Feb/March 2016

Two gas jars are arranged as shown. The lid is taken off and the gas jars are left standing. After a while, the contents of both gas jars turn brown. Which process makes this happen?

Diffusion

When concentrated hydrochloric acid undergoes electrolysis, gases P and Q are produced. Which gases are P and Q?

Electrolysis

Which substance would not be suitable for use as a fuel when heating water in a boiler?

Fuels

Which statement about reactions that release heat is incorrect?

Exothermic and endothermic reactions

Which changes make the rate of reaction faster?

Rate of reaction

Two reactions that involve water are illustrated below. X: anhydrous cobalt(II) chloride $\rightarrow$ hydrated cobalt(II) chloride Y: iron + oxygen + water $\rightarrow$ rust Which of these reactions can be reversed by heating?

Reversible reactions and equilibrium

Iron is obtained from iron oxide using carbon monoxide, as shown below. iron oxide + carbon monoxide $\rightarrow$ iron + carbon dioxide Which statement is correct?

Extraction of metals

Four separate solutions, W, X, Y and Z, are checked with Universal Indicator. Solution W produces green, X produces red, Y produces purple, and Z produces orange. Which solutions are acidic?

The characteristic properties of acids and bases

Methyl orange becomes red in the solution produced when substance R reacts with water. Which substance is R?

The characteristic properties of acids and bases

A salt is prepared by reacting an excess of an insoluble metal oxide with an acid. How is the extra metal oxide separated from the mixture?

Preparation of salts

A sample is warmed with aluminium foil in aqueous sodium hydroxide. A gas is given off that changes damp red litmus paper to blue. Which anion is present in the sample?

Identification of ions and gases

Which piece of apparatus is used to measure varying volumes of liquid during a titration?

Acid–base titrations

The element is a non-conductor of electricity and is present as diatomic molecules. In which part of the Periodic Table is the element located?

Group VII properties

In the Periodic Table, how does the metallic character of the elements change from left to right across a period?

Arrangement of elements

The elements in one group of the Periodic Table display these patterns. Which group do the elements belong to? 1. The element with the smallest proton number has the lowest reactivity. 2. Every element in the group produces basic oxides. 3. The density of the elements rises down the group. 4. The melting point of the elements falls down the group.

Group I properties

Which element belongs to the transition metals?

Transition elements

Uranium is a radioactive element, but it is also a typical metal. Which of the following is not a property of uranium?

Properties of metals

Which metal reacts with steam but does not react with cold water?

Reactivity series

Iron is obtained from hematite in the blast furnace. Hematite contains silicon(IV) oxide (sand) as an impurity. What substance reacts with this impurity to remove it?

Extraction of metals

Aircraft fuselages are frequently manufactured from aluminium. Which two properties of aluminium make it suitable for this application?

Uses of metals

The diagram illustrates how water is processed so that it becomes safe for drinking. What occurs in stage 2?

Water

Unpolluted air is made up of nitrogen, oxygen and trace amounts of other gases. The table does not include the noble gases. Which row gives the composition of dry, unpolluted air?

Elements, compounds and mixtures

Which technique is used to separate a mixture of sugar and glass?

Separation and purification

Which pollutant gas is formed when octane, $\text{C}_8\text{H}_{18}$, undergoes incomplete combustion?

Fuels

Fertilisers are applied to supply the three elements required to raise crop yield. Which two compounds would supply all three of these elements?

Fertilisers

Which statement gives a disadvantage of sulfur dioxide?

Air quality and climate

What is the reason for a farmer adding lime (calcium oxide) to soil?

The characteristic properties of acids and bases

What is fraction X called?

Fuels

Which pair of molecules are classed as hydrocarbons?

Formulae, functional groups and terminology

Which type of bond is absent from the structure of ethanol, $\text{CH}_3\text{CH}_2\text{OH}$?

Simple molecules and covalent bonds

Which change shown on the diagram includes combustion? Not all of the reaction products are displayed on the diagram.

Exothermic and endothermic reactions

Diagrams of three molecules are displayed. Which homologous series is absent?

Formulae, functional groups and terminology

Data for four hydrocarbons is given. Which statement is correct?

Formulae, functional groups and terminology

In which row are the substances classified correctly?

Elements, compounds and mixtures

Which structure is the one for a compound that, when dissolved in water, forms an acidic solution?

