Feb/March 2017

A bottle containing aqueous ammonia is left on a table in one corner of the laboratory. The stopper is taken out and, after a few minutes, every student in the room is able to detect the smell of ammonia. Which process takes place?

Diffusion

Ammonium chloride is put into $100\,\text{cm}^3$ of water. The temperature falls from $25^\circ\text{C}$ to $20^\circ\text{C}$. What type of reaction takes place?

Exothermic and endothermic reactions

The energy change for an exothermic reaction is represented in the diagram below. Which reactions would this diagram fit?

Exothermic and endothermic reactions

The diagram illustrates the apparatus used to determine the rate of a chemical reaction. For which reaction can this apparatus be used to measure the rate?

Rate of reaction

Copper(II) carbonate is reacted with dilute sulfuric acid. $\text{CuCO}_3(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{CuSO}_4(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$ The rate of this reaction may be altered by changing the conditions. Which changes are certain to speed up this chemical reaction?

Rate of reaction

In which reaction is the first substance in the equation oxidised?

Redox

The equation showing the action of heat on hydrated sodium carbonate is given below. $\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}(s) \rightleftharpoons \text{Na}_2\text{CO}_3(s) + 10\text{H}_2\text{O}(g)$ Four students have each made a statement about this reaction. Which students’ statements are correct?

Reversible reactions and equilibrium

Which reaction counts as a neutralisation reaction?

The characteristic properties of acids and bases

Elements W and X are metals. Elements Y and Z are non-metals. When the oxides of W, X, Y and Z are each added to water, they all produce solutions. Which statement is correct?

The characteristic properties of acids and bases

A student is given an unknown solution. Which two tests give evidence that the solution is copper(II) sulfate?

Identification of ions and gases

The diagram outlines the stages used to prepare a salt. Which salt is made by this method?

Preparation of salts

A student is carrying out chromatography on a coloured mixture. At which position should the student apply the coloured mixture?

Chromatography

Which property of the elements rises from left to right across a period of the Periodic Table?

Arrangement of elements

The noble gases are placed in Group VIII of the Periodic Table. Which statement gives the reason why noble gases do not react?

Noble gases

Which compound is produced from elements that all lie in the same period?

Arrangement of elements

A section of the Periodic Table is shown. Which element acts as a catalyst?

Transition elements

Which of the following statements is true for all metals?

Properties of metals

Two experiments are performed. In experiment 1, copper is heated in steam. In experiment 2, copper(II) oxide is heated with carbon. Which row gives the outcomes for experiments 1 and 2?

Redox

Which metal is commonly combined with a non-metallic element to make an alloy?

Alloys and their properties

Steel is produced by adding ..... 1 ..... into molten iron so that ..... 2 ..... is removed from the iron. Stainless steel is ..... 3 ..... resistant to corrosion than mild steel. Which words fit gaps 1, 2 and 3?

Alloys and their properties

Water is introduced to hydrated copper(II) sulfate. What colour change is observed?

Physical and chemical changes

Two reactions, X and Y, produce carbon dioxide. $\text{CH}_4 \xrightarrow{X} \text{CO}_2 \xleftarrow{Y} \text{CaCO}_3$ What types of reaction are X and Y?

Physical and chemical changes

The diagrams display liquids in a burette and a measuring cylinder. Which row gives the correct readings for the burette and the measuring cylinder?

Experimental design

The diagram shows an experiment that is used to determine the percentage of oxygen in $150\,\text{cm}^3$ of polluted air. The apparatus is then left for one week. After this period, the gas volume in the measuring cylinder is $122\,\text{cm}^3$. What is the percentage of oxygen, to the nearest whole number, in the polluted air?

Air quality and climate

Ammonia is made when a mixture of ammonium chloride and substance X is heated. Identify substance X.

The characteristic properties of acids and bases

Which row is correct for carbon dioxide as well as methane?

Simple molecules and covalent bonds

Which of the following statements about sulfur dioxide are correct?

Oxides

A student did two experiments. experiment 1: The student heated a limestone sample very strongly. A white powder was formed. experiment 2: The white powder from experiment 1 was allowed to cool. The student then added a little cold water to the powder. Large amounts of steam were given off. Which statement is incorrect?

Exothermic and endothermic reactions

Which substance has a principal constituent that contains just one carbon atom in each molecule?

Formulae, functional groups and terminology

The table gives the composition of four different kinds of petroleum. Which type of petroleum is most suitable for use in the motor vehicle industry?

Fuels

Ethanol is a fuel used in cars. It can be manufactured from petroleum. $\text{C}_4\text{H}_{10} \rightarrow \text{C}_2\text{H}_4 + \text{C}_2\text{H}_6$ (cracking) $\text{C}_2\text{H}_4 + \text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_5\text{OH}$ (producing ethanol) $\text{C}_2\text{H}_5\text{OH} + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 3\text{H}_2\text{O}$ (burning) How many different homologous series are represented by the compounds in these equations?

Formulae, functional groups and terminology

Ethanol can be made from either ethene or sugar. For each route, which type of chemical reaction is involved?

