Products from Oil

Question 1

What is cracking?

Answer 1

The process of breaking large hydrocabons down into smaller hydrocarbons

Question 2

How can cracking be done?

Answer 2

In two ways:

1. By heating a mixture of hydrocarbon vapours and steam to a very high temperature
2. By passing hydrocarbon vapours over a hot catalyst

Question 3

What happens during cracking?

Answer 3

Thermal decomposition reactions produce a mixture of smaller molecules.

These smaller molecules are alkanes and alkenes

Question 4

What are alkanes with smaller molecules useful for?

Answer 4

Fuels

Question 5

What is the general formula for alkanes and what are they?

Answer 5

Saturated hydrocarbons

C_<em>n</em>H_2n+2

Question 6

What is the general formula for alkenes and what are they?

Answer 6

Unsaturated hydrocarbons - they contain a double bond

C_nH_2n

Question 7

What can bromine water be used to test for?

Answer 7

Alkenes - they turn it from orange to colourless

Question 8

How can different mixtures of alkenes and alkanes be produced?

Answer 8

By using different hydrocarbons

By changing the conditions of the reaction

Question 9

What are plastics made from?

Answer 9

Polymers

Question 10

What are polymers?

Answer 10

Very large molecules made from lots of the same very small molecule (monomers) joined together

Question 11

How are polymers made?

Answer 11

Polymerisation (the reaction of monomers to make polymers)

Question 12

What happens during the polymerisation reaction to produce polymers?

Answer 12

The double bond in each of the alkenes are broken and used to join monomers together in long chains

Question 13

Draw a diagram showing the polymerisation of ethene

Answer 13

Question 14

What is formed when propene is polymerised?

Answer 14

Poly(propene)

Question 15

Give some examples of uses of plastics

Answer 15

• Bags
• Bottles
• Containers
• Toys
• Furniture

Question 16

Why can polymers be made from alkenes but not alkanes?

Answer 16

Alkanes are saturated and do not contain a double bond.

This means that it cannot be broken and used to join monomers/molecules together to form long chains

Question 17

Give some examples of new and useful polymers

Answer 17

• Polymers to replace mercury in dental fillings
• Light-sensitive polymers to be used in plasters to cover wounds so plasters can be easily removed
• Hydrogels are polymers that can trap water and have many uses including dressings for wounds
• Shape-memory polymers change back to their original shape when temperature/other conditions are changed. Can be used as stitches that revert back to their original shape when heated to body temp.
• Fibres used to make fabrics can be coated with polymers to make them waterproof + breathable
• Plastic used to make drinks bottles can be recycled to make polyester fibres for clothing, pillow filling, and duvets

Question 18

What are smart polymers?

Answer 18

Polymers that change in response to their environment

E.g. shape-memory polymers

Question 19

Complete the sentence:

Many polymers are not…

Answer 19

…biodegradable

Question 20

What does biodegradable mean?

Answer 20

Materials that can be broken down by microorganisms

Question 21

What are the drawbacks of non-biodegradable plastics?

Answer 21

• Unsightly
• Can harm wildlife
• Take up space in landfill sites

Question 22

How are plastics made more environmentally friendly?

Answer 22

• Biodegradable - microorganisms break them down on contact with soil
• Non-biodegradable plastics have cornstarch added. Microorganisms break down the cornstarch, also breaking down the plastic into smaller pieces that can be mixed with soil/compost
• Biodegradable plastics can be made from plant material. E.g. polymer made from cornstarch that’s used as food packaging
• Can be recyled - however many different types so sorting is hard

Question 23

What is the formula for ethanol?

Answer 23

C₂H₅OH

Question 24

How can ethanol be produced?

Answer 24

Fermentation or hydration

Question 25

Describe how fermentation is used to produce ethanol

Answer 25

* Sugar can be fermented using yeast * The enzymes in the yeast convert the sugar into ethanol + CO₂ * This method is used to make alcoholic beverages

Question 26

Describe how hydration is used to produce ethanol

Answer 26

* Can be made through the hydration of ethene * The ethene is obtained from crude oil by cracking * It is then reacted with steam at a high temperature in the presence of a catalyst

Question 27

What are the advantages and disadvantages of producing ethanol using fermentation?

Answer 27

* It uses a **renewable** resource, sugar from plants * Is done at **room temperature** HOWEVER: * Only produces **small amounts** (batch production) * Produces **dilute, aqueous solution** of ethanol, meaning it must be seperated from the solution using fractional distillation to give pure ethanol * Is **slower** * Produces CO₂ (albeit small amounts)

Question 28

What are the advantages and disadvantages of producing ethanol using hydration?

Answer 28

* Can run **continuously** * Produces **pure ethanol** HOWEVER: * Uses a **non renewable** resource, crude oil * Requires a **high temperature** (and high energy)