Cracking

Question 1

Why do we do cracking

Answer 1

from crude oil we get more of the heavier (long chain) fractions than we can use, and less of the lighter (short chain) fractions than we need - cracking solves this as the long chain alkanes are split giving shorter chain alkanes and shorter chain alkenes

Question 2

Catalyst definition

Answer 2

catalysts speeds up rate of reaction without getting used up by providing an alternative route with a lower activation energy. They emerge chemically unchanged but they may change physically. They do not alter the how much product is given they only alter the rate its produced

Question 3

Catalysis definition

Answer 3

process of speeding up a reaction using a catalyst

Question 4

2 types of catalysts

Answer 4

heterogeneous and homogeneous

Question 5

Heterogeneous catalyst definition

Answer 5

the catalyst is in a different state to the ractants

Question 6

How does a heterogeneous catalyst work

Answer 6

th reactions hapens on the catalyst surface:
1. the reactant molecules are adsorbed onto the catalyst surface - make bonds with it which weakens the bonds within the reactant molecules.
2. bonds within the reactant molecules break which takes less energty as the bonds are weakened hense the activiation energy has been lowered.
3. new bonds form making the product molecules
4. the product molecules leave the catalyst surface (desorbs)