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1

The diagram represents, for a given temperature, the Boltzmann distribution of the kinetic energies of the molecules in a mixture of two gases that react together. The activation energy for the reaction, Ea , is marked. molecular energy proportion of molecules with a given energy Ea The dotted curves below show the Boltzmann distribution for the same reaction at a higher temperature. On these diagrams, H represents the activation energy at the higher temperature. Which diagram is correct?

8. Reaction kinetics  →  8.2. Effect of temperature on reaction rates and the concept of activation energy

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2

In the ideal gas equation, pV = nRT, what are the units of n and T ?

4. States of matter  →  4.1. The gaseous state: ideal and real gases and \( pV = nRT \)

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3

The reaction between acidified dichromate(ions, Cr2O7 2–, and aqueous Fe2+ ions results in the dichromate(ions being reduced to Cr3+ ions. What is the correct equation for this reaction?

11. Group 17  →  11.3. Some reactions of the halide ions

2. Atoms, molecules and stoichiometry  →  2.3. Formulas

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4

Sodium azide, NaN3 is an explosive used to inflate airbags in cars when they crash. It consists of positive sodium ions and negative azide ions. What are the numbers of electrons in the sodium ion and the azide ion?

1. Atomic structure  →  1.1. Particles in the atom and atomic radius

1. Atomic structure  →  1.3. Electrons, energy levels and atomic orbitals

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5

The 68Ge isotope is medically useful because it undergoes a natural radioactive process to give an isotope of a different element, 68X, which can be used to detect tumours. This transformation of 68Ge occurs when an electron enters the nucleus and changes a proton into a neutron. Which statement about the composition of an atom of 68X is correct?

1. Atomic structure  →  1.2. Isotopes

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6

Histamine is produced in the body to help fight infection. Its shape allows it to fit into receptors which expand blood vessels. H C N H H C C C C N N H H H H z H H y x histamine What are the bond angles x, y and z in histamine, from the smallest to the largest?

3. Chemical bonding  →  3.5. Shapes of molecules

13. An introduction to AS Level organic chemistry  →  13.3. Shapes of organic molecules; σ and π bonds

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7

The approximate percentage composition of the atmospheres on four different planets is given in the table below. Which mixture of gases has the greatest density?

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8

An important reaction in the manufacture of nitric acid is the catalytic oxidation of ammonia. 4NH3+ 5O24NO+ 6H2OFor every mole of O2 that reacts in this way, 181.8 kJ of energy are released. A factory makes 2.50 × 105 mol of NO every day. How much energy, in kJ, is released every day?

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

2. Atoms, molecules and stoichiometry  →  2.4. Reacting masses and volumes (of solutions and gases)

5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)

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9

Sodium chromate(, Na2CrO4, is manufactured by heating chromite, FeCr2O4, with sodium carbonate in an oxidising atmosphere. Chromite contains Cr2O4 2– ions. 2FeCr2O4 + 4Na2CO3 + 3 2 1 O2 → 4Na2CrO4 + Fe2O3 + 4CO2 What happens in this reaction?

11. Group 17  →  11.4. The reactions of chlorine

9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3

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10

The table shows the partial pressures in an equilibrium mixture formed by the Haber process. 3H2+ N22NH3What is the numerical value of the equilibrium constant, Kp, for this reaction?

7. Equilibria  →  7.1. Chemical equilibria: reversible reactions, dynamic equilibrium

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11

An autocatalytic reaction is a reaction in which one of the products catalyses the reaction. Which curve would be obtained if the rate of an autocatalytic reaction is plotted against time?

8. Reaction kinetics  →  8.1. Rate of reaction

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12

1.15 g of a metallic element needs 300 cm3 of oxygen for complete reaction, at 298 K and 1 atm pressure, to form an oxide which contains O2– ions. What could be the identity of this metallic element?

9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3

10. Group 2  →  10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds

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13

The diagram shows the melting points of eight elements with consecutive atomic numbers. Which element could be sodium?

