4.5 Alkenes

Question 1

What is the general formula

Answer 1

CnH2n

Question 2

what is the difference between alkanes and alkenes

Answer 2

alkanes have singular bonds
alkenes have double bonds

Question 3

what is the molecular formular for Ethene

Answer 3

C2h4

Question 4

what is the molecular formular for Propene

Answer 4

C3H6

Question 5

what is the molecular formular for Butene

Answer 5

C4H8

Question 6

what is the molecular formular for Pentene

Answer 6

C5H10

Question 7

are alkenes referred to as saturated or unsaturated

Answer 7

unsaturated
-because they have a double bond

Question 8

How do alkenes react with bromine

Answer 8

by breaking the double bonds and adding bromine atoms in

Question 9

what type of reaction does alkene have

Answer 9

Addition

Question 10

what conditions does addition need

Answer 10

• no need for UV light because alkenes are more reactive than alkanes
• it works with pure bromine liquid or bromine water (which is orange)
• The reaction turns from orange to colourless (because bromine is used up in the reaction)

Question 11

what is the reaction between bromine and alkenes used for

Answer 11

test for the double bond in unsaturated compounds
- stays orange- no c=c saturated
- turns colourless c=c bond present (unsaturated)

Question 12

what are additional polymers

Answer 12

• inert
• chemically unreactive
• don’t break down very easy

Question 13

what are the options for disposal of unwanted polymers

Answer 13

1. re use it
2. recycle
3. incinerate it and use the energy for electricity
4. chuck it onto landfill