IGCSE Chemistry 0620 Paper 12, May/June 2025

Substance L melts at –7 °C and is a brown liquid at room temperature. What is the boiling point of pure L? A –77 °C B –7 °C to +7 °C C 59 °C D 107 °C to 117 °C

Which row describes how the volume of a gas changes when its temperature is increased at constant pressure and when its pressure is increased at constant temperature?

Nitrogen dioxide is a red-brown gas which is more dense than air. The diagram shows the arrangement of two gas jars which contain nitrogen dioxide and air separated with a glass plate. The glass plate is removed, and the gas jars are left for 24 hours. Which diagram shows the gas jars after 24 hours? A B C D

Which substance is a mixture of one element and one compound? A aqueous glucose B clean, dry air C oxygen dissolved in distilled water D stainless steel

Which statement defines the atomic number of an element? A the group number of the element B the mass of one atom of the element C the number of particles in the nucleus of one atom of the element D the number of protons in the nucleus of one atom of the element

What is different for isotopes of the same element? A nucleon number B number of electron shells C number of electrons in the outer electron shell D proton number

When sodium chloride is formed from its elements, each chlorine atom ......1...... one ......2...... . Which words correctly complete gaps 1 and 2?

In the molecules ${\mathrm{C}\mathrm{H}}_4$, $\mathrm{H}\mathrm{C}\mathrm{l}$ and ${\mathrm{H}}_2\mathrm{O}$, which atoms use all of their outer shell electrons in bonding? A C and Cl B C and H C Cl and H D H and O

Which substance has a giant covalent structure? A sodium chloride B ammonia C magnesium chloride D graphite

The diagrams show the structures of four molecules. Which statement about these molecules is correct? A All four molecules have different molecular formulae. B All four molecules have the same molecular formula. C Only two molecules have the same molecular formula. D Only three molecules have the same molecular formula.

The equation for the reaction of magnesium with oxygen is shown. $$2\mathrm{M}\mathrm{g}+{\mathrm{O}}_2\to 2\mathrm{M}\mathrm{g}\mathrm{O}$$ Which mass of oxygen reacts exactly with $6\text{ g}$ of magnesium? A $2\text{ g}$ B $4\text{ g}$ C $8\text{ g}$ D $16\text{ g}$

The diagram shows a simple electrolytic cell for an electrolysis experiment. Three parts of the electrolytic cell are labelled X, Y and Z. Which row shows the correct labels to replace X, Y and Z in the diagram?

Which equation represents the overall reaction that produces electricity in a hydrogen–oxygen fuel cell? A ${\mathrm{H}}_2+{\mathrm{O}}_2\to {\mathrm{H}}_2{\mathrm{O}}_2$ B $2{\mathrm{H}}_2\mathrm{O}\to 2{\mathrm{H}}_2+{\mathrm{O}}_2$ C $2{\mathrm{H}}_2+{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}$ D $2{\mathrm{H}}_2{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$

Which reaction pathway diagram shows the largest increase in the temperature of the surroundings? (The scale on the y-axis is the same in each diagram.) A B C D

Which process involves a chemical change? A dissolving copper(II) sulfate B distilling ethanol C freezing water D neutralising copper(II) oxide

The total volume of gas produced in two different experiments is measured against time. A graph of the results of the two experiments is shown. Which point shows the fastest rate of reaction? A B C D

The equation for the reaction of sulfur dioxide with oxygen is shown. $$2{\mathrm{S}\mathrm{O}}_2+{\mathrm{O}}_2\rightleftharpoons 2{\mathrm{S}\mathrm{O}}_3$$ What is meant by the symbol $\rightleftharpoons$? A redox reaction B reversible reaction C displacement reaction D thermal decomposition reaction

Which reactions are redox reactions? 1 the incomplete combustion of propane 2 the rusting of iron 3 the reaction of aqueous chloride ions with acidified aqueous silver nitrate 4 the thermal decomposition of calcium carbonate A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Which row describes an aqueous solution for the pH shown?

Which parts of the Periodic Table contain elements that only form basic oxides? A Group I and Period 3 B Group I only C Group VIII and Period 3 D Group VIII only

Which statement about elements in the Periodic Table is correct? A Elements in the same group of the Periodic Table have the same electronic configuration. B The atoms of the elements in Group VII form ions with a charge equal to the number of outer shell electrons minus 8. C The metallic character of the elements increases from left to right across a period. D The Periodic Table is an arrangement of elements in order of increasing nucleon number.

