C1.5 Flashcards
Describe the process of cracking
Long chain alkanes are heated with a catalyst
What is an alkene?
It’s a hydrocarbon with at least 1 double bond
What is the general formula for an alkene?
CnH2n
What happens when alkenes react with bromine water?
The bromine water changes from orange to colourless
Draw a diagram representing the process of polymerisation of ethene
H H H H H H
| | | | | |monomers C=C + C=C + C=C ->
| | | | | |
H H H H H H
ethene ethene ethene
H H H H H H
| | | | | |
polymer -C-C-C-C-C-C-
| | | | | |
H H H H H H
polyethene
What uses do we have for polymers?
- Plastic bags
- Plastic bottles
- Coating on electricity wires
- Buckets + Crates
- Window frames
- Nonstick coating on pans
Why is it important to recycle polymers?
- Plastics are not biodegradable
- Not recycling creates a build up in landfill sites
What is cracking and why is it necessary?
It is when a large alkane is made into a smaller alkane and an alkene.
It’s necessary because there is more demand for smaller, more useful hydrocarbons
Name and describe 3 smart polymers
- Lycra, a stretchy material used to make clothing. Doesn’t get affected from sweat and detergents
- Kevlar, an artificial fibre used to make body armour. It’s flexible, strong and tough
- Gore-Tex, an artificial fabric that keeps the rain out but lets sweat pass through. It’s waterproof and ideal for sports and outdoor clothing
What are the two methods of producing ethanol?
- By reacting steam with ethene at a moderately high temperature and pressure in the presence of a catalyst, phosphoric acid
- Fermentation, which is carried out in a solution using yeast at about 37*C
What is the word equation for producing alcohol from ethene?
Ethene + steam ——–> ethanol
Phosphoric acid
What is the word equation for producing ethanol from sugar?
Sugar–> ethanol + carbon dioxide
Yeast
What is the advantage of using fermentation?
-Uses corn and sugar cane (renewable resources)
What are the disadvantages of fermentation?
- Is a batch process, which needs a lot of workers
- Produces impure ethanol, and is purified by distillation
- Needs a temperature of 30-40*C
- Is a slow reaction
What are the advantages of using hydration?
- Is a continuous process so is less labour intensive
- Produces pure ethanol
- Is a fast reaction