9. The Periodic Table: chemical periodicity  →  9.1. Periodicity of physical properties of the elements in Period 3

9. The Periodic Table: chemical periodicity  →  9.3. Chemical periodicity of other elements

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14

The properties of chlorine, bromine and their compounds are compared. Which property is smaller for chlorine than for bromine?

11. Group 17  →  11.1. Physical properties of the Group 17 elements

11. Group 17  →  11.2. The chemical properties of the halogen elements and the hydrogen halides

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15

At 550 °C nitrogen dioxide reacts with unburnt hydrocarbon fragments such as CH3• in the catalytic converter of a motor vehicle. 4CH3• + 7NO2 → 3 2 1 N2 + 4CO2 + 6H2O The following table lists types of energy change for this reaction and possible reasons for them. Which row gives the energy change for this reaction and the reason for it?

5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)

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16

Magnesium nitrate, Mg(NO3)2, will decompose when heated to give a white solid and a mixture of gases. One of the gases released is an oxide of nitrogen, X. 7.4 g of anhydrous magnesium nitrate is heated until no further reaction takes place. What mass of X is produced?

2. Atoms, molecules and stoichiometry  →  2.4. Reacting masses and volumes (of solutions and gases)

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

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17

Compound T is a white crystalline solid. When a sample of T was mixed with aqueous sodium hydroxide and heated, a pungent smelling gas was produced which turned damp red litmus paper blue. This same gas produced dense white smoke with hydrogen chloride gas. Further testing of a solution of T with barium chloride solution produced a dense white precipitate which did not dissolve when dilute hydrochloric acid was added to the mixture. What is the identity of compound T?

11. Group 17  →  11.4. The reactions of chlorine

4. States of matter  →  4.2. Bonding and structure

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

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18

Which row of the table gives correct comparisons between the solubilities of calcium and barium hydroxide and the thermal stabilities of calcium and barium carbonate?

10. Group 2  →  10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds

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19

X, Y and Z represent different halogens. The table shows the results of nine experiments in which aqueous solutions of X2, Y2 and Z2 were separately added to separate aqueous solutions containing X –, Y – and Z – ions. X –Y –Z –X2no reaction no reaction no reaction Y2X2 formed no reaction Z2 formed Z2X2 formed no reaction no reaction Which row of the following table contains the ions X –, Y – and Z – in order of their decreasing strength as reducing agents?

11. Group 17  →  11.3. Some reactions of the halide ions

15. Halogen compounds  →  15.1. Halogenoalkanes

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20

In 1865 Kekulé suggested a ring structure for benzene, C6H6, in which a hydrogen atom is attached to each carbon atom. C H H H H H H C C C C C Kekulé structure In this structure all of the bonds remain in the places shown...

13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds

13. An introduction to AS Level organic chemistry  →  13.4. Isomerism: structural isomerism and stereoisomerism

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21

The diagram shows the structure of vitamin A. OH CH3 H3C CH3 CH3 CH3 vitamin A How many chiral centres are present in one vitamin A molecule?

13. An introduction to AS Level organic chemistry  →  13.4. Isomerism: structural isomerism and stereoisomerism

20. Polymerisation  →  20.1. Addition polymerisation

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22

PVC is difficult to dispose of. Two possible methods are burying it in landfill sites and disposal by combustion. Which row of the table is correct?

20. Polymerisation  →  20.1. Addition polymerisation

2. Atoms, molecules and stoichiometry  →  2.4. Reacting masses and volumes (of solutions and gases)

14. Hydrocarbons  →  14.1. Alkanes

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23

Part of the structure of a fungicide, strobilurin, is shown...

13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

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24

Chloroethane can be used to make sodium propanoate. chloroethane → Q → sodium propanoate The intermediate, Q, is hydrolysed with boiling aqueous sodium hydroxide to give sodium propanoate. Which reagent would produce the intermediate, Q, from chloroethane?

15. Halogen compounds  →  15.1. Halogenoalkanes

14. Hydrocarbons  →  14.2. Alkenes

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25

X, Y and Z are three isomeric alcohols. X CH3CH2CH2CH2CH2OH Y CH3CH2CH(OH)CH2CH3 Z (CH3)2C(OH)CH2CH3 Two or more of these alcohols react with mild oxidising agents. One of these alcohols, when dehydrated, will give a pair of cis-trans isomers with molecular formula C5H10. Which row is correct?

