2 Alkanes

Question 1

alkanes

Answer 1

saturated hydrocarbons

Question 2

what is petroleum?

Answer 2

a mixture consisting of alkane hydrocarbons that can be seperated by fractional distillation

Question 3

fractional distillation

Answer 3

Crude oil is heated to around 400oC. The vapour rises, cooling and condensing at different temperatures depending on the boiling point of that alkane.

Question 4

cracking

Answer 4

breaking C-C bonds in alkanes

Question 5

thermal cracking

Answer 5

takes place at high temperature (800oC) and high pressure (700kPa)
produces a high percentage of alkenes

Question 6

catalytic cracking

Answer 6

takes place at a slight pressure, high temperature and in the presence of a zeolite catalyst
produces mainly motor fuels (branched alkanes) and aromatic hydrocarbons

Question 7

fracking

Answer 7

drilling into shale and forcing high pressure water into the cracks. This releases trapped gases which are used as natural gas

Question 8

combustion of alkanes

Answer 8

can be complete or incomplete

Question 9

what does the internal combustion engine produce?

Answer 9

NOx (causes acid rain)
CO (poisonous)
SO2 (due to sulfur impurities, causes acid rain)
CO2, H2O
Carbon particulates

Question 10

catalytic convertor

Answer 10

made of platinum or rhodium in a honeycomb (so a large surface area)
converts NO and CO in to CO2 and N2

Question 11

flue gas desulfurisation

Answer 11

calcium carbonate or calcium oxide added to SO2 impurities, producing CaSO4 and CO2/H2O

Question 12

reaction of alkanes with chlorine

Answer 12

free radical substitution
under UV light
Initiation: Cl2 →Cl*
Propagation: CH4 + Cl→ CH3 + HCl
Termination: Cl + Cl→ Cl2
CH3 + Cl→CH3Cl
*CH3 + *CH3→CH3CH3