| State the main components in the air and the percentage they are found in the atmosphere | Nitrogen- 78%
Oxygen-21%
The rest 1%
Mainly argon
some carbon dioxide
other noble gases |
| Describe the steps in fractional distillation of air which is used to separate oxygen, nitrogen, noble gases | 1) Air is pumped in and filtered to remove the dust
2)Water vapour, carbon dioxide and pollutants are removed
3)The air is compressed which makes it hot, it is cooled down again by recycling cold air
4)The cold compressed air is passed into a larger space where it expands rapidly making it very cold .
5) The mixture is slowly warmed up where each liquid boils one by one |
| Give three uses of oxygen. | People who have breathing difficulties are given oxygen through an oxygen mask
Oxygen is used in converting the impure iron from the blast furnace into steel
Oxygen is required in welding torches |
| For each gas state how it is formed and what harm it does
Carbon Dioxide
Sulfur Dioxide
Nitrogen oxides | Carbon Dioxide
-Formed when carbon compounds in fossil fuels burn in a limited supply of air
-Reacts with haemoglobin in blood, preventing it from carrying oxygen around the body, you could die from oxygen starvation
Sulfur dioxide
-Formed when sulfur compounds in fossil fuels are burnt and from volcanoes
-Dissolves in rain water to form sulfuric acid which result in acid rain
Nitrogen oxides
-Forms when nitrogen and oxygen in air react together inside hot car engines and hot furnaces
-Dissolves in rain to form nitric acid which results in acid rain |
| What is flue gas desulfurisation? | Calcium hydroxide(slaked lime) is added to waste gas, so sulfur dioxide to be removed by reacting with calcium hydroxide to give calcium sulfate. |
| What do catalytic converters in the exhausts do? | It speed up the reaction of...
Reduction of nitrogen oxide to give nitrogen and oxygen
the oxygen made here is used to...
Oxidise carbon monoxide to form carbon dioxide |
| What two components are required by iron in order to rust? | Oxygen and water |
| Why is charcoal(carbon) used in water purification? | When water passes through charcoal bad tastes and smells are removed from the water. |
| Why is water passed through a bed of sand ? | Water is passed through a bed of sand to remove solids |
| Why is chlorine added to water? | Chlorine is added to kill bacteria and other microbes |
