Organic chemistry

Question 1

Organic compounds

Answer 1

Carbon always forms 4 bonds and can be changed with the way it is arranged or by adding different substances like oxygen
Compounds with similar properties and the same general formula are referred to as the homologous series. This includes:
1) alkenes
2) alkanes
3) alcohols

Question 2

Alkanes

Answer 2

Alkanes are a part of the homologous series that always have the same formular: CnH2n+2 ( there are 2x as many hydrogen than carbon +2)

Question 3

Alkenes

Answer 3

All alkenes will contain at least one double carbon bond
C=C
There are said to be unsaturated and always follow the formula CnH2n (twice as many hydrogens)

Question 3

Alkenes

Answer 3

All alkenes will contain at least one double carbon bond
C=C
There are said to be unsaturated and always follow the formula CnH2n (twice as many hydrogens)

Question 4

Isomers

Answer 4

look at diagrams as reminder (dont test)

Question 5

Addition reactions of alkenes (bromination)

Answer 5

When atoms are added to the double bond, a particular type of reaction occurs. This includes:
Bromination- The bromine loses its brown- orange colour and becomes colourless when it comes in contact with a double carbon bond. This can be used to test for UNSATURATION IN A MOLECULE

Question 6

Addition reaction of alkenes (hydrogenation)

Answer 6

Hydrogenation- Adding hydrogen will make an alkane- specifically ethane, which is not useful but longer more complex alkanes can be used to make margarine
this requires a nickel catalyst/ 150C temp/ high pressure

Question 7

Polymerisation

Answer 7

A chain of small, reactive monomers
For example
Poly(propene)- Carbon double bond, 3 hydrogens and 1 CH3
Poly (vinyl chloride)- carbon double bond, 3 hydrogen 1 chlorine
Poly (tetra-fluoroethene)- carbon double bond 4 F
(no test- when drawing polymers surround the monomer in a bracket and bonds coming out of the brackets that aren’t connected to anything and add n on the outside of the bracket)

Question 8

Properties of plastics

Answer 8

insulators, lightweight, sometimes heat resistant, can be moulded into many shapes, does not rot

Question 9

Uses of plastics

Answer 9

poly ethene- bottles
poly(propene)-ropes
poly (vinyl chloride)- window frames
poly (tetra fluoroethene)- non stick pans

Question 10

How can you dispose plastics

Answer 10

Landfill- sites fill rapidly and plastics take hundreds of years to decompose
Burning- carbon dioxide and toxic fumes are released
recycling- reduced amount in landfills, uses less energy, conserves crude oil

Question 11

Alcohols

Answer 11

Another member of the homologous series- CnH(2n+1)OH
Fermentation is used to make alcohols
glucose —> ethanol + carbon dioxide OR C6H12O3 —> 2C2H5OH + 2CO2
Conditions required- 30-35C temp with pressure and yeast to use as a catalyst
ethanol is then separated via fractional distillation and used in spirits such as vodka
Ethanol is mainly made by adding water to ethane in an addition reaction but this uses crude oil

Question 12

Uses of ethanol

Answer 12

Alcoholic drinks
solvents- many substances dissolve in ethanol e.g perfume
Fuels

Question 13

Testing for alcohol

Answer 13

Potassium dichromate changes from orange to green when it comes in contact with alcohol (used in the original breath analyser