Unit 3: Section 3 - Alkenes and Alcohols Flashcards
(28 cards)
Why type of hydrocarbon is an alkene?
An unsaturated hydrocarbon.
What does unsaturated mean?
It means they are able to form more bond under the correct conditions.
Why do carbon-carbon double bonds have a high electron density?
Because there are two pairs of electrons present.
What are electrophiles?
Electron-pair acceptors
What are polymers formed from?
Monomers
How are addition polymers made?
When monomers join together to make long chains.
What are polyalkenes?
Addition polymers made from alkenes.
Why are addition polymers unreactive?
They are saturated and the main carbon chain is non-polar.
What forces hold polyalkene chains together?
Van der Waals forces
____, ________ polyalkene chains tend to be ______ and ______.
_____, _________ polyalkene chains tend to be _______ and ______________.
Long Straight Strong Rigid Short Branched Weaker More flexible
What does a plasticiser do and how does it work?
They make polymers more flexible by pushing polymer chains apart and reducing the strength of the intermolecular forced between the chains.
What is PVC used to make? (2)
- Drainpipes
* Window frames
What is plasticised PVC used to make?
- Electrical cable insulation
- Flooring tiles
- Clothing
How do you determine whether an alcohol is primary, secondary or tertiary?
By looking at which carbon the hydroxyl group is bonded to.
What is a biofuel?
A fuel that’s made from biological material that’s recently died.
What are the advantages of using biofuels? (2)
- Biofuels are renewable energy sources. Unlike fossil fuels, biofuels won’t run out, so they’re more sustainable.
- Biofuels are classed as carbon neutral so they produce carbon dioxide which is then absorbed by plants.
What does carbon neutral mean?
Carbon neutral means that they do not contribute to or remove the carbon dioxide in the atmosphere.
What are the disadvantages of using biofuels? (2)
- Petrol car engines have to be modified to use fuels with a high ethanol concentration.
- When land is used to grow crops for fuel that land isn’t being used to grow food.
How do you oxidise alcohol? (2)
- By burning them.
2. By using an oxidising agent such as acidified potassium dichromate (VI)
What do determines what an alcohol oxidises to?
The structure of the alcohol
Which type of alcohol oxidises to what?
- Primary alcohols oxidise to aldehydes and then carboxylic acids.
- Secondary alcohols oxidise to ketones.
- Tertiary alcohols do not oxidise.
Why do tertiary alcohols not oxidise easily?
They don’t react with potassium dichromate. You can only oxidise them by burning them.
How do you oxidise a secondary alcohol?
Using potassium dichromate under reflux.
How can you distinguish between aldehydes and ketones?
- Fehling’s solution
* Tollens’ reagent
