Crude Oil

Question 1

Crude oil is derived from what?

Answer 1

Ancient biomass found in rocks.

Question 2

True or false…crude oil is a mixture of a small number of compounds.

Answer 2

False. Crude oil is a mixture of a very large number of compounds.

Question 3

A mixture consists of…

Answer 3

…two or more compounds not chemically bonded together.

Question 4

It is possible to separate a mixture such as crude oil by what method?

Answer 4

Fractional distillation.

Question 5

Most of the compounds found in crude oil are what?

Answer 5

Hydrocarbons.

Question 6

What is a hydrocarbon?

Answer 6

A compound made only of hydrogen and carbon atoms.

Question 7

Most hydrocarbons in crude oil are saturated…

Answer 7

…alkanes, which have the general formula CnH2n+2.

Question 8

Fractional distillation is the process of…

Answer 8

…evaporating crude oil into fractions of similarly lengthen molecules in a column. At different temperatures the crude oil condenses at different lengths up the column where it is collected.

Question 9

Properties of hydrocarbons may depend upon their…

Answer 9

…length (number of carbon atoms).

Question 10

Fractions are…

Answer 10

…mixtures of hydrocarbons with a similar number of carbon atoms. This is because they have similar boiling/melting points.

Question 11

A larger hydrocarbon has what properties?

Answer 11

Higher boiling points.
More viscous.
Less volatile.
Less flammable.

Question 12

During combustion of a hydrocarbon, energy is released. Hydrogen and carbon become…

Answer 12

…oxidised.

Question 13

Environmental problems with hydrocarbons combusting.

Answer 13

Sulphur dioxide and oxides of nitrogen cause acid rain, carbon dioxide is a greenhouse gas and causes global warming, whilst solid particles cause global dimming.

Question 14

How can acid rain be prevented during the combustion of hydrocarbons?

Answer 14

Sulphur can be removed before the fuels are burnt and sulphur dioxide can be removed from waste gases after combustion (eg: in power stations).

Question 15

An alternative fuel to hydrocarbons?

Answer 15

Biofuels (eg: biodiesel and ethanol).

Question 16

Hydrocarbons can be made smaller by what method?

Answer 16

Cracking.

Question 17

How does cracking work?

Answer 17

Hydrocarbons are vaporised and passed over a catalyst where thermal decomposition takes place.

Question 18

What are the products of cracking?

Answer 18

Alkanes and smaller unsaturated hydrocarbons called alkenes.

Question 19

What is the general formula for alkenes?

Answer 19

CnH2n

Question 20

What test can be done to see if an unsaturated alkene is present?

Answer 20

Mix with bromine water. If alkenes are present it will turn form orange to colourless.

Question 21

Alkenes can be joined to make what type of materials?

Answer 21

Polymers.

Question 22

What is a polymer?

Answer 22

A chain of monomers (single molecules). Eg: Ethene can be used to make polyethene.

Question 23

Uses of polymers.

Answer 23

Food packaging, waterproofs, wound dressings, dental polymers, smart materials (including shape memory foams).

Question 24

How are plastic bags being made biodegradable?

Answer 24

They are being made of polymers and cornstarch so that the break down more easily.

Question 25

How can ethanol be made?

Answer 25

1)Hydration of ethene with steam over a catalyst.
or
2)Fermentation with yeast:

Sugar = carbon dioxide + ethanol