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1

In which reaction does an element undergo the largest change in oxidation state?

6. Electrochemistry  →  6.1. Redox processes: electron transfer and changes in oxidation number (oxidation state)

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2

Use of the Data Booklet is relevant to this question. The 68Ge isotope is medically useful because it undergoes a natural radioactive process to give a gallium isotope, 68Ga, which can be used to detect tumours. This transformation of 68Ge occurs when an electron enters the nucleus, changing a proton into a neutron. Which statement about the composition of an atom of the 68Ga isotope is correct?

1. Atomic structure  →  1.2. Isotopes

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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3

Sodium borohydride, NaBH4, and boron trifluoride, BF3, are compounds of boron. What are the shapes around boron in the borohydride ion and in boron trifluoride?

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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4

Use of the Data Booklet is relevant to this question. A reaction which causes the presence of oxides of nitrogen in car exhausts is the formation of NO. N2 + O2 → 2NO ∆H = +180 kJ mol–1 What is the bond energy in kJ mol–1 of the bond between the atoms in NO?

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

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

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5

In the table below, • ‘+’ means that this type of standard enthalpy change can only have positive values, • ‘–’ means that this type of standard enthalpy change can only have negative values, • ‘+ / –’ means that either positive or negative values are possible. Which row is correct?

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

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6

Use of the Data Booklet is relevant to this question. The volume of a sample of ammonia is measured at a temperature of 60 °C and a pressure of 103 kPa. The volume measured is 5.37 × 10–3 m3. What is the mass of the sample of ammonia, given to two significant figures?

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

22. Analytical techniques  →  22.2. Mass spectrometry

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7

Aluminium is extracted by the electrolysis of a molten mixture containing aluminium oxide. By a similar method, magnesium is extracted by the electrolysis of a molten mixture containing magnesium chloride. Which statement about the extraction of magnesium is correct?

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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8

Some car paints contain small flakes of silica, SiO2. In the structure of solid SiO2 ● each silicon atom is bonded to x oxygen atoms, ● each oxygen atom is bonded to y silicon atoms, ● each bond is a z type bond. What is the correct combination of x, y and z in this statement?

4. States of matter  →  4.2. Bonding and structure

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

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9

John Dalton’s atomic theory, published in 1808, contained four predictions about atoms. Which of his predictions is still considered to be correct?

2. Atoms, molecules and stoichiometry  →  2.1. Relative masses of atoms and molecules

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

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10

A student calculated the standard enthalpy change of formation of ethane, C2H6, using a method based on standard enthalpy changes of combustion. He used correct values for the standard enthalpy change of combustion of ethane (–1560 kJ mol–1) and hydrogen (–286 kJ mol–1) but he used an incorrect value for the standard enthalpy change of combustion of carbon. He then performed his calculation correctly. His final answer was –158 kJ mol–1. What did he use for the standard enthalpy change of combustion of carbon?

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

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11

Which process could be used to calculate the bond energy for the covalent bond X-Y by dividing its ∆H by n?

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

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

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12

In which pair do the molecules have the same shape as each other?

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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13

Why is the ionic radius of a chloride ion larger than the ionic radius of a sodium ion?

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

3. Chemical bonding  →  3.2. Ionic bonding

1. Atomic structure  →  1.4. Ionisation energy

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14

What are the trends in the stated properties as Group II is descended from magnesium to barium?

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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15

Use of the Data Booklet is relevant to this question. The nitrates of beryllium, calcium, magnesium, and strontium all decompose in the same way when heated. When 2.00 g of one of these anhydrous nitrates is decomposed, 1.32 g of gas is produced. What is the nitrate?

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

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

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16

In a car engine, non-metallic element X forms a pollutant oxide Y. Y can be further oxidised to Z. Two students made the following statements. Student P The molecule of Y contains lone pairs of electrons. Student Q The oxidation number of X increases by 1 from Y to Z. X could be carbon or nitrogen or sulfur. Which student could be correct if X were any of these elements?

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

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

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17

Use of the Data Booklet is relevant to this question. 1.15 g of a metallic element reacts with 300 cm3 of oxygen at 298 K and 1 atm pressure, to form an oxide which contains O2– ions. What could be the identity of the metal?

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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18

Elements X and Y are both in period three. When the chloride of X is added to water, it reacts and a solution of pH 2 is produced. When the chloride of Y is added to water, it dissolves and a solution of pH 7 is produced. Which statement explains these observations?

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

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19

Which diagram shows the variation of the metallic radius r of the Group I elements, Li, Na, K and Rb, with increasing proton number?

