Organic Chemistry 2

Question 1

What is a hydrocarbon

Answer 1

Compound containing only hydrogen and carbon

Question 2

What bonds do alkanes have?

Answer 2

Single c-c bonds

Question 3

Name 4 alkanes

Answer 3

Methane
Propane
Ethane
Butane

Question 4

Symbol for methane

Answer 4

Ch4

Question 5

Symbol for ethane

Answer 5

C2h6

Question 6

Symbol for propane

Answer 6

C3h6

Question 7

Symbol for butane

Answer 7

C4h10

Question 8

Long hydrocarbons have a higher …..

Answer 8

Boiling point

Question 9

Long hydrocarbons have a lower v…… And f……..

Answer 9

Volatility

Flammability

Question 10

When does complete combustion occur

Answer 10

When there is plenty of oxygen

Question 11

What is the complete combustion of any hydrocarbon in o….. Releases lots of e…..

Answer 11

Oxygen

Energy

Question 12

Name the 2 waste products in complete combustion and what is the word equation

Answer 12

Carbon dioxide and water

Hydrocarbon + oxygen -> carbon dioxide + water

Question 13

During combustion what happens to carbon and hydrogen from the hydrocarbon?

Answer 13

They are oxidised

Question 14

What are hydrocarbons used for and why?

Answer 14

Fuels

Due to the amount of energy they release when they combust completely

Question 15

Crude oil is a fossil fuel. What is it made from?

Answer 15

Remains of plants, animals, plankton that has died millions of years ago and were buried in mud.

Question 16

What can be used to separate hydrocarbon fractions

Answer 16

Fractional distillation

Question 17

Explain the 4 steps of how fractional distillation works

Answer 17

1- oil heated till most is gas. Gas enters FRACTIONATING COLUMN.
2- in there is temperature gradient (hot bottom cool top)
3- longer hydrocarbons high boiling points- condense back to liquids drain out early column bottom. Shorter lower boiling points drain out much later on near top
4- end up with crude oil mixtures separated out into fractions.

Question 18

3 uses crude oil has

Answer 18

1- oil,provides fuel for most transport
2- petrochemical industry uses some hydrocarbons as feedstock to make new compounds for things like polymers, solvents, lubricants
3- egs of organic compounds. Can bond to form homologous series. Alkenes and alkanes.

Question 19

What does cracking mean

Answer 19

Splitting up long hydrocarbon chains

Question 20

Why do we split long chain hydrocarbons

Answer 20

Because they form thick gloopy liquids like tar which isn’t very useful so they are turned into smaller more useful product with cracking

Question 21

What can be used to test for alkenes

Answer 21

Bromine water

Question 22

When it is added to an alkane no reactrion will happen and it will stay

Answer 22

Bright orange

Question 23

If bromine water is added to an alkene it will go

Answer 23

Colourless

Question 24

Cracking is ……. Reaction - ……. By heating them

Answer 24

Thermal decomposition

Braking molecules down

Question 25

Name the 4 steps of cracking

Answer 25

1- heat the long chains to vaporize them
2- vapor passed over hot powdered aluminum oxide catalyst
3- long chain molecules split apart on the surface of the specks of catalyst
4- can also vaporize them mix with steam and then heat . Steam cracking