C7- Organic Chemistry

Question 1

Hydrocarbon

Answer 1

A compound that is formed from carbon and hydrogen atoms

Question 2

Alkanes

Answer 2

Simplest type of hydrocarbom general formula CnH2n+2

Question 3

First four alkanes

Answer 3

Methane, ethane, propane, butane

Question 4

Methane

Answer 4

CH4

Question 5

Ethane

Answer 5

C2H6

Question 6

Propane

Answer 6

C3H8

Question 7

Butane

Answer 7

C4H10

Question 8

Hydrocarbon property

Answer 8

The shorter the carbon chain, the less viscous it is, more volatile, more flammable

Question 9

Complete combustion

Answer 9

Hydrocarbon + oxygen -> carbon dioxide + water + energy

Question 10

Crude oil

Answer 10

Mixture of lots of different hydrocarbons

Question 11

How crude oil seperated by fractional distillation

Answer 11

1. Heated until most of it turned into gas. The gases eneter a fractionating column
2. In column temperature gradient (hot at bottoms and colder as you go up)
3. Longer hydrocarbons have higher boiling points they condense back into liquids and drain out the shorter hydrocarbons condense and drain out much later on, near to the top of the column where it’s cooler

Question 12

Crude oil uses

Answer 12

Provides for most modern transport, petrochemical uses hydrocarbons from crude oil as a feedstock to make new compounds,

Question 13

Cracking

Answer 13

Splitting up long-chain hydrocarbons

Question 14

Test for alkenes

Answer 14

1.Bromine water added to alkene birght orange
2. If it’s added to an alkene the bromine reacts with the alkene to mske a colourless compound

Question 15

Steps of catalystic cracking

Answer 15

Thermal decomposition reaction- breaking molecules down by heating them
1. Heat long chain hydrocarbons to vaporise them
2. Vapour passed over a hit powdered alumninium oxide catalyst
3. Long-chain molecules split apart on the surface of the specks of catalyst- catalystic cracking