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Chemistry: 1 > Cracking Crude Oil > Flashcards

Flashcards in Cracking Crude Oil Deck (14):
1

After you have fractionally distilled crude oil, what are you left with?

Still both long and short hydrocarbons, but just not all mixed together

2

What does 'cracking' mean?

Splitting up long-chain hydrocarbons

3

Why do we crack long-chain hydrocarbons?

To produce shorter, more useful substances

4

Long-chain hydrocarbons form ____ ____ ____ like ____, which isn't very ____ at all.

Long-chain hydrocarbons form thick, gloopy liquids like tar, which isn't very useful at all.

5

Name 3 substances produced by cracking and their uses

1. Petrol - as fuel for cars

2. Paraffin - as fuel for jets

3. Ethene - for making plastics

6

How does cracking work?

By passing a vapourised long-chain hydrocarbon over a hot catalyst

7

What kind of a reaction if cracking?

Thermal decomposition

8

Explain what is meant by the phrase 'Cracking is a thermal decomposition reaction'

It involves breaking down molecules by heating them

9

What are the 3 steps to cracking?

1. Heat the long-chain hydrocarbon to vapourise it

2. Pass the vapour over a powdered catalyst (aluminium oxide) at a temperature of about 400-700oC

3. The long-chain molecules split apart or 'crack' on the surface of the specks of catalyst

10

What are the 2 conditions needed for cracking?

1. Passed over a powdered catalyst of aluminium oxide

2. At 400oC - 700oC

11

What is an alternative way to crack long-chain hydrocarbons?

Mixing the vapour with steam at a very high temperature

12

What are the 2 main products of carcking?

1. Alkanes

2. Alkenes

13

Draw the craking of hexane (long-chain hydrocarbon) into butane (alkane) and ethene (alkene)

A image thumb
14

What is octane used for?

Petrol