IGCSE Chemistry 0620 Paper 12, May/June 2023

Four physical changes of ethanol are listed. 1 condensation 2 evaporation 3 freezing 4 boiling In which changes do the particles move further apart? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Which statement explains why water is a compound? A The hydrogen and oxygen atoms in a molecule of water can only be separated by chemical means. B The hydrogen and oxygen atoms in a molecule of water can be separated using physical means. C The number of hydrogen and oxygen atoms in a molecule of water is variable. D Water has the same chemical properties as both hydrogen and oxygen.

An atom of element X contains: ● 5 protons ● 6 neutrons ● 5 electrons. Which statements about element X are correct? 1 X has an atomic number of 6. 2 X has a nucleon number of 11. 3 X is in Group II of the Periodic Table. 4 X is in the second period of the Periodic Table. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Which row describes properties of lithium fluoride?

Ammonia, ${\mathrm{N}\mathrm{H}}_3$, is a covalent molecule. Which diagram shows the outer-shell electron arrangement in a molecule of ammonia? A B C D

Which substance has a giant covalent structure? A ethanol B graphite C methane D sodium chloride

Sodium burns in oxygen to form sodium oxide. What is the balanced equation for the reaction? A $4\mathrm{N}\mathrm{a}+2\mathrm{O}\to 2{\mathrm{N}\mathrm{a}}_2\mathrm{O}$ B $4\mathrm{N}\mathrm{a}+{\mathrm{O}}_2\to 2{\mathrm{N}\mathrm{a}}_2\mathrm{O}$ C $2{\mathrm{N}\mathrm{a}}_2+{\mathrm{O}}_2\to 2{\mathrm{N}\mathrm{a}}_2\mathrm{O}$ D $2{\mathrm{N}\mathrm{a}}_2+2\mathrm{O}\to 2{\mathrm{N}\mathrm{a}}_2\mathrm{O}$

What is the relative formula mass of ${\mathrm{M}\mathrm{g}(\mathrm{O}\mathrm{H})}_2$? A 21 B 30 C 42 D 58

Dilute sulfuric acid is electrolysed using inert electrodes. The apparatus is set up as shown. $30{\text{ cm}}^3$ of a gas is collected at the cathode. A different gas is collected at the anode. Which row is correct?

Four statements about hydrogen fuel cells are listed. 1 The fuel cell converts chemical energy into electrical energy. 2 In the fuel cell, hydrogen combines with oxygen. 3 Carbon dioxide and water are produced in the fuel cell. 4 The hydrogen fuel is extracted from the air. Which statements are correct? A 1 and 2 B 1 and 4 C 2 and 3 D 2 and 4

$5\text{ g}$ of four different fuels are set alight and placed under a beaker containing $50{\text{ cm}}^3$ of water. The temperature of the water is taken at the start and after five minutes. Which fuel releases the most energy?

Which changes increase the rate of reaction? 1 increasing the concentration of the reactants 2 increasing the particle size of a solid reactant 3 increasing the temperature A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Which reaction is reversible? A an iron nail rusting when left in moist air B limestone reacting with an acid to form carbon dioxide gas C magnesium burning in air to produce a white ash D white anhydrous copper(II) sulfate turning blue when water is added

The equation for the reaction between iron(III) oxide and carbon is shown. $$2{\mathrm{F}\mathrm{e}}_2{\mathrm{O}}_3+3\mathrm{C}\to 4\mathrm{F}\mathrm{e}+3{\mathrm{C}\mathrm{O}}_2$$ Which type of reaction does iron(III) oxide undergo? A reduction B precipitation C oxidation D combustion

Copper(II) chloride is made when copper(II) carbonate reacts with dilute hydrochloric acid. What are the other products in this reaction? A water and carbon dioxide B carbon dioxide only C water and hydrogen D hydrogen only

Rubidium is in Group I and strontium is in Group II of the Periodic Table. Which row describes the nature of rubidium oxide, ${\mathrm{R}\mathrm{b}}_2\mathrm{O}$, and strontium oxide, $\mathrm{S}\mathrm{r}\mathrm{O}$?

Magnesium sulfate is a soluble solid which is formed when insoluble magnesium oxide reacts with dilute sulfuric acid. Which method is used to prepare solid magnesium sulfate? A Excess sulfuric acid is reacted with magnesium oxide. The mixture is evaporated to dryness. B Excess sulfuric acid is reacted with magnesium oxide. The precipitate is filtered, washed and dried. C Sulfuric acid is reacted with excess magnesium oxide. The mixture is filtered and the filtrate is evaporated to dryness. D Sulfuric acid is reacted with excess magnesium oxide. The precipitate is filtered, washed and dried.

Q and R are elements in the same period of the Periodic Table. Q has 7 electrons in its outer shell and R has 2 electrons in its outer shell. Which statement about Q and R is correct? A Q is a metal and R is a non-metal. B Q and R have different numbers of electron shells. C R is found to the right of Q in the Periodic Table. D The proton number of R is less than the proton number of Q.

Which statement about alkali metals is correct? A Lithium is more dense than sodium. B Sodium is more reactive than potassium. C Sodium has a higher melting point than potassium. D They are in Group II of the Periodic Table.

