Alkenes

Question 1

What kind of bond does an alkene have?

Answer 1

A double carbon bond

C == C

Question 2

Why are alkenes unsaturated?

Answer 2

They can make more bonds - the double bond can open up, allowing the 2 carbon atoms to bond with other atoms

Question 3

What is the general formula for alkenes?

Answer 3

CₙH₂ₙ

Question 4

What are the first 2 alkenes?

Answer 4

Ethene (2 carbons) and Propene (3 carbons)

Question 5

What is the formula and structure of ethene?

Answer 5

C₂H₄
H                     H
     > C == C < 
H                     H
p55

Question 6

What is the formula and structure of Propene?

Answer 6

C₃H₆
     H    H             H
H--C -- C == C < 
     H                    H
p55

Question 7

How do you test for an alkene?

Answer 7

1) Adding the substance to bromine water

2) An alkene will decolourise the bromine water, turning it from orange to colourless

Question 8

Why do alkenes decolourise bromine water?

Answer 8

The double bond has opened up and formed bonds with the bromine