What level will you reach?...To get a grade D: you will explain how we obtain and separate crude oilTo get a grade C: you should give examples of alkanes obtained from crude oil and be able to draw structural and molecular formulae for themTo get a grade B: you should evaluate crude oil as a resource To get a grade A/A*: you should suggest alternatives to crude oil, based on environmental, economic and social factors

What can you remember about…

• how to obtain crude oil?

• how to separate crude oil?

• how alkanes are named?

• how good crude oil is as a fuel?

• any alternative fuels?

You have5 minutes!

Crude Oil

• Microscopic plants and animals die and fall to the sea bed• Layers of sand and mud form on top• Pressure and high temperature cause oil to form

How crude oil was formed

• Oil obtained by drilling

Heated Crude Oil

350oC

40oC

Liquid petroleum gas

Naphtha

Petrol (gasoline)

Paraffin

Diesel

Fuel oil

Lubricating oil

Bitumen

Fraction Boiling pt.

< 25oC

25 – 60oC

60 – 180oC

180 – 220oC

220 – 250oC

250 – 300oC

300 – 350oC

> 350oC

Average number of C atoms in chain

3

8

10

12

20

40

80

120

The Fractional Distillation of Crude Oil

Properties of the fractions

The compounds produced by the distillation of crude oil are all hydrocarbons.

Hydrocarbons are compounds which contain the elements hydrogen and carbon.

Naming hydrocarbons

Alkanes

Methane

Ethane Propane

These hydrocarbons are said to be saturated. (They have single bonds between carbon atoms).

C2H6 C3H8CH4

Fuels

Most alkanes are used as fuels to produce useful forms of energy.

When completely burned alkanes form carbon dioxide and water.

Equations for combustion

CH4

methane

+ O2

oxygen

CO2

carbon dioxide

+ H2O

water

2 2

C3H8 + O2 CO2 + H2O

C2H4 + O2 CO2 + H2O2 2

5 3 4

3

Combustion of hydrocarbonsWhen burned with sufficient oxygen, hydrocarbons form

carbon dioxide and water

Global dimming

Particulates in soot come from the incomplete combustion of fuel leaving carbon particles. These particles cause Global Dimming by reflecting sunlight away from the Earth.

Global Warming

• main cause: carbon dioxide from burning fossil fuels causing a “greenhouse” effect (also methane).

• Effect on the environment?

• Reducing the Problem?

Acid rain

• Main cause: sulfur compounds in fuels burning to form sulphur dioxide which dissolves in rainwater to produce an acidic solution ( also causes nitrogen oxides from car exhausts.

• Effect on the environment?

• Reducing the problem?

Hydrogen: produced by passing an electric current through water and the process therefore requires lots of energy. Hydrogen is highly flammable and would have to be stored under special conditions.

Only product is water, therefore no pollution.

Hydrogen + Oxygen Water + Energy

Ethanol is made by fermentation of sugar (this process is used to make alcoholic drinks).

It is made from sugar cane which comes from countries such as Brazil. Ethanol burns more cleanly than petrol but produces less energy. It also form carbon dioxide (but it is carbon neutral since the plants absorbed it in the first place.

What level did you reach?...To get a grade D: you will explain how we obtain and separate crude oilTo get a grade C: you should give examples of alkanes obtained from crude oil and be able to draw structural and molecular formulae for themTo get a grade B: you should evaluate crude oil as a resource To get a grade A/A*: you should suggest alternatives to crude oil, based on environmental, economic and social factors