5.7.1 Carbon compounds as fuels and feedstock

Hydrocarbons

Compounds composed of only carbon and hydrogen

Alkanes

a hydrocarbon containing only single bonds

Genral formula for Alkanes

CnH2n+2

What are the first 4 alkanes

methane, ethane, propane, butane

crude oil

finite resource found in rocks

What is crude oil mainly made from?

(remains of plants and animals) mainly Plankton

Alkanes are part of which series?

homologous series

Viscosity

A liquid's resistance to flowing (how runny) - viscous \= gloopy

What does a shorter chain hydrocarbon do to the substances viscosity?

Makes it more runny (less viscous)

What does a shorter chain hydrocarbon do to the substances Boiling point?

Lowers boiling point (more volatile)

What does a shorter chain hydrocarbon do to the substances flammability?

Makes it more flammable

What is released during combustion of hydrocarbons?

Energy

Word equation for hydrocarbon combustion?

hydrocarbon + oxygen --\> carbon dioxide + water (+energy)

What happens to the hydrogen and carbon during the reaction?

they are oxidised

What does the complete combustion of a hydrocarbon produce?

carbon dioxide and water.

What are hydrocarbons used as?

fuels

What is crude oil a mix of?

A mixture of hydrocarbons

What are the uses of hydrocarbons?

- fuels (cars, trains planes...)
- feedstocks (petrochemical industry uses them to make new compounds) Eg:
- polymers
- solvents
- lubricants

What are all the compounds in crude oil examples of? Why?

organic compounds because they all contain carbon atoms

What is fractional distillation?

It is the separation of hydrocarbons into crude oil into fractions according to their chain length.

How does fractional distillation work?

Hot crude oil enters near the bottom of a fractioning column.
Temperature decreases up the column.
By evaporation and condensation up the column, the oil is separated into 'fractions' with different boiling ranges, which are tapped off at different heights.

What is cracking?

Long chain hydrocarbons being split into shorter chain hydrocarbons

What are some methods of cracking?

catalyticcracking and steam cracking.

Products of cracking

Alkanes and alkenes

Which are more reactive alkanes or alkenes?

alkenes

What are alkanes and alkenes used for?

As starting materials when making lots of other compounds

What can be used to test for alkenes?

Bromine water

What colour is bromine water when added to an alkene?

colourless