Alcohols

Which kind of hydrocarbon reacts quickly with aqueous bromine, and what colour change does the aqueous bromine undergo?

Alkenes

The diagram illustrates a method of cleaning muddy water. Which purification process is being shown?

Separation and purification

The diagram illustrates the structure of a key product. This product is made by ......1...... of an ......2...... . Which words fill gaps 1 and 2?

Polymers

Which noble gas has the same electronic structure as an atom of the aluminium ion, $\text{Al}^{3+}$?

Ions and ionic bonds

A covalent molecule $M$ has a total of four shared electrons. Identify $M$.

Simple molecules and covalent bonds

The three substances below show these properties. • $X$ carries electric current in the solid state and also after melting. • $Y$ dissolves in water, and the resulting solution carries electric current. • $Z$ carries electric current only after it has been melted. What are $X$, $Y$ and $Z$?

Ions and ionic bonds

Caffeine is a stimulant present in coffee. Which formula is the one that represents caffeine?

Formulae, functional groups and terminology

Four substances undergo electrolysis. The substances are concentrated aqueous sodium chloride, concentrated hydrochloric acid, molten lead(II) bromide and molten sodium oxide. Which statement about these electrolysis reactions is correct?

Electrolysis

In the apparatus illustrated, a gas is given off at point Q. Which gas makes the damp Universal Indicator paper change colour most rapidly?

The characteristic properties of acids and bases

The diagram illustrates the electrolysis of aqueous copper(II) sulfate. Which statement is correct?

Electrolysis

Four solutions are electrolysed separately. In which two experiments is a colourless gas released at the anode?

Electrolysis

Ammonia is produced when nitrogen reacts with hydrogen in the presence of an iron catalyst. This reaction is exothermic. The reaction equation is given below. $\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3$. The bond energies are listed in the table. What is the energy released in this reaction?

Exothermic and endothermic reactions

The energy level diagram for the reaction in which P and Q react to produce R and S is shown. Which row states the energy changes involved and the reaction type?

Exothermic and endothermic reactions

Copper(II) carbonate is allowed to react with dilute sulfuric acid. $\text{CuCO}_3(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{CuSO}_4(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$. The speed of the reaction may be altered by changing the conditions. Which changes will always make this chemical reaction faster?

Rate of reaction

Which reaction is not influenced by the presence of light?

Rate of reaction

The equation for the reversible reaction of hydrogen with iodine to produce hydrogen iodide is given. The colours of the reactants and products are shown. $\text{H}_2(g) + \text{I}_2(g) \rightleftharpoons 2\text{HI}(g)$. The forward reaction releases heat. Which statement is correct?

Reversible reactions and equilibrium

Chlorine removes bromine from potassium bromide solution. $\text{Cl}_2 + 2\text{KBr} \rightarrow 2\text{KCl} + \text{Br}_2$. Which substance acts as the oxidising agent in this reaction?

Redox

Beryllium oxide reacts with sulfuric acid and with aqueous sodium hydroxide. What kind of oxide is beryllium oxide?

Oxides

A student carries out an investigation on two acids W and X. Equal volumes of W and X are reacted separately with excess magnesium. The student records these observations. 1 Hydrogen gas is produced more quickly with W than with X. 2 The final volume of hydrogen gas produced is the same for both acids. Which statement accounts for these observations?

Rate of reaction

The diagrams display liquids in a burette and a measuring cylinder. Which row gives the correct readings for the burette and the measuring cylinder?

Experimental design

A student is provided with an unknown solution. Which two tests give evidence that the solution is copper(II) sulfate?

Identification of ions and gases

The diagram illustrates the stages involved in preparing a salt. Which salt is made using this method?

Preparation of salts

Which property of elements rises as you move across a period of the Periodic Table?

Arrangement of elements

Magnesium, calcium, strontium and barium are Group II elements. The elements in Group II show the same patterns as the Group I elements. Which of the following statements about Group II elements are correct?

Arrangement of elements

The noble gases are placed in Group VIII of the Periodic Table. Which statement explains the reason noble gases do not react?

Noble gases

A portion of the Periodic Table is shown. Which element acts as a catalyst?

Transition elements

Which statement is true for all metals?

Properties of metals

Which substance gives sulfur dioxide when it is roasted in air?

Extraction of metals

When heated with a Bunsen burner, which metal carbonate does not give off carbon dioxide?

Group I properties

Two experiments are performed. In experiment 1, copper is heated with steam. In experiment 2, copper(II) oxide is heated with carbon. Which row gives the description of what occurs in experiments 1 and 2?

Reactivity series

The diagram illustrates how muddy water can be purified. Which purification process is shown for the muddy water?

Separation and purification

Which two gases are separated from liquid air by fractional distillation?

Separation and purification

A setup for determining the percentage of oxygen in $150\,\text{cm}^3$ of polluted air is shown. The apparatus is then left for one week. After this period, the gas volume in the measuring cylinder is $122\,\text{cm}^3$. What percentage of oxygen is present in the polluted air, correct to the nearest whole number?

Air quality and climate

Two reactions, X and Y, form carbon dioxide. $\text{CH}_4 \xrightarrow{X} \text{CO}_2 \xleftarrow{Y} \text{CaCO}_3$ What kinds of reaction are X and Y?

