shells. 2 They are unreactive metals. 3 They are monatomic gases. 4 They are diatomic gases. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Four metals, Q, R, S and T, are each added to separate samples of water, steam and dilute hydrochloric acid. The results are shown.

Which statements are correct? 1 R is the least reactive metal. 2 T could be potassium. 3 S is more reactive than Q and R. 4 Metals generally react faster with steam than they react with water. A 1, 2 and 4 B 1 and 2 only C 2 and 3 D 3 and 4

Metal X acts as a sacrificial metal to prevent iron from corroding. Metal X does not act as a sacrificial metal to prevent aluminium from corroding. What is X? A copper B magnesium C silver D zinc

Which equation represents the reduction of a compound found in hematite in the blast furnace? A $2\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3\to 4\mathrm{A}\mathrm{l}+3{\mathrm{O}}_2$ B $\mathrm{C}\mathrm{a}\mathrm{O}+\mathrm{S}\mathrm{i}{\mathrm{O}}_2\to \mathrm{C}\mathrm{a}\mathrm{S}\mathrm{i}{\mathrm{O}}_3$ C $2\mathrm{F}\mathrm{e}\mathrm{O}+\mathrm{C}\mathrm{O}\to \mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3+\mathrm{C}$ D $\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3+3\mathrm{C}\mathrm{O}\to 2\mathrm{F}\mathrm{e}+3\mathrm{C}{\mathrm{O}}_2$

Which statements about the treatment of domestic water supplies are correct? 1 Filtration is used to remove insoluble substances from the water. 2 Sedimentation is used to remove soluble substances from the water. 3 Carbon is used to remove tastes and odours from the water. 4 Chlorine is used to lower the pH of the water. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Which statement about water is correct? A It turns anhydrous copper(II) sulfate from pink to blue. B It turns anhydrous copper(II) sulfate from white to blue. C It turns cobalt(II) chloride paper from blue to white. D It turns cobalt(II) chloride paper from pink to blue.

Cupronickel is used to make coins. The arrangement of atoms in cupronickel is shown. Which kind of substance is cupronickel? A an alloy B an isotope C a compound D a transition element

Which physical properties are typical of all metals? 1 good heat conductivity 2 low density 3 malleability A 1 and 2 B 1 and 3 C 2 and 3 D 3 only

Which oxide is used to neutralise acidic gases in flue gas desulfurisation? A calcium oxide B carbon dioxide C nitrogen oxide D sulfur dioxide

Some information about three gases, P, Q and R, is listed. • Gas P forms when magnesium reacts with dilute hydrochloric acid. • Gas Q makes up 78% of the air. • Gas R forms when gas P reacts with gas Q. What is gas R? A ammonia B methane C nitrogen dioxide D water vapour

Which formula represents an alkene? A $\mathrm{C}{\mathrm{H}}_4$ B ${\mathrm{C}}_2{\mathrm{H}}_4$ C ${\mathrm{C}}_2{\mathrm{H}}_6$ D ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{O}\mathrm{H}$

The structures of two compounds used to make an ester are shown. What is the name of the ester? A ethyl propanoate B propyl ethanoate C ethyl ethanoate D propyl propanoate

Which statement about a homologous series is correct? A All members have the same general formula. B All members have the same molecular formula. C All members have similar physical properties. D Members show a trend in their chemical properties.

Which statements about aqueous ethanoic acid are correct? 1 It contains the functional group –COOH. 2 It reacts with carbonates to produce hydrogen. 3 It turns universal indicator paper blue. 4 It has a pH lower than pH 7. A 1 and 2 B 1 and 3 C 1 and 4 D 2 and 4

Alkenes react with steam in an addition reaction. Some alkenes produce only one alcohol product. Some alkenes produce two different alcohols which are structural isomers. Which row gives the number of alcohol isomers formed when ethene reacts with steam and when propene reacts with steam?

What is an advantage of manufacturing ethanol by fermentation rather than by the addition of steam to ethene? A No gases that cause global warming are produced. B The ethanol that is produced is pure. C Fermentation is a fast process. D Fermentation uses renewable raw materials.

The diagram shows the structure of a polymer. Which structure represents the monomer for this polymer?

Which piece of apparatus is used to measure $24.5{\text{ cm}}^3$ of gas produced during a reaction? A beaker B conical flask C measuring cylinder D volumetric pipette