Use the following to make a set of notes on this topic

8.1 Recall that hydrocarbons are that contain and hydrogen only.

Make notes

8.2 Describe crude oil as:

a) a complex of

b) containing in which carbon atoms are in chains or rings

c) an important source of useful substances ( and feedstock for the petrochemical industry)

d) a resource. (will run out)

Make a set of notes to explain how fractional distillation is used the separate the fractions in crude oil

• Heating: Crude oil is heated to a high temperature (around 350°C) in a furnace, causing it to .

• Fractionating Column: The hot vaporized crude oil enters the of a fractionating column.

• Temperature Gradient: There is a temperature gradient within the column, with the hottest temperature at the bottom and the coolest at the .

• Condensation: As the vaporized crude oil rises through the column, it cools. Hydrocarbons with higher boiling points condense back into liquids at levels in the column, where the temperature is higher. Hydrocarbons with lower boiling points continue to rise until they reach a cooler level where they .

• Collection: The condensed liquid fractions are on the trays and drawn off through pipes.

Fractional distillation and hydrocarbon properties

1 =

2 =

3 =

4 =

This is a typical structure and bonding 6 mark question and is worth having as a model answer in your notes.

Describe the relationship shown by the graph and use ideas about forces between molecules to explain this relationship.

The more carbons the higher the point

The carbons the larger the molecules.

larger molecules have boiling points

Larger molecules have larger forces them

The larger the forces between the molecules the more is required for them to break out of a liquid and become a

the more energy needed to the molecules, the higher the boiling point of the hydrocarbon

the larger / more the forces between the the higher the boiling point

(The key idea is that we are overcoming the intermolecular forces not breaking the strong covalent bonds so the values are low and the first 3 are gasses at room temperature).

Complete and copy into your notes

8.6 Explain an homologous series as a series of which:

a) have the same general (e.g. C_nH_2n+2 for alkanes and C_nH_2n for alkenes)

b) differ by in molecular formulae from neighbouring compounds. (The alkanes methane, ethane, propane and butane have the formulae CH₄, C₂H₆, C₃H₈ and C₄H₁₀)

Complete and copy into your notes

c) show a gradual variation in physical properties, as exemplified by their points which increases as the chain length

d) have similar chemical properties for example alkanes can undergo