Physical and chemical changes

The ions found in ammonium sulfate are produced from the outputs of the Contact and Haber processes. A catalyst is used in both of these processes. Which row is correct?

Ions and ionic bonds

The table presents the make-up of four different petroleum types. Which petroleum type is most suitable for the motor vehicle industry?

Fuels

Which reaction involving ethene is not classified as an addition reaction?

Alkenes

Ethanol is used as a fuel in cars. It can be produced from petroleum. $\text{C}_4\text{H}_{10} \rightarrow \text{C}_2\text{H}_4 + \text{C}_2\text{H}_6$ (cracking) $\text{C}_2\text{H}_4 + \text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_5\text{OH}$ (producing ethanol) $\text{C}_2\text{H}_5\text{OH} + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 3\text{H}_2\text{O}$ (burning) How many homologous series are represented by the compounds in these equations?

Formulae, functional groups and terminology

Ethanol can be made from ethene or from sugar. What kind of chemical reaction is involved in each of these two cases?

Alcohols

An organic compound has the structural formula shown below. $\text{CH}_3\text{CH}_2\text{COOCH}_3$ What is this compound called?

Naming organic compounds

The diagram illustrates the arrangement of a significant product. This product is made by …… 1 …… of an …… 2 …… . Which words fill gaps 1 and 2?

Polymers

Which statement accounts for why isotopes of an element show the same chemical properties?

Isotopes

Which two compounds react together to produce a condensation polymer?

Polymers

The formulae for some ions are given below. In which row is the formula incorrect?

Ions and ionic bonds

Diamond and silicon(IV) oxide each have giant structures. Which statements are correct?

Giant covalent structures

Which of the following statements about metals is correct?

Properties of metals

Hydrazine is a gas with molecular formula $\text{N}_2\text{H}_4$. When hydrazine burns in air, nitrogen gas and steam are formed. $\text{N}_2\text{H}_4(g) + \text{O}_2(g) \rightarrow \text{N}_2(g) + 2\text{H}_2\text{O}(g)$. Which statements are correct?

Redox

When copper(II) carbonate is heated, it decomposes to produce copper(II) oxide and carbon dioxide gas. The reaction equation is given as shown. $\text{CuCO}_3 \rightarrow \text{CuO} + \text{CO}_2$. A mass of $31.0\,\text{g}$ of copper(II) carbonate is heated until every part of the test-tube contents changes from green to black. The mass of copper(II) oxide obtained is $17.5\,\text{g}$. Calculate the percentage yield.

The mole and the Avogadro constant

Use the list of elements below to answer the questions that follow. aluminium argon carbon lithium magnesium nickel nitrogen oxygen sulfur Each element may be used once, more than once, or not at all.

Atomic structure and the Periodic Table

The diagram depicts a blast furnace used to extract iron. Text on the diagram: mixture of iron ore, coke and limestone (calcium carbonate); slag; molten iron.

Extraction of metals

Hydrocarbons that burn in car engines react with air to produce a blend of gases. The table gives the proportions of the gases in the mixture leaving a car exhaust.

Alkanes

Ammonia is made by reacting nitrogen with hydrogen at high temperature and pressure. $\text{N}_2 + 3\text{H}_2 \rightleftharpoons 2\text{NH}_3$

Reversible reactions and equilibrium

Lavandulol is a compound present in lavender flowers. Its structure is displayed.

Formulae, functional groups and terminology

Chlorine and sodium hydroxide are made by electrolysing concentrated aqueous sodium chloride.

Electrolysis

Metals show characteristic properties.

Reactivity series

Five organic compounds have these displayed structures. Compound A has a four-carbon straight chain with only single bonds, and every carbon is attached to hydrogen atoms. Compound B has four carbon atoms with a carbon-carbon double bond between the second and third carbons, with hydrogen atoms attached. Compound C has four carbon atoms with a carbon-carbon double bond between the first and second carbons, with hydrogen atoms attached. Compound D has two carbon atoms joined by a single bond, and each carbon is bonded to a bromine atom and hydrogen atoms. Compound E has a chain of three carbon atoms, with bromine atoms attached to the first and last carbon atoms and hydrogen atoms attached.

Naming organic compounds

Silver dichromate, $\text{Ag}_2\text{Cr}_2\text{O}_7$, is a red insoluble salt. It may be prepared by adding silver nitrate solution to ammonium dichromate solution. The reaction is represented by the equation shown below. $2\text{AgNO}_3(aq) + (\text{NH}_4)_2\text{Cr}_2\text{O}_7(aq) \rightarrow 2\text{NH}_4\text{NO}_3(aq) + \text{Ag}_2\text{Cr}_2\text{O}_7(s)$

Separation and purification

Nitryl chloride, $\text{NO}_2\text{Cl}$, reacts with nitric oxide, NO, and the forward change gives out heat. $\text{NO}_2\text{Cl}$(g) + NO(g) $\rightleftharpoons$ $\text{NO}_2$(g) + NOCl(g) This reaction is able to establish equilibrium.

Reversible reactions and equilibrium