UNIT 3 CHEMISTRY IN SOCIETY (From August 2017)

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

AS TEMP GOES UP SOLUBILITY GOES DOWN

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

Calculate the percentage mass of nitrogen in (NH4)2SO4 N x 2 14 x 2 = 28 Formula mass = H x 8 1 x 8 = 8 28 + 8 + 32 + 64 = 132g S x 1 32 x 1 = 32 O x 4 16 x 4 = 64   Mass of nitrogen = 28g Percentage of nitrogen 28/132 x 100 = 21∙2%. Also accepted 21%

Which diagram represents a metal?

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.

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

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

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

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

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

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.

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

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

The ion-electron equations taking place at the electrodes are: Al3+ + 3e– → Al 2H– → H2 + 2e– Write the overall redox equation for the reaction. 2Al3+ + 6H– → 2Al + 3H2

The ion-electron equations taking place at the electrodes are: Al3+ + 3e– → Al 2O2– → O2 + 4e– Write the overall redox equation for the reaction. 4Al3+ + 6O2– → 4Al + 3O2

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

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).

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.

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

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

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

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

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 11 200 D 16 800 ½ 0·5 remains after 5600 years ¼ 0·25 remains after 2 x 5600 years = 11 200 years 2 half lives 2 x 5600 = 11 200

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

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

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

What is the average volume of hydrochloric acid that should be used. 15∙5 + 15∙7 = 31∙2 31∙2 /2 = 15∙6 cm3

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.

0·50 x 16 = C x 20 2 1 4 = C x 20 C = 4/20 = 0·2 The equation for the reaction between limonene and bromine solution is shown. C10H16(aq) + 2Br2(aq) C10H16Br4(aq) Calculate the concentration of limonene in the household cleaner.

0·10 x 24·6 = C x 20 1 1 2·4 6 = C x 20 C = 2·46/20 = 0·123

0·5 x 33·4 = C x 20 1 1 16·7 = C x 20 C = 16·7/20 = 0·835

0·1 x 22·4 = C x 25 2 1 1·12 = C x 25 C = 1·12/25 = 0·0448