Aqueous bromine is added to aqueous sodium iodide. $$\text{bromine}+\text{sodium iodide}\to \dots \dots 1\dots \cdots +\dots \dots 2\dots \dots$$ What are the products of this reaction?

Which row describes the properties of a transition element?

Which row describes the properties of argon?

Which row identifies the properties of zinc?

Uses of metals depend on their properties. Which property is necessary for the use given?

Which compounds both contribute to acid rain? A carbon monoxide and carbon dioxide B carbon monoxide and oxides of nitrogen C oxides of nitrogen and sulfur dioxide D sulfur dioxide and carbon dioxide

P, Q, R and S are metals. P reacts with dilute hydrochloric acid, forming hydrogen. Q reacts violently with water. R reacts with water to give hydrogen. S is formed by heating its oxide with carbon. Which row identifies the metals?

Which compound is formed when iron rusts? A anhydrous iron(II) oxide B anhydrous iron(III) oxide C hydrated iron(III) hydroxide D hydrated iron(III) oxide

Which reaction in the blast furnace releases heat energy? A $\mathrm{C}+{\mathrm{O}}_2\to {\mathrm{C}\mathrm{O}}_2$ B ${\mathrm{C}\mathrm{a}\mathrm{C}\mathrm{O}}_3\to \mathrm{C}\mathrm{a}\mathrm{O}+{\mathrm{C}\mathrm{O}}_2$ C ${\mathrm{C}\mathrm{O}}_2+\mathrm{C}\to 2\mathrm{C}\mathrm{O}$ D ${\mathrm{F}\mathrm{e}}_2{\mathrm{O}}_3+3\mathrm{C}\mathrm{O}\to 2\mathrm{F}\mathrm{e}+3{\mathrm{C}\mathrm{O}}_2$

A wax candle is made from a mixture of hydrocarbons. The candle is lit and placed in a gas jar along with a strip of cobalt(II) chloride test paper as shown. After a short time, the oxygen in the jar is used up and the candle flame goes out. Which substance does the cobalt(II) chloride paper identify? A carbon dioxide B carbon monoxide C sulfur dioxide D water

Urea, ${\mathrm{C}\mathrm{O}(\mathrm{N}\mathrm{H}}_2{)}_2$, is used as a fertiliser. Which element that plants need for improved plant growth is provided by urea? A carbon B hydrogen C nitrogen D oxygen

The percentage composition of gases on Neptune is shown.

Which statement about the atmospheres on Neptune and on the Earth is correct? A There is more helium on Neptune than oxygen on the Earth. B There is less methane on Neptune than carbon dioxide on the Earth. C There is less hydrogen on the Earth than on Neptune. D There is more helium on the Earth than on Neptune.

Which row shows the general formula for alkenes and for alcohols?

A molecule has the formula ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{C}\mathrm{l}$. What is its chemical name? A chloroethane B chloroethanol C chloroethene D chloromethanol

Which compound rapidly decolourises aqueous bromine? A ethane B ethanoic acid C ethanol D ethene

Compound Z has the molecular formula ${\mathrm{C}}_2{\mathrm{H}}_6\mathrm{O}$. Which statement about compound Z is correct? A Z is unsaturated. B Z is a carboxylic acid. C Z is formed by the reaction of ethane with steam. D Z is used as a fuel.

What is the formula of the salt formed when aqueous ethanoic acid reacts with calcium carbonate? A ${\mathrm{C}\mathrm{a}(\mathrm{C}\mathrm{H}}_3{\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H})}_2$ B ${\mathrm{C}\mathrm{a}(\mathrm{C}\mathrm{H}}_3{\mathrm{C}\mathrm{O}\mathrm{O})}_2$ C ${\mathrm{C}\mathrm{a}}_2{\mathrm{C}\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}$ D ${\mathrm{C}\mathrm{a}}_2{\mathrm{C}\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{O}$

Rock salt is a mixture of salt and sand. The method used to separate the sand from the salt is listed. step 1 Crush the rock salt, add to warm water and stir. step 2 Pour the mixture through a filter paper held in a funnel. step 3 Evaporate the water to crystallise the salt. Which statement about the method is correct? A The filtrate in step 2 is pure water. B The residue in step 2 is pure crystals of salt. C The solute is salt. D The solvent is a mixture of salt and water.

Chromatography is carried out on mixture Y and dyes E, F, G and H. The chromatogram is shown. Which dyes are present in mixture Y? A E and G B E and H C F and G D F and H

A fractionating column is used to separate the hydrocarbon fractions in petroleum by fractional distillation. Which row describes the properties of the fractions that condense at the top of the fractionating column?

When acid is added to salt X, a gas is produced which turns limewater milky. When sodium hydroxide is added to salt X, a gas is produced which turns litmus paper blue. What is X? A ${\mathrm{C}\mathrm{a}\mathrm{C}\mathrm{O}}_3$ B $({\mathrm{N}\mathrm{H}}_4{)}_2{\mathrm{C}\mathrm{O}}_3$ C ${\mathrm{N}\mathrm{H}}_4{\mathrm{N}\mathrm{O}}_3$ D ${\mathrm{Z}\mathrm{n}\mathrm{C}\mathrm{O}}_3$