Feb/March 2021

For which changes do the particles become more widely spaced? $\text{gas} \xrightleftharpoons[\,Y\,]{\,W\,} \text{liquid} \xrightleftharpoons[\,Z\,]{\,X\,} \text{solid}$

Solids, liquids and gases

A compound is given by the formula $\text{XF}_2$ and has a relative mass of 70. Which element is X?

Relative masses of atoms and molecules

The diagram illustrates part of an overhead power cable. Which statement explains the reason a certain material is chosen?

Uses of metals

Three substances are electrolysed with inert electrodes. Which of these substances gives hydrogen at the negative electrode?

Electrolysis

Which row identifies an endothermic reaction?

Exothermic and endothermic reactions

Fuels give out heat energy as they burn. Which substances are used as fuels?

Fuels

When zinc carbonate is added to dilute hydrochloric acid, change M occurs. When carbon is heated together with copper(II) oxide, change N occurs. Which row gives the correct description of changes M and N?

The characteristic properties of acids and bases

The apparatus illustrated is used to determine the rate of a reaction. Which equation shows a reaction whose rate can be measured with this apparatus?

Rate of reaction

P is a hydrated metal salt that is blue in colour. On heating P, water is released and solid Q remains. R is a hydrated metal salt that is pink in colour. On heating R, water is released and solid S remains. Which row states the name of P and the colour of S?

Transition elements

What property is exhibited by the alkali sodium hydroxide?

The characteristic properties of acids and bases

A section of the Periodic Table is shown. Which element produces an acidic oxide?

Oxides

Fractional distillation is used to separate gases from liquid air. The boiling points of four gases are given below. Which gas is monoatomic and also a liquid at $-200\,^{\circ}\text{C}$?

Solids, liquids and gases

If aqueous sodium hydroxide is introduced into a solution containing a metal ion, a grey-green precipitate is produced, and in excess it dissolves to give a dark green solution. Which metal ion is present?

Identification of ions and gases

Which statements describe the Periodic Table? 1 The elements are ordered by their nucleon number. 2 The elements are ordered by their proton number. 3 It is used to predict the properties of elements.

Atomic structure and the Periodic Table

Which row indicates how the properties of the Group I elements change as you go down the group?

Group I properties

Copper is classified as a transition element. Two copper compounds are copper(II) oxide and copper(II) carbonate. Which row correctly describes these two compounds?

Ions and ionic bonds

Beryllium, the metal, does not react with cold water. It does react with hydrochloric acid, but it cannot be obtained from its ore by reduction with carbon. In the reactivity series, where is beryllium placed?

Reactivity series

Pure iron is a metal that is soft. When small amounts of tungsten are added, it forms a hard alloy named tungsten steel. Which of the statements are correct? 1 Pure iron is a transition element. 2 The particles in pure iron are arranged in ordered layers. 3 Tungsten steel is a compound.

Alloys and their properties

Which row gives the description of magnesium?

Arrangement of elements

The four equations below are given. 1 $\text{C} + \text{O}_2 \rightarrow \text{CO}_2$ 2 $\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2$ 3 $\text{SiO}_2 + 2\text{CO} \rightarrow \text{Si} + 2\text{CO}_2$ 4 $\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$ Which equations show reactions that occur during the extraction of iron from hematite?

Extraction of metals

Copper is used in the making of saucepans. Which properties of copper make it suitable for this use? 1 Copper has a fairly high melting point. 2 Copper has a low density. 3 Copper is a good conductor of electricity. 4 Copper is a good conductor of heat.

Properties of metals

Which pollutants lead to the erosion of buildings and statues? 1 carbon monoxide gas 2 oxides of nitrogen gases 3 sulfur dioxide gas

Air quality and climate

Impurities alter the melting and boiling points of substances. Sodium chloride is added to a sample of pure water. How does adding sodium chloride affect the melting point and the boiling point of the water?

Solids, liquids and gases

Which pair of chemical compounds could be used to make the fertiliser shown?

Fertilisers

X is formed when petrol undergoes complete combustion in air. What is X?

Fuels

Which substance is used to bleach paper during its manufacture?

Group VII properties

State one industrial use of calcium carbonate.

Elements, compounds and mixtures

Which substance is produced when calcium carbonate undergoes thermal decomposition?

Oxides

The pie chart shows the composition of natural gas. Which sector shows methane?

