5.11 understand that, in car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming nitrogen oxides

The temperature in a car engine is high enough for nitrogen and oxygen from the air to react to form oxides of nitrogen. These oxides are also passed out through the exhaust of the car and when they get into the atmosphere, they can dissolve in the water in the air to form acid rain.

5.10 understand that incomplete combustion of fuels may produce carbon monoxide and explain that carbon monoxide is poisonous because it reduces the capacity of the blood to carry oxygen

Incomplete combustion of an alkane produces carbon monoxide. The same is true when petrol or diesel is burnt in cars, some of the fuel is not completely burnt because of the lack of oxygen.

The carbon monoxide produced passes out through the exhaust pipe of the car and gets into the atmosphere. This is potentially dangerous, since carbon monoxide is poisonous to humans as it reduces the capacity of the blood to carry oxygen.

5.9 describe the trend in boiling point and viscosity of the main fractions

The lower down the fraction, the higher the boiling point.

The higher the boiling point, the lower the viscosity, the lower the boiling point the higher the viscosity.

5.8 recall the names and uses of the main fractions obtained from crude oil: refinery gases, gasoline, kerosene, diesel, fuel oil and bitumen

Uses of the products of the main fractions

Refinery gases: bottles gas for camping etc.

Gasoline: petrol for cars

Kerosene: fuel for aeroplanes

Diesel oil: fuel for buses, lorries, trains and cars

Fuel oil: fuel for ships and industrial heating

Bitumen: road surfaces and covering flat roofs for buildings.

5.7 describe and explain how the industrial process of fractional distillation separates crude oil into fractions

Fractional distillation

Crude oil, as such, has no direct use. It has to be refined before it is any use. The first step in the refining of crude oil is fractional distillation.

Fractional distillation is carried out in a fractionating column. The column is hot at the bottom and gradually becomes cooler at the top. 

The crude oil is split into various fractions as described below. A fraction is a mixture of hydrocarbons with very similar boiling points. 

Crude oil is heated to convert it into a vapour. The vapour is then fed into the bottom of the fractionating column.

The hydrocarbons with very high boiling points (fuel, oil and bitumen) immediately turn into liquids and are tapped off at the bottom of the column.

5.6 understand that crude oil is a mixture of hydrocarbons

Crude oil is a thick, sticky, black liquid that is found under the ground and under the sea in certain parts of the world such as he Middle East and Texas, USA.

It is a mixture of hydrocarbons, mostly alkanes.

5.5 explain the uses of aluminium and iron, in terms of their properties.

Uses of aluminium and iron

Aluminium :

• aeroplane bodies: high strength-to-weight ratio
• overhead power cables: good conductor of electricity
• saucepans: good conductor of heat
• food cans: non-toxic
• window frames: resists corrosion

Iron

• car bodies: strong
• iron nails: strong
• ships, girders and bridges: strong