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17 Cards in this Set
- Front
- Back
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What are the products of cracking a long hydrocarbon? |
A smaller alkane and an alkene. |
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What is the positive test for an alkene? |
Bromine water turns from orange to colourless. |
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Why do we crack long hydrocarbons? |
To make more useful shorter chain hydrocarbons, and alkenes for plastics. |
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What are the two processes of cracking? |
1. Mix with steam at high temperature. 2. Pass vapours over a hot catalyst. |
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What are plastics made of? |
Polymers. |
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What is a polymer? |
Large molecule made of lots of monomers joined together. |
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What does a monomer need to become a polymer? |
A double bond e.g. alkene |
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What happens during polymerisation? |
Double bond in monomer opens up, replaced by single bonds to join to more monomers. |
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What is a smart polymer? |
Polymers suited to a specific task, which may change due to changes in their environment. |
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Name some examples of smart polymers. |
Hydrogels. Light - sensitive plasters. Shape memory polymers - stitches. Fillings for teeth. |
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What are the problems caused by non-biodegradeable plastics? |
Ugly rubbish, can harm wildlife, takes up space in landfill sites, takes hundreds of years to decompose (rot). |
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What does biodegradeable mean? |
Can be broken down by living things, usually microorganisms in soil. |
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How can we make plastics biodegradeable? |
Using cornstarch in the polymers, which the microorganisms can eat. |
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What are the problems with making plastics biodegradeable? |
Uses up food crops. Destruction of rainforests/habitats to create more farmland. |
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What are the two ways to make ethanol? |
1. Fermentation - using sugar and yeast 2. Hydration - using ethene and steam |
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What is an advantage and disadvantage of fermentation? |
Advantage - Renewable, uses plants. Disadvantage - produces CO2 (greenhouse gas) |
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What is an advantage and disadvantage of hydration? |
Advantage - continuous process. Disadvantage - requires lots of energy, non-renewable, uses ethene from crude oil. |
