alkanes

Question 1

what is cracking and why is it done

Answer 1

breaking of C-C bonds in long chain hydrocarbons into smaller chain hydrocarbons as shorter chains are more valuable

Question 2

what are the conditions and products for thermal cracking

Answer 2

high temp - 1000 degrees C
high pressure - 70ATM
produces short chain alkenes

Question 3

what are the conditions and products for catalytic cracking

Answer 3

lower temp - 500 degrees C
slight pressure
zeolite catalyst
aromatic compounds

Question 4

equation for catalytic converters

Answer 4

2NO –> N2 + O2

Question 5

how is a catalytic converter efficient at its job

Answer 5

it has a honeycomb structure to maximise surface area

Question 6

what happens when sulfur impurities are burnt

Answer 6

sulfur will dissolve in the air and fall down as acid rain which kills trees and harms aquatic animals

Question 7

how is SO2 removed from the atmosphere + equation

Answer 7

CaO removes SO2 from flue gases forming CaO3
CaO + SO2 –> CaO3

Question 8

how does CO2 contribute to global warming

Answer 8

CO2 absorbs infrared radiation which emmits the energy back into the atmoshphere increasing the temp

Question 9

equation for methane + chlorine

Answer 9

CH4 + Cl2 –> CH3Cl + HCl

Question 10

initiation step for chlorination of an alkane

Answer 10

Cl2 -> 2Cl.

Question 11

2 propagation steps for the chlorination of methane

Answer 11

.Cl + CH4 –> .CH3 + HCl
.CH3 + Cl2 –> CH3Cl + Cl.

Question 12

3 termination steps for the chlorination of methane

Answer 12

.Cl + .Cl -> Cl2
.Cl + .CH3 -> CH3Cl
.CH3 + .CH3 -> C2H6

Question 13

how is crude oil seperated

Answer 13

1. oil is heated and passed through the column as a vapour
2. the fractions will condense at different heights of the column as temperature decreases as you go up the column
3. at which fraction the vapour condenses at is dependent on the boiling point of the fraction
   4.smaller molecules condense at the top of the fraction due to weak van der waal forces.

Question 14

equation for combustion of methane

Answer 14

CH4 + O2
–> CO2 + H2O

Question 15

equation for incomplete combustion

Answer 15

CH4 + O2 –> C + 2 H2O

Question 16

environmental consequence of Nitrogen oxides

Answer 16

NO is toxic and can form NO2
NO2 is toxic and forms acid rain

Question 17

environmental consequence of carbon monoxide

Answer 17

toxic -> respiratory problems

Question 18

env

Question 19

environmental consequence of carbon dioxide

Answer 19

adds to global warming

Question 20

environmental consequence of unburnt hydrocarbons

Answer 20

adds to the formation of smog

Question 21

environmental consequence of soot

Answer 21

global dimming and respiratory problems

Question 22

how is free radical substitution a chain reaction

Answer 22

a chlorine radical is regenerated which can react with more methane molecules to continue the reaction