Organic Chemistry

Question 1

What is Crude Oil?

Answer 1

Crude oil is a finite resource found in rocks made up of the remains of an ancient biomass consisting mainly of plankton that was buried in mud.

Question 2

Describe how fractional distillation works

Answer 2

Crude oil is separated into fractions using fractional distillation. The crude oil is fed into the fractioning column which gets cooler as it goes up. The gases rise and then condense into liquid once they reach the level that is their boiling point. The fuels produced include Petroleum, Gasoline, Kerosene, Diesel, etc.

Question 3

How is viscosity affected by the length of the molecules in hydrocarbons?

Answer 3

The longer the molecule, the more viscous it is

Question 4

How is the boiling point affected by the length of the molecules in hydrocarbons?

Answer 4

The longer the molecule, the higher its boiling point

Question 5

How is flammability affected by the length of the molecules in hydrocarbons?

Answer 5

The longer the molecule, the less flammable it is.

Question 6

What is cracking?

Answer 6

Hydrocarbons can be cracked to produce smaller, more useful molecules. This can be done either by passing them over a hot catalyst (catalytic cracking) or mixing them with steam and heating so thermal decomposition reactions can occur (steam cracking)

Question 7

What is the test for the presence of alkenes

Answer 7

Alkenes react with bromine water, turning it from orange to colourless

Question 8

Describe the structure of alkenes

Answer 8

Alkenes are hydrocarbons with a double carbon-carbon bond. They have the general formula CnH2n. They are unsaturated because they contain two fewer hydrogen atoms than the alkane with the same number of carbon atoms.

Question 9

Name the first four Alkanes

Answer 9

Methane - CH4
Ethane - C2H6
Propane - C3H8
Butane - C4H10

Question 10

Name the first four Alkenes

Answer 10

Ethene - C2H4
Propene - C3H6
Butene - C4H8
Pentene - C5H10

Question 11

Name the first four Alcohols

Answer 11

Methanol - CH3OH
Ethanol - C2H5OH
Propanol -C3H8OH
Butanol - C4H10OH

Question 12

Name the first four Carboxylic Acids

Answer 12

Methanoic Acid - CH2O2
Ethanoic Acid - C2H2O2
Propanoic Acid - C3H6O2
Butanoic Acid -C4H8O2

Question 13

List some of the reactions of alcohols

Answer 13

• They burn in air which produces carbon dioxide and water
• They dissolve in water to form a neutral solution
• They react with sodium to produce hydrogen and a salt
• They react with oxidising agents to form carboxylic acids

Question 14

What are the main uses of the alcohols

Answer 14

Methanol: chemical feedstock
Ethanol: alcoholic drinks
All 4: fuel

Question 15

How is ethanol produced?

Answer 15

Ethanol is produced by fermenting sugar with yeast and an enzyme catalyst at about 35C.

Question 16

List some of the reactions of carboxylic acids

Answer 16

• Dissolve in water to produce an acidic solution
• Reacts with metal carbonates to produce carbon dioxide, a salt, and water
• React with alcohols (and an acid catalyst) to produce esters

Question 17

What happens in addition polymerisation?

Answer 17

Many small monomers join together to form one large polymer

Question 18

What is condensation polymerisation

Answer 18

Condensation polymerisation involves monomers with two functional groups. When these types of monomers react they join together, usually losing small molecules such as water, and so the reactions are called condensation reactions.

Question 19

Name some naturally occurring polymers

Answer 19

• Proteins (monomer = amino acid)
• Starch (monomer = glucose)
• Cellulose (monomer = glucose)