Define isomer
Molecules with the same molecular formula but different structures
Define hydrocarbons
Molecules that contain only hydrogen and carbon, and have all single bonds
Why are alkanes classified as hydrocarbons
They are chains of carbon atoms surrounded by hydrogen atoms. They contain only hydrogen and carbon
What is the general formula for alkanes
CnHn+1
Name the first 6 alkanes
Methane, ethane, propane, butane, pentane, hexane
Describe the process of fractional distillation of crude oil
The oil is heated until most of turns into gas. The gas then enters a fractionating column
In the column there is a temperature gradient (hot at the bottom, cool at the top)
When the substances reach a part of the column where the temperature is lower than their boiling point they condense.
The longer hydrocarbons have high boiling point, and condense at the bottom
The shorter hydrocarbons have lower boiling points, so they condense at the top
The crude oil has now been split into its fractions
What is the order of fractions from top to bottom
Refinery gases, gasoline, kerosene, diesel, fuel oil, bitumen
What properties do hydrocarbons have as you go down the fractionating column
their boiling points get higher
Their length gets longer
They get more viscous
They get darker
Uses of refinery gases
Domestic heating and cooking
Uses of gasoline
Fuel in cars
Uses of kerosene
Fuel for planes
Uses of diesel
Fuel for trains and lorries
Uses of fuel oil
Fuel for large ships and power stations
Uses of bitumen
Surface roads and roofs
How is acid rain caused by burning hydrocarbons
the fuels obtained from the hydrocarbons are burnt
There are some sulfur impurities present in the hydrocarbon fuels
When these impurities are burnt, sulfur dioxide is produced
When sulfur dioxide mixes with water vapour, it produces dilute sulfuric cid
This could lead to acid rain when these clouds fall
The acid rain causes lakes to become acidic and kills plants/animals.