3.3.2 alkanes

Question 1

what are alkanes?

Answer 1

saturated hydrocarbons

Question 2

define hydrocarbon

Answer 2

containing hydrogen, oxygen and carbon only

Question 3

what is petroleum?

Answer 3

mixture of alkane hydrocarbons which can be separated by fractional distillation

Question 4

what is cracking

Answer 4

breaking c-c bonds

Question 5

Thermal cracking conditions?

Answer 5

high pressure (7000kPa)
High temperature (400-900 Celsius)

Question 6

Products of thermal cracking

Answer 6

alkenes (mainly) for polymers/ethanol.

hydrogen for haber/margarine

Question 7

catalytic cracking conditions

Answer 7

low pressre
high temperature 450
zeolite catalyst

Question 8

products of catalytic cracking

Answer 8

branched and cyclic alkanes

aromatic hydrocarbons

Question 9

is combustion of alkanes exo/endo?

Answer 9

exothermic

Question 10

what does internal combustion engine produce?

Answer 10

NOx, CO, C and unburned hydrocarbons

Question 11

How are pollutants removed?

Answer 11

catalytic converters

Question 12

Catalytic converters metals?

Answer 12

platinum, palladium, rhodium

Question 13

Removal of CO/NO equation

Answer 13

2CO + 2NO = 2CO2 +N2

Question 14

Removal of unburned hydrocarbons +No

Answer 14

= CO2 +N2 +9H20

Question 15

flue gas desulphurisation equation

Answer 15

SO2 + CaO = CaSO3

Question 16

conditions needed for alkane c-c bond to break

Answer 16

UV light

Question 17

mechanism for alkane to halogenalkane?

Answer 17

free radical substitution

Question 18

stages of FRS?

Answer 18

initiation propagation, termination

Question 19

why is it called a chain reaction

Answer 19

continuing generating free radicals

Question 20

why is FRS not really useful?

Answer 20

large variety of products possible.