C10: Other Products from Crude Oil

Question 1

Cracking

Answer 1

The reaction used to break down large unusable hydrocarbons into smaller, more useful ones.

Question 2

Conditions for cracking

Answer 2

Passed over a hot catalyst/ mixed with steam

Heated to a high temperature (e.g. 500 degrees)

Question 3

Alkenes

Answer 3

Unsaturated hydrocarbons which contain carbon-carbon double bonds. General formula CnH2n

Question 4

Test for alkenes/ unsaturated carbon-carbon double bonded molecules

Answer 4

Bromine water turns from orange to colourless.

Question 5

Hydration

Answer 5

A reaction in which water is chemically added to a compound.

Question 6

What is produced by cracking?

Answer 6

alkanes to be used as fuel, and alkenes.

Question 7

Monomers

Answer 7

Small reactive molecules that react together in repeating sequences to form a very large molecule (a polymer).

Question 8

Properties of poly(ethene)

Answer 8

> Easy to shape
Strong
Transparent

Question 9

Properties of poly(propene)

Answer 9

> Strong

> Tough

Question 10

Polymerisation

Answer 10

When alkene molecules join together as the double bond between the carbon atoms ‘opens up’ and the thousands of molecules are able to join together.

Question 11

What do the properties of a polymer depend on?

Answer 11

> The monomers used to make it.

> The conditions chosen to carry out the reaction.

Question 12

Low Density poly(ethene)

Answer 12

> Formed using high pressure and trace oxygen.

> Polymer chains are joined together at random and they can’t pack together, hence its lower density.

Question 13

High Density poly(ethene)

Answer 13

> Formed using a catalyst at 50 degrees with a slightly raised pressure.
Creates straight, closely packed chains that give it a higher density.
It is stronger and less prone to melting that LD poly(ethene).

Question 14

Thermosoftening Polymers

Answer 14

Polymers that form plastics which can be softened by heating, then remoulded into different shapes as they cool down and set.

Question 15

Thermosetting Polymers

Answer 15

Polymers that can form extensive cross-linking between chains, resulting in rigid materials which are heat resistant.

Question 16

What sort of bonds are used in polymer chains?

Answer 16

Very strong covalent bonds.

Question 17

Bonding in Thermosoftening Polymers

Answer 17

> Forces between the polymer chains are weak, and broken by heating.
When the polymer cools down again, it is brought back together by intermolecular forces.

Question 18

Bonding in Thermosetting Polymers

Answer 18

> Monomers create covalent bonds between the polymer chains when it is forms to create its shape and structure.
Covalent bonds are strong, and stops the polymer from melting or changing shape.
Polymer will not melt, will char instead at high enough temps.

Question 19

Which is more reactive- alkanes or alkenes?

Answer 19

The C-C double bond in alkenes make them much more reactive.

Question 20

Smart Polymers

Answer 20

Polymers that change in response to changes in their environment.

Question 21

2 ways to speed up the decomposition of polymers:

Answer 21

> Building cornstarch molecules into the plastic allows the microorganisms in soil to break up the plastic more quickly.
Polymers are being made from plant material.