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

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

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20

Carvone is found in spearmint. C C C C CH2 H3C H2C CH2 CH3 C H H O carvone How many σ and π bonds are present in this molecule?

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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21

An alkene has the formula CH3CH=CR CH2CH3 and does not possess cis-trans isomers. What is R ?

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

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22

Menthol is an important compound extracted from the peppermint plant. OH CH3 CH3 H3C menthol How many chiral centres are there in one molecule of menthol?

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

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

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23

The cracking of a single hydrocarbon molecule, CnH2n+2, produces two hydrocarbon molecules only. Each hydrocarbon product contains the same number of carbon atoms in one molecule. Each hydrocarbon product has non-cyclic structural isomers. What is the value of n?

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

14. Hydrocarbons  →  14.1. Alkanes

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24

But-2-ene-1,4-diol is converted in two steps through an intermediate X into ketobutanedioic acid. HOCH2CH=CHCH2OH X HO2CCOCH2CO2H but-2-ene-1,4-diol ketobutanedioic acid hot acidified KMnO4 step 1 step 2 What could be the reagent for step 1 and the intermediate X?

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

18. Carboxylic acids and derivatives  →  18.1. Carboxylic acids

14. Hydrocarbons  →  14.2. Alkenes

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25

One of the reactions taking place in a catalytic converter in a car exhaust system is between nitrogen oxide and octane (unburned petrol). The products of this reaction are non-toxic. Which is the correct equation for the reaction?

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

14. Hydrocarbons  →  14.1. Alkanes

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26

High-energy radiation in the stratosphere produces free-radicals from chlorofluoroalkanes, commonly known as CFCs. Which free-radical is most likely to result from the irradiation of CHFCl CF2Cl ?

14. Hydrocarbons  →  14.1. Alkanes

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

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27

Which reagent reacts with ethanol and also reacts with ethanoic acid?

16. Hydroxy compounds  →  16.1. Alcohols

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

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28

In 1903 Arthur Lapworth became the first chemist to investigate a reaction mechanism. The reaction he investigated was that of hydrogen cyanide with propanone. What do we now call the mechanism of this reaction?

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

13. An introduction to AS Level organic chemistry  →  13.2. Characteristic organic reactions

14. Hydrocarbons  →  14.2. Alkenes

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29

Many, but not all, organic reactions need to be heated before reaction occurs. Which reaction occurs at a good rate at room temperature (20 °C)?

13. An introduction to AS Level organic chemistry  →  13.2. Characteristic organic reactions

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

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30

Compound X, C6H12O, is oxidised by acidified sodium dichromate(to compound Y. Compound Y reacts with ethanol in the presence of a little concentrated sulfuric acid to give liquid Z. What is the formula of Z?

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

18. Carboxylic acids and derivatives  →  18.1. Carboxylic acids

16. Hydroxy compounds  →  16.1. Alcohols

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31

How may nitrogen exist in compounds?

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

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

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32

Use of the Data Booklet is relevant to this question. The isotope 99Tc is radioactive and has been found in lobsters and seaweed adjacent to nuclear fuel reprocessing plants. Which statements are correct about an atom of 99Tc?

1. Atomic structure  →  1.2. Isotopes

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

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33

Which of these substances have a giant structure?

4. States of matter  →  4.2. Bonding and structure

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

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34

The element astatine, At, is below iodine in Group VII of the Periodic Table. Which statements concerning At will be correct?

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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35

Which equations represent stages in the Contact process for manufacturing sulfuric acid?

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

12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur

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

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36

When added to water, which oxides will not cause a change in pH?

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

7. Equilibria  →  7.2. Brønsted–Lowry theory of acids and bases

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37

Which reagents and conditions will convert propane into 1-chloropropane?

14. Hydrocarbons  →  14.1. Alkanes

14. Hydrocarbons  →  14.2. Alkenes

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38

Chloroethane can be formed from bromoethane in two steps. C2H5Br C2H5OH step X C2H5Cl step Y Which statements about these steps are correct?

15. Halogen compounds  →  15.1. Halogenoalkanes

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39

Which reagents react with butanone, C2H5COCH3?

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

15. Halogen compounds  →  15.1. Halogenoalkanes

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40

Oleic acid is found in olive oil. It has the following formula. C C C H H O OH CH3(CH2)7 (CH2)7 Which reagents will give a positive result with oleic acid?

18. Carboxylic acids and derivatives  →  18.1. Carboxylic acids

17. Carbonyl compounds  →  17.1. Aldehydes and ketones

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