DF5- Cracking

Question 1

Define cracking

Answer 1

Term used to describe any reaction in which larger molecules are made into smaller molecules

Question 2

Why do different fractions in fractional distillation column have different boiling points?

Answer 2

Different Van Der Waals forces

Question 3

What makes catalyst inactive in cracking column?

Answer 3

Coke (carbon from decomposition of hydrocarbons) forms on catalyst surface

Question 4

In a catalytic cracker, what rises to the top?

Answer 4

-short chain hydrocarbons with low boiling points

Question 5

Define catalyst

Answer 5

Substance that speeds up a reaction but remains chemically unchanged

Question 6

Give basic features of catalysts

Answer 6

• do not undergo permanent chemical change
• may change physically (eg. surface crumbling) but can be regenerated
• only small amounts needed

Question 7

What is homogenous catalysis?

Answer 7

• when catalyst and reactants are in same physical state

Question 8

What is heterogenous catalysis?

Answer 8

• when catalyst and reactants are in different physical states

Question 9

What is a catalyst poison and how does it work?

Answer 9

Substance that stops a catalyst from functioning properly

- poison molecules are adsorbed more strongly than reactant, blocks active site