cracking

Question 1

what are the 2 types of cracking

Answer 1

thermal cracking
catalytic cracking

Question 2

what 3 products are formed by catalytic cracking

Answer 2

• aromatic compounds
• branched alkanes
• cycloalkanes

Question 3

why are branched alkanes and cycloalkanes used in cars

Answer 3

the burn more efficiently in the internal combustion engine of a car

Question 4

if the products catalytic cracking decolourise bromine solution what does this show the product contains

Answer 4

alkenes

Question 5

what type of catalyst does catalytic cracking use and what is it made up of

Answer 5

a zeolite catalyst

made up of silicon dioxide and aluminium oxide

Question 6

what structure do zeolite catalysts have

Answer 6

honeycomb structure
large SA

Question 7

what temperature is needed for catalytic cracking

Answer 7

720K

Question 8

what pressure is needed for catalytic cracking

Answer 8

pressure higher than atmospheric

Question 9

what temperature is needed for thermal cracking

Answer 9

700-1200 K

Question 10

what pressure is needed for thermal cracking

Answer 10

7000kPa

Question 11

what products does thermal cracking form

Answer 11

forms an alkene and an alkane

Question 12

what happens when the c-c is broken during thermal cracking

Answer 12

breaks causing 1 electron from the pair in a covalent bond to go to each of the carbon atom

2 chains produced end in carbon atom with unpaired e- (these are called FREE RADICALS, these are highly reactive)