Chapter 1 Ethelene And Addition Polymers

Question 0

Identify some fractions produced from fractional distillation of of petroleum

Answer 0

Refinery gas (1-4 carbon chain)
Petrol (5-8 carbon chain)
Naphtha (7-13 carbon chain)
Kerosene (11-16 carbon chain)
Diesel oil (15-18 carbon chain)
Lubricants and paraffin waxes (16-40 carbon chain)
Residue (>40 carbon chain)

Question 1

Describe the composition of petroleum

Answer 1

Petroleum is a mixture of crude oil and natural gas

Question 2

Define fractional distillation

Answer 2

The process of separating out a mixture of substances by taking each fraction to slightly below the volatility in each column and letting the others boil into the next column

Question 3

What are the sources of ethylene (ethene)

Answer 3

Fractional distillation, thermal cracking of natural gas, cracking of naphtha.

Question 4

Describe the process of cracking to produce ethylene

Answer 4

Heating of larger hydrocarbons to form free radicals then cooling the radicals in the presence of each other to form ethene. Some times catalysts are used to lower the activation energy meaning you don’t have to heat up the hydrocarbons to as high a tempreature.

Question 5

What homologous group does ethylene belong to?

Answer 5

Alkenes

Question 6

Describe the functional group of an alkene

Answer 6

All have a double bond as their functional group

Question 7

Molecular formula for ethane

Answer 7

C2H6

Question 8

Molecular formula of ethylene

Answer 8

C2H4

Question 9

The molecular formula for ethyne

Answer 9

C2H2

Question 10

Why is ethene used more in industry then ethane?

Answer 10

Ethene although it shares similar properties with ethane has a double bond that allows the formation of polymer units like polyethylene

Question 11

Substitution reaction

Answer 11

A substitution reaction is one in which the an atom in a molecule is swapped for another

Question 12

What is an addition reaction?

Answer 12

A reaction that combines many monomers together in a polymer that given sufficient resources could grow infinitely large

Question 13

Define monomer

Answer 13

A monomer is a sub unit of a polymer

Question 14

Define polymer

Answer 14

A long chain macromolecule that is composed of repeating sub units called monomers

Question 15

Why is ethylene a monomer?

Answer 15

Because the double bond allows it to deform repeating units of hydrocarbons with each other

Question 16

Name some monomers

Answer 16

Starch, ethene, benzoyl peroxide, vinyl chloride.

Question 17

Name some polymers

Answer 17

Polyethylene, polyvinyl chloride, glucose.

Question 18

Justify why polyethylene is a important polymer.

Answer 18

Polyethylene is used in many containers in different forms due to the different properties that it has depending o the structure of the polymer chain. Branching polymers are less dense and are used in plastic bags, non branching polymers as more dense and brittle and are used in containers like milk cartons, cross branching polymers are very brittle as well as very tough and so are used as bottle caps.

Question 19

Outline production of polyethylene

Answer 19

Polyethylene is formed in two ways

1. Initiation :uses initiator free radicals to break the bonds in ethene molecules allowing it to connect with other ethene free radicals.
2. Catalytic surfacing :uses a catalyst called chromium oxide to give a surface to allow the bonds to break and connect with others

Question 20

How do ethene radicals assist in the formation of polymers?

Answer 20

Ethene radicals are reactive on both sides of the molecule and so will react with other free radicals on either side

Question 21

Why is it important to monitor the temperature in a polyethylene reaction vessel?

Answer 21

The heat may be sufficient to break the bonds in the product and will form ethylene from the free radicals it produces.