organic chemistry

Question 1

combustion of alcohols

Answer 1

produce CO2 and water
eg ethanol:
C2H5OH + 3O2 = 2CO2 + 3H2O

Question 2

alkanes reaction with halogens

Answer 2

chlorine and bromine react with alkanes under UV to form haloalkanes
substitution reaction, so H(halogen) is produced
eg. bromine and methane
CH4 + Br2 = CH3Br + HBr

Question 3

cracking

Answer 3

to split longer alkanes into shorter alkanes and an alkene
thermal decomposition
shorter alkanes used for fuels
alkenes used for polymers
conditions:
- vaporised hydrocarbons passed over powdered alumina or silica (catalyst).
- 600-700 degrees

Question 4

isomers

Answer 4

different displayed formula but same molecular formula

Question 5

addition polymers

Answer 5

additon polymerisation needs high temps and a catalyst
monomers have brackets with an n before
repeating unit has brackets (shows polymer) and an n after
most addition polymers are inert, because of the carbon to carbon bonds which are very strong
takes a long time for them to biodegrade
burning them can released toxic gases

Question 6

why does melting point increase with mr?

Answer 6

surface area of molecule is higher and there are more electrons so the intermolecular forces are stronger, requiring more energy to overcome