The characteristic properties of acids and bases

An element named Q has 4 electrons in its outer shell and 69 neutrons, and it conducts electricity. What is Q?

Atomic structure and the Periodic Table

Which statement gives the description of positive ions?

Ions and ionic bonds

The electronic structures of atoms X and Y are shown. X and Y combine to make a covalent compound. What formula does it have?

Simple molecules and covalent bonds

The compound magnesium nitrate has the formula $\text{Mg(NO}_3\text{)}_2$. What is the relative formula mass for magnesium nitrate?

Relative masses of atoms and molecules

The diagram is a cross-section that shows how aluminium and steel wires are arranged inside an electric power cable. Which metal wire conducts electricity better, and which metal wire has the larger mechanical strength?

Properties of metals

Two gas jars are arranged as shown. The lid is removed and the gas jars are left to stand. After some time, the contents of both gas jars are brown. Which process causes this to happen?

Diffusion

The electrolysis of concentrated hydrochloric acid is illustrated. Which statement explains what happens to the electrons during the electrolysis?

Electrolysis

Which reaction does not take place during the extraction of aluminium?

Extraction of metals

Which substance would not be suitable as a fuel for heating water in a boiler?

Fuels

Which row gives a description of an endothermic reaction?

Exothermic and endothermic reactions

A reversible reaction is represented below. $2\text{NO}_2(\text{g}) \rightleftharpoons \text{N}_2\text{O}_4(\text{g}) \qquad \Delta H = -58\,\text{kJ mol}^{-1}$ Which statement concerning an equilibrium mixture containing $\text{NO}_2$ and $\text{N}_2\text{O}_4$ is correct?

Reversible reactions and equilibrium

Which statement concerning catalysts in chemical reactions is incorrect?

Rate of reaction

Zinc is obtained from zinc blende by roasting it in air so that zinc oxide is formed. The zinc oxide is then heated with carbon to produce zinc. The equations for the reactions are shown. 1. $2\text{ZnS} + 3\text{O}_2 \rightarrow 2\text{ZnO} + 2\text{SO}_2$ 2. $\text{ZnO} + \text{C} \rightarrow \text{Zn} + \text{CO}$ Which statement concerning reactions 1 and 2 is not correct?

Extraction of metals

The diagram illustrates an energy level diagram for a reaction. From the diagram, it can be seen that the reaction is ......1...... . Raising the temperature increases the rate of reaction. One reason for this is that the ......2...... . Which words correctly fill gaps 1 and 2?

Exothermic and endothermic reactions

Concentrated hydrochloric acid is classed as a strong acid. What do the terms "strong" and "acid" mean?

The characteristic properties of acids and bases

Which oxide shows amphoteric properties?

Oxides

Which piece of apparatus is used to measure changing amounts of liquid in a titration?

Acid–base titrations

A salt is prepared by adding an excess of an insoluble metal oxide to an acid. How is the extra metal oxide separated from the mixture?

Preparation of salts

A substance is warmed with aluminium foil in aqueous sodium hydroxide. A gas is given off that changes damp, red litmus paper to blue. Which anion is contained in the substance?

Identification of ions and gases

An element does not conduct electricity and occurs as diatomic molecules. In which section of the Periodic Table is this element located?

Arrangement of elements

In the Periodic Table, in what way does the metallic character of elements change from left to right across a period?

Arrangement of elements

The elements in one group of the Periodic Table show these patterns. 1 The element with the smallest proton number is the least reactive. 2 Every element in the group forms basic oxides. 3 The density of the elements rises down the group. 4 The melting point of the elements falls down the group. Which group do these elements belong to?

Group I properties

Brass is an alloy made from two metals. Which row shows a correct use of the two metals used to make brass?

Alloys and their properties

Iron is obtained from hematite in a blast furnace. The hematite has silicon(IV) oxide (sand) present as an impurity. Which substance reacts with this impurity to eliminate it?

Extraction of metals

The reaction shown below is known as the ‘thermite reaction’. $2\text{Al} + \text{Fe}_2\text{O}_3 \rightarrow 2\text{Fe} + \text{Al}_2\text{O}_3$ Which pair of substances undergoes a similar reaction?

Redox

One way to prevent iron from rusting is to stop oxygen from reaching the metal surface. Which rust prevention method does not depend on this approach?

Corrosion of metals

The diagram illustrates the process used to treat water so that it becomes safe to drink. stage 1: reservoir → stage 2 → stage 3: chlorination → stage 4: drinking water What takes place at stage 2?

