Alkenes and Ethanol

Question 1

What do alkenes have?

Answer 1

A C=C double bond.

Question 2

What is the general formula for alkenes?

Answer 2

CnH2n

Question 3

What are the first two alkenes?

Answer 3

Ethene and propene

Question 4

Are alkenes saturated or unsaturated?

Answer 4

Unsaturated, because the C=C double bond can open up and form bonds.

Question 5

How can you test for the presence of an alkene?

Answer 5

Add the substance to bromine water. If an alkene is present, the bromine water will go from orange to colourless. This is because the the double bond has opened up and formed bonds with the bromine.

Question 6

How can ethanol be produced with steam?

Answer 6

Ethene can be HYDRATED with STEAM, in the presence of a CATALYST, to make ethanol.

Question 7

What are the pros and cons of making ethanol with steam?

Answer 7

Pros:Quite cheap because ethene is quite cheap and not a lot of ethene is wasted.
Cons: Ethene is non-renewable as it is from crude oil, it will become very expensive.

Question 8

How can ethanol be produced from renewable resources?

Answer 8

Sugar can be fermented:

Sugar—->carbon dioxide + ethanol

Question 9

What are the pros and cons of producing ethanol via fermentation?

Answer 9

Pros: Sugar is a renewable resource, it needs a lower temperature and simpler equipment than ethene, can be quite a cheap fuel.
Cons: It has to be distilled and purified. CO2 is released