Which row identifies the trends in properties of the elements lithium to sodium to potassium?

Which statements about the halogens are correct? 1 They are all diatomic molecules. 2 They are all gases at room temperature and pressure. 3 The density of the elements increases down the group. 4 The reactivity of the elements increases down the group. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Zirconium is a transition element. What is a property of zirconium? A high density B does not conduct heat C forms white compounds only D low melting point

Some gases exist as single atoms, are unreactive and have eight electrons in their outer electron shell. Which gases fit this description? 1 helium 2 argon 3 oxygen 4 krypton A 1, 2 and 4 B 1 and 3 C 2 and 4 only D 3 only

Which statements about metals are correct? 1 Calcium reacts faster than magnesium with cold water. 2 Aluminium is more easily extracted than iron from its ore. 3 Copper reacts faster than iron with dilute hydrochloric acid. 4 Potassium and silver are both good conductors of electricity. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Four metals, P, Q, R and S, are separately reacted with dilute hydrochloric acid. The table shows the observation for each metal.

What is the order of reactivity of these four metals, from most reactive to least reactive? A $\mathrm{R}\to \mathrm{S}\to \mathrm{Q}\to \mathrm{P}$ B $\mathrm{P}\to \mathrm{S}\to \mathrm{Q}\to \mathrm{R}$ C $\mathrm{P}\to \mathrm{Q}\to \mathrm{S}\to \mathrm{R}$ D $\mathrm{Q}\to \mathrm{R}\to \mathrm{P}\to \mathrm{S}$

The diagram shows iron nails which are left for one week in separate test-tubes with the conditions shown. Which test-tubes show evidence of rusting after one week? A 1 and 3 B 1 only C 2 and 3 D 2 only

Pure metals can be combined to make alloys. Why are the alloys sometimes used rather than the metals they are made from? A Alloys are easier to extract and cheaper. B Alloys are easier to hammer into different shapes. C Alloys are harder and keep their shape better. D Alloys contain only atoms of the same size but pure metals do not.

In the experiment shown, $100{\text{ cm}}^3$ of clean, dry air is passed backwards and forwards through a tube containing heated copper until there is no further decrease in the volume of the air. All of the gas is pushed into one syringe. What is the final reading on this gas syringe? A $0{\text{ cm}}^3$ B $21{\text{ cm}}^3$ C $79{\text{ cm}}^3$ D $100{\text{ cm}}^3$

Sulfur dioxide, carbon monoxide and oxides of nitrogen are gaseous pollutants found in the air. Which pollutants contribute to acid rain? A carbon monoxide and sulfur dioxide B oxides of nitrogen and sulfur dioxide C oxides of nitrogen only D sulfur dioxide only

The formulae for three organic compounds are listed. 1 ${\mathrm{C}}_2{\mathrm{H}}_4$ 2 ${\mathrm{C}}_4{\mathrm{H}}_8$ 3 ${\mathrm{C}}_4{\mathrm{H}}_{10}$ Which compounds belong to the same homologous series? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Which fuel could be gasoline? A B C D

Three hydrocarbons are separately mixed with aqueous bromine. Which row gives the correct observation for each hydrocarbon?

Which compound is formed when ethene reacts with steam? A ethane B ethanoic acid C ethanol D poly(ethene)

Which statements about ethanoic acid are correct? 1 Its aqueous solution has a pH value of 10. 2 It reacts with metal carbonates to produce carbon dioxide gas. 3 It reacts with magnesium metal to produce hydrogen gas. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Which statement explains why plastic bags made from poly(ethene) accumulate in oceans? A Poly(ethene) is a saturated molecule. B Poly(ethene) is made from hydrocarbon monomers. C Poly(ethene) reacts with water. D Poly(ethene) does not decompose in water.

Which diagram shows the correct level of solvent at the start of a chromatography experiment? A B C D

Which process is used to separate a mixture of liquids with different boiling points? A dissolving B crystallisation C filtration D fractional distillation

Four different colourless solutions are each tested separately with aqueous sodium hydroxide and with acidified aqueous silver nitrate. Which row shows the results for sodium chloride?