Water

A sample of green food colouring was separated into its individual colours by paper chromatography. The results are shown. What is the $R_f$ value of the blue spot?

Chromatography

When petrol burns in a car engine, nitrogen monoxide is formed. The exhaust gases from the car engine are sent through a catalytic converter. Inside the catalytic converter, nitrogen monoxide reacts with carbon monoxide to produce nitrogen and carbon dioxide. Which statement is incorrect?

Redox

Which pollutant gas may be formed as a consequence of the incomplete combustion of octane, $\text{C}_8\text{H}_{18}$?

Air quality and climate

Fertilisers are used to supply the three elements needed to raise the yield of crops. Which two compounds would supply all three of these elements?

Fertilisers

Which property is shown by concentrated sulfuric acid but not by dilute sulfuric acid?

The characteristic properties of acids and bases

For what reason would a farmer add lime (calcium oxide) to the soil?

The characteristic properties of acids and bases

What is fraction X called?

Fuels

Which of the compounds listed are alkanes? Compound W: $\text{C}_4\text{H}_{10}$ Compound X: $\text{C}_5\text{H}_{10}$ Compound Y: $\text{C}_6\text{H}_{12}$ Compound Z: $\text{C}_6\text{H}_{14}$

Alkanes

The statements here refer to the alcohol homologous series. All alcohols share the same ......1...... formula. Alcohols show ......2...... chemical properties because they contain the same ......3...... . As the number of carbon atoms rises, the melting points of the alcohols ......4...... . Which words correctly fill gaps 1-4?

Formulae, functional groups and terminology

Which structure shows a compound that dissolves in water to produce an acidic solution?

Carboxylic acids

The diagram shows part of an addition polymer. What is the structure of the monomer from which this polymer is made?

Polymers

Which row shows the substances classified correctly?

Elements, compounds and mixtures

Which of the following statements about polymers is correct?

Polymers

Which molecule is made up entirely of single covalent bonds?

Simple molecules and covalent bonds

Which structure shows the sodium chloride lattice?

Ions and ionic bonds

X and Y are isotopes of one element. Which statement is correct?

Isotopes

What quantities of chemicals will react exactly, with no reactants remaining?

The mole and the Avogadro constant

Magnesium burns in air to produce magnesium nitride. Magnesium nitride is an ionic compound. What is the formula for magnesium nitride?

Ions and ionic bonds

The diagram presents a section of the Periodic Table. Groups I, II, III, IV, V, VI, VII and VIII are included. The elements shown are Li in Group I; Ti, Cr, Fe, Cu and Zn among the transition metals; C, N, O, F, Ne; Al, Si, P, S, Cl, Ar; Ge, Br, Kr; Sn, I, Xe; Pb.

Atomic structure and the Periodic Table

The apparatus shown can be used to electrolyse molten potassium bromide. It has graphite electrodes dipped into the molten potassium bromide.

Electrolysis

A number of metals react with cold water or with steam.

Rate of reaction

The diagrams below show the structures of sodium chloride and nitrogen.

Simple molecules and covalent bonds

Which metal is the best choice for the base of a pan used for cooking food? Use information in the table to give reasons for your answer.

Uses of metals

Citric acid occurs in lemon juice, and it displays the usual properties of an acid.

Carboxylic acids

Rhenium is one of the metals.

Properties of metals

The table beneath shows information about particles. Fill in the missing entries. The first row has already been completed for you.

Elements, compounds and mixtures

Rubidium, Rb, belongs to Group I. Its physical and chemical behaviour is similar to that of the other Group I elements.

Group I properties

Carbon dioxide and silicon(IV) oxide are oxides belonging to Group IV elements.

Giant covalent structures

With manganese(IV) oxide acting as the catalyst, hydrogen peroxide, $\text{H}_2\text{O}_2$, breaks down to form water and oxygen. $2\text{H}_2\text{O}_2(aq) \rightarrow 2\text{H}_2\text{O}(l) + \text{O}_2(g)$

Rate of reaction

This question concerns compounds of nitrogen.

Fertilisers

Iron pyrite, $\text{FeS}_2$, is called Fool’s Gold since it is a shiny yellow solid that looks similar to gold. Iron pyrite is an ionic compound. Gold is a metallic element.

Ions and ionic bonds

Alkanes and alkenes are both types of hydrocarbons.

Formulae, functional groups and terminology