AS Organic

Question 1

General formula of an alkane

Answer 1

CnH2n+2

Question 2

polarity of alkanes

Answer 2

non-polar, similar electronegativities

Question 3

Explain how fracking works

Answer 3

High pressure water, sand, acid and methanol are pumped into shale rock. This breaks the shale rock so that gases are released which can flow back out into the well.

Question 4

3 opposing arguments to fracking

Answer 4

large infrastructure and traffic
may cause small earthquakes
concern about amount of water used

Question 5

conditions for thermal cracking

Answer 5

700-1200k
7000kPa

Question 6

products of thermal cracking

Answer 6

high proportion of alkenes
H2
few alkanes

Question 7

conditions for catalytic cracking

Answer 7

720K, just above atmospheric pressure, zeolite catalyst (acidic)

Question 8

time that hydrocarbons are kept in thermal cracking conditions for

Answer 8

1s

Question 9

products of catalytic cracking

Answer 9

branched alkanes, cycloalkanes, aromatic compounds

Question 10

test for alkenes

Answer 10

decolourisation of bromine solution

Question 11

7 polluting gases and their effect on the environment

Answer 11

carbon monoxide - poisonous
nitrous oxides- acid rain, smog
sulfur dioxide- acid rain
carbon particulates- asthma, cancer
unburnt hydrocarbons- greenhouse gas, smog, health risk
carbon dioxide- greenhouse gas
water vapour- greenhouse gas

Question 12

Give the equation for flue gas desulfurisation

Answer 12

CaO + 2H2O + SO2 +1/2O2 –> CaSO4*2H2O

Question 13

What are catalytic converters made from

Answer 13

honeycomb of ceramic coated with platinum and rhodium

Question 13

Explain Flue gas desulfurisation

Answer 13

slurry of calcium oxide and water is sprayed into flue gas creating calcium sulfite and then calcium sulfate (gypsum). This removes sulfur dioxide from the atmosphere and creates gypsum, a saleable product

Question 14

give 2 reactions in that catalytic converters catalyse

Answer 14

carbon monoxide + nitrogen oxide –> N2 + carbon dioxide
hydrocarbons + nitrogen oxide –> nitrogen + carbon dioxide + water

Question 15

What are the three steps to free-radical substitution

Answer 15

initiation, propagation, termination

Question 16

Explain how initiation of free-radical chain reactions happen

Answer 16

UV light is absorbed by Cl-Cl bond, breaking the bond homolytically. This produces two chlorine free radicals

Question 17

What are 2 possible propagation steps in free radical chain reactions. (With chlorine and methane)

Answer 17

Chlorine radical + methane –> HCl+ methane radical
Methane radical + Cl2 —> chloromethane + chlorine radical

Question 18

Give three possible termination steps to free radical chain reactions (With chlorine and methane)

Answer 18

Cl+Cl–> Cl2
CH3+CH3–>C2H6
Cl+CH3–> CH3Cl

Question 19

Two possible conditions to begin a free radical chain reaction

Answer 19

UV light, high temperatures

Question 20

Why are chain reactions not useful

Answer 20

they produce a large range of products

Question 21

Give the equation that Chlorine free radicals are catalysts for concerning the ozone layer

Answer 21

2O3–> 3O2