Elements, compounds and mixtures

Which fraction obtained from petroleum serves as jet fuel?

Fuels

A hydrocarbon has the formula $\text{C}_x\text{H}_y$. Its complete combustion equation is given below. $\text{C}_x\text{H}_y + 8\text{O}_2 \rightarrow 5\text{CO}_2 + 6\text{H}_2\text{O}$ What are the values of $x$ and $y$?

Formulae

Pentane is an alkane, whereas pentene is an alkene. What is seen when bromine water is added to a sample of each compound?

Alkenes

Molecule 1 is changed by a process to form molecule 2. molecule 1 $\xrightarrow{\text{process}}$ molecule 2 Which row gives the correct descriptions of the molecules and the process?

Formulae, functional groups and terminology

The apparatus for separating a mixture of sand, methanol and ethanol is shown. Which row correctly names the labels on the diagrams?

Separation and purification

Which substance is made up of long-chain molecules and forms part of food?

Carboxylic acids

A neutral atom, J, has 45 neutrons and 35 electrons. Which row shows the correct information for atom J?

Isotopes

Lithium and fluorine combine to make lithium fluoride. A student records three claims about this reaction. 1. Lithium atoms give up an electron as they react. 2. Each fluoride ion contains one more electron than a fluorine atom. 3. Lithium fluoride is a mixture of elements. Which claims are correct?

Ions and ionic bonds

Which is the correct definition of isotopes?

Isotopes

In which molecule are all of the outer-shell electrons from each atom involved in forming covalent bonds?

Simple molecules and covalent bonds

What is the balanced chemical equation for the reaction of calcium with water?

Reactivity series

Which row correctly describes a change of state?

Solids, liquids and gases

A compound is given by the formula $\text{XF}_2$ and has a relative mass of 70. Which element is X?

Relative masses of atoms and molecules

The diagram shows part of an overhead power cable. Which statement gives the reason for using a particular material?

Uses of metals

In the electrolysis of dilute sulfuric acid, hydrogen gas is produced at the cathode. What is the ionic half-equation for this reaction?

Electrolysis

Which row gives the description of an endothermic reaction?

Exothermic and endothermic reactions

The equation below represents the complete combustion of methane. $\text{CH}_4\text{(g)} + 2\text{O}_2\text{(g)} \rightarrow \text{CO}_2\text{(g)} + 2\text{H}_2\text{O( g)}$ The bond energies are listed in the table. What is the energy change for this reaction?

Exothermic and endothermic reactions

Fuel cells that use hydrogen can be used to power cars. Which of the following statements about a fuel cell are correct?

Hydrogen–oxygen fuel cells

The apparatus illustrated is used for measuring the rate of a reaction. Which equation shows a reaction for which this apparatus can be used to measure the rate?

Rate of reaction

P is a hydrated metal salt that is blue-coloured. When P is heated, water is released, and solid Q is left behind. R is a hydrated metal salt that is pink-coloured. When R is heated, water is released, and solid S is left behind. Which row gives the identity of P and the colour of S?

Transition elements

Magnesium reacts with copper(II) oxide to form magnesium oxide and copper. Which substance acts as the oxidising agent in this reaction?

Redox

A section of the Periodic Table is shown. Which element produces an acidic oxide?

Arrangement of elements

Liquid air is divided into its gases by fractional distillation. The boiling points of four gases are given. Which gas is monoatomic and also a liquid at $-200\,^{\circ}\text{C}$?

Noble gases

After aqueous sodium hydroxide is introduced into a solution containing a metal ion, a grey-green precipitate is produced, and this then dissolves in excess to give a dark green solution. What is the identity of the metal ion?

Identification of ions and gases

Which of the following statements about strong acids are correct?

The characteristic properties of acids and bases

Metal X combines with non-metal Y to produce an ionic compound having the formula $\text{X}_2\text{Y}$. Which of the following statements are correct?

Ions and ionic bonds

The table shows some properties of the elements in Group IV. Which row correctly describes the properties of silicon?

Arrangement of elements

The metal beryllium shows no reaction with cold water. It does react with hydrochloric acid, but carbon cannot be used to extract it from its ore. At what position in the reactivity series is beryllium placed?

Reactivity series

What is the purpose of cryolite in the extraction of aluminium from bauxite?

Extraction of metals

Which of the following statements concerning the uses of metals are correct?