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

16. Hydroxy compounds  →  16.1. Alcohols

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26

Propanone reacts with an aqueous mixture of HCN and NaCN by a nucleophilic addition mechanism. The first stage of the mechanism involves attack by cyanide ions. Which diagram correctly represents this?

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

15. Halogen compounds  →  15.1. Halogenoalkanes

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27

P, Q and R are carbonyl compounds. CH2 C P H3C H C O O CH2 C Q H H C O O CH2 C R H3C CH3 C O O Fehling’s solution can be used to help identify these compounds. Which compounds form a red-brown precipitate on warming with Fehling’s solution?

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

16. Hydroxy compounds  →  16.1. Alcohols

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28

Which reaction would not give ethanoic acid?

18. Carboxylic acids and derivatives  →  18.1. Carboxylic acids

18. Carboxylic acids and derivatives  →  18.2. Esters

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29

Which formula represents an ester that will form propanoic acid on hydrolysis with dilute sulfuric acid?

18. Carboxylic acids and derivatives  →  18.2. Esters

18. Carboxylic acids and derivatives  →  18.1. Carboxylic acids

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30

A solvent, X, used in printing inks has a molecular formula C6H10O4. It may be made by reacting ethane-1,2-diol with ethanoic acid in the presence of an acid catalyst. C HO OH H H C H ethane-1,2-diol H What is the structure of solvent X?

13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds

14. Hydrocarbons  →  14.2. Alkenes

16. Hydroxy compounds  →  16.1. Alcohols

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31

A sample of boron contains aluminium as the only impurity. A mass spectrum of the mixture shows three lines corresponding to three ions, X+, Y+ and Z+. ion X+ Y+ Z+ m / e percentage abundance 15.52 74.48 10.00 Which statements are correct?

22. Analytical techniques  →  22.2. Mass spectrometry

1. Atomic structure  →  1.1. Particles in the atom and atomic radius

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32

Which elements can form π bonds in their compounds?

13. An introduction to AS Level organic chemistry  →  13.3. Shapes of organic molecules; σ and π bonds

3. Chemical bonding  →  3.4. Covalent bonding and coordinate (dative covalent) bonding

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33

For which enthalpy changes is the value of ∆H always negative?

5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)

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34

In the manufacture of sulfuric acid, the following exothermic reaction occurs. 2SO2+ O22SO3Which changes will move the position of the equilibrium to the right?

7. Equilibria  →  7.1. Chemical equilibria: reversible reactions, dynamic equilibrium

5. Chemical energetics  →  5.1. Enthalpy change, \(\Delta H\)

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35

Water is added to anhydrous aluminium chloride to make a 0.1 mol dm–3 solution. Which observations are correct?

9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3

11. Group 17  →  11.4. The reactions of chlorine

11. Group 17  →  11.3. Some reactions of the halide ions

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36

Catalytic converters are used to modify exhaust emissions from motor vehicles. Which reactions occur in catalytic converters?

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

14. Hydrocarbons  →  14.1. Alkanes

8. Reaction kinetics  →  8.3. Homogeneous and heterogeneous catalysts

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37

Which compounds would produce a carboxylic acid and a ketone when treated with hot, concentrated, acidified KMnO4?

18. Carboxylic acids and derivatives  →  18.1. Carboxylic acids

16. Hydroxy compounds  →  16.1. Alcohols

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

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38

Bromoethane reacts with NaOH in different ways depending on the solvent used. Which statements about these reactions are correct?

15. Halogen compounds  →  15.1. Halogenoalkanes

19. Nitrogen compounds  →  19.1. Primary amines

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39

Several structural isomers of C3H6O3 are listed below. HOCH2COCH2OH HOCH2CH(OH)CHO HOCH2CH2CO2H CH3CH(OH)CO2H Which statements about these structural isomers are correct?

13. An introduction to AS Level organic chemistry  →  13.4. Isomerism: structural isomerism and stereoisomerism

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40

When onions are peeled in air, the reaction shown...

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

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