1. UNIT 3
CHEMISTRY
IN SOCIETY
(From August 2017)

4. The manufacture of potassium nitrate, for use in fertilisers, can be split into three stages.
(a) In stage 1, ammonia is produced.
Name the industrial process used to
manufacture ammonia.
(b) Name the catalyst used in the
manufacture of ammonia.
HABER
IRON

5. AS TEMP GOES UP SOLUBILITY GOES DOWN

6. PERCENTAGE YIELD GOES UP
AS PRESSURE GOES UP
PERCENTAGE YIELD GOES UP
Describe the relationship between the yield of
ammonia and pressure.

8. Calculate the percentage mass of nitrogen in (NH4)2SO4
N x x 2 = Formula mass =
H x x 8 = = 132g
S x x 1 = 32
O x x 4 = 64
Mass of nitrogen = 28g
Percentage of nitrogen 28/132 x 100 = 21∙2%.
Also accepted 21%

9. Which diagram represents a metal?

10. Metallic bonding is a force of attraction
between
A positive ions and delocalised
electrons
B negative ions and delocalised
C negative ions and positive ions
D a shared pair of electrons and two
nuclei.

11. Which of the following metals will not react with a dilute solution of hydrochloric acid?
A Copper
B Iron
C Magnesium
D Zinc

13. What is the name given to naturally occurring compounds of metals such as bauxite?
ORE
Name the type of chemical reaction taking place when metal ions are changed to metal atoms during the extraction of a metal from its ore.
REDUCTION

14. Aluminium can be extracted from aluminium oxide by
A heating alone
B heating with carbon
C heating with carbon monoxide
D electrolysis.

15. Some metals can be obtained from their metal oxides by heat alone.
Which of the following oxides would produce a metal when heated?
A Calcium oxide
B Copper oxide
C Zinc oxide
D Silver oxide

16. Which pair of metals, when connected in a cell, would give the highest voltage and a flow of electrons from X to Y?

17. In the cell shown electrons flow through
A the solution from copper to tin
B the solution from tin to copper
C the wires from copper to tin
D the wires from tin to copper.

19. In some fuel cells hydrogen gas is used as the fuel.
a. State an advantage of using a fuel cell.
b. Write an ion-electron equation for the
formation of hydrogen

21. The ion-electron equations taking place at the electrodes are:
Na+ + e– → Na
2H– → H e–
Write the overall redox equation for the reaction.
2Na+ + 2H– → 2Na + H2

22. The ion-electron equations taking place at the electrodes are:
Al e– → Al
2H– → H e–
Write the overall redox equation for the reaction.
2Al H– → 2Al + 3H2

23. The ion-electron equations taking place at the electrodes are:
Al e– → Al
2O2– → O e–
Write the overall redox equation for the reaction.
4Al O2– → 4Al + 3O2

24. 2K+(aq) + 2I–(aq) + Pb2+(aq) + 2NO3–(aq)↓
Pb2+(I–)2(s) K+(aq) NO3–(aq)
The type of reaction represented by the
equation above is
A addition
B neutralisation
C precipitation
D redox.

27. H+(aq) + NO3–(aq) + K+(aq) + OH–(aq)
K+(aq) NO3–(aq) H2O
The spectator ions in the reaction are
A H+(aq) and K+(aq)
B NO3–(aq) and OH–(aq)
C H+(aq) and OH–(aq)
D K+(aq) and NO3–(aq).

28. Some smoke detectors make use of radiation
which is very easily stopped by tiny smoke
particles moving between the radioactive
source and the detector.
The most suitable type of radioisotope for a
smoke detector would be
A an alpha-emitter with a long half-life
B a gamma-emitter with a short half-life
C an alpha-emitter with a short half-life
D a gamma-emitter with a long half-life.

29. 11 ALPHA SODIUM The half-life of a radioisotope is 8 days.
Calculate the mass of a 16g sample that would remain after 24 days.
The nuclear equation shows how a radioisotope of element X can be made from aluminium.
Name the type of radiation emitted.
Name element X. 11
ALPHA
SODIUM

30. Name the type of radiation emitted.84
Name the type of radiation emitted.
Name element X
ALPHA
POLONIUM

31. A radioisotope of thorium forms
protactinium-231 by beta-emission.
What is the mass number of the radioisotope of thorium?
A 230
B 231
C 232
D 235

32. ½ 0·5 remains after 21 years
¼ 0·25 remains after 2 x 21 years
= 42 years
⅛ 0·125 remains after 3 x 21 years
= 63 years

33. How many years have passed since the wood for the fire was cut?
14C has a half life of 5600 years. An analysis of charcoal from a wood fire shows that its I4C content is 25% that of living wood.
How many years have passed since the wood for the fire was cut?
A 1400
B 4200 C D
½ 0·5 remains after 5600 years
¼ 0·25 remains after 2 x 5600 years
= years
2 half lives 2 x 5600 =

34. 1g remains after 2 x 6 hours = 12 hours
Technetium-99m is used in medicine to detect damage to heart tissue.
(a) The half-life of technetium-99m is 6 hours.
How much of a 4g sample of technetium-99m
would be left after 18 hours?
2g remains after 6 hours
1g remains after 2 x 6 hours = 12 hours
0·5g remains after 3 x 6 hours = 18 hours

35. Technetium-99m is used in medicine to detect damage to heart tissue.
(b) Suggest one reason why technetium-99m can be
used safely in this way.
Short half life

36. State the colour of flame for
potassium
sodium
lithium
copper
lilac
yellow
red
blue-green

38. What is the average volume of hydrochloric acid
that should be used.
15∙ ∙7 = 31∙2
31∙2 /2 = 15∙6 cm3

39. 16·1 + 15·9 / 2 = 16 Calculate the average volume used.
Using bromine solution, a student carried out titrations to determine the concentration of limonene in a household cleaner.
16·1 + 15·9 / 2 = 16
Calculate the average volume used.

40. 0·50 x 16 = C x 20
= C x 20
C = 4/20 = 0·2
The equation for the reaction between limonene and bromine solution is shown.
C10H16(aq) Br2(aq) C10H16Br4(aq)
Calculate the concentration of limonene in the household cleaner.

41. 0·10 x 24·6 = C x 20
2· = C x 20
C = 2·46/20
= 0·123

42. 0·5 x 33·4 = C x 20
16· = C x 20
C = 16·7/20
= 0·835

43. 0·1 x 22·4 = C x 25
1· = C x 25
C = 1·12/25
= 0·0448