Uses of metals

Which row shows the reactions of magnesium hydroxide and magnesium oxide?

Oxides

These are the properties of an element. Its melting point is $3414\,^{\circ}\text{C}$. Certain compounds it forms act as catalysts. It shows variable oxidation states. In which part of the Periodic Table is the element located?

Transition elements

Petrol is burned inside a car engine, creating waste gases that escape from the vehicle's exhaust. One of these waste gases is an oxide of nitrogen. Which statement explains how this oxide of nitrogen is produced?

Oxides

Two food colourings, X and Y, are examined by chromatography. Three pure dyes, 1, 2 and 3, are also examined. The chromatogram is shown. Which of the following statements are correct?

Chromatography

Which pair of chemical compounds could be used to make the fertiliser shown?

Fertilisers

Which process does not result in carbon dioxide being produced?

Air quality and climate

Which substance is used for bleaching during paper manufacture?

Group VII properties

For what industrial purpose is calcium carbonate used?

Elements, compounds and mixtures

Propane reacts with chlorine. Which row gives a condition needed for this reaction and identifies the type of reaction?

Alkanes

The pie chart shows the composition of natural gas. Which section corresponds to methane?

Elements, compounds and mixtures

Which statement describes how ethene reacts with steam?

Alkenes

A hydrocarbon has the formula $C_xH_y$. Its complete combustion is represented by the equation below. $C_xH_y + 8O_2 \rightarrow 5CO_2 + 6H_2O$ What are the values of $x$ and $y$?

Formulae, functional groups and terminology

The ester has the formula $CH_3CH_2CH_2COOCH_2CH_2CH_3$. Which acid and which alcohol combine to form this ester?

Formulae, functional groups and terminology

Molecule 1 is changed into molecule 2 by a process. Which row identifies the molecules and the process?

Formulae, functional groups and terminology

Which statement correctly describes the atoms of every carbon isotope?

Isotopes

Which structure is used to show a protein?

Polymers

Which diagram shows the structure of silicon(IV) oxide?

Giant covalent structures

Lithium and fluorine combine to make lithium fluoride. A student records three statements about this reaction. Which of the statements are correct?

Ions and ionic bonds

How many electrons take part in the formation of covalent bonds in a molecule of methanol, $\text{CH}_3\text{OH}$?

Simple molecules and covalent bonds

Magnesium oxide melts at a high temperature. Carbon dioxide melts at a low temperature. Which row shows the attractive forces that are broken when these compounds are melted?

Simple molecules and covalent bonds

The ionic half-equation for oxygen being produced in the electrolysis of aluminium oxide is given below. $x\text{O}^{2-} \rightarrow \text{O}_2 + y\text{e}^-$ What values do $x$ and $y$ have?

Electrolysis

The diagram displays part of the Periodic Table. Answer the following questions using only the symbols of the elements shown in the diagram. Each symbol may be used once, more than once, or not at all.

Atomic structure and the Periodic Table

The table gives the masses of selected ions in a $1000\,\text{cm}^3$ sea water sample.

Ions and ionic bonds

The table presents a few properties of four halogens.

Group VII properties

A student examines the reaction between magnesium powder and dilute hydrochloric acid. Magnesium is present in excess. $\text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2$ The reaction rate can be determined by tracking the rise in hydrogen volume with time. The graph shows the results.

Rate of reaction

This question concerns sulfur and compounds of sulfur.

Elements, compounds and mixtures

The structure of compound A is displayed.

Formulae, functional groups and terminology

Sodium is made by electrolysis.

Electrolysis

Aqueous ammonia behaves as an alkali.

The characteristic properties of acids and bases

The table sets out the numbers of protons, neutrons and electrons for particles A to I.

Isotopes

The substances listed below are gases at room temperature and pressure. hydrogen nitrogen oxygen chlorine

Diffusion

The question concerns ammonia.

Reversible reactions and equilibrium

A student aimed to produce some zinc chloride crystals and carried out the procedure below. step 1 Add excess zinc powder to dilute hydrochloric acid so aqueous zinc chloride is formed. step 2 Remove any unreacted zinc powder from the aqueous zinc chloride. step 3 Heat the solution until it becomes saturated. step 4 Let the saturated solution cool, then collect the crystals that appear.

Preparation of salts

The table lists the names or structures of organic compounds P to U.

Alkenes

Polymers are giant molecules formed from many smaller molecules.

Polymers