6.25 - Alkenes and their bonding

Question 1

What is the main difference between an alkane and an alkene?

Answer 1

An alkene has a C=C bond, whereas an alkane doesn’t

Question 2

Are alkenes more or less common than alkanes?

Answer 2

Less common

Question 3

What is a solution to this?

Answer 3

They can be made from cracking long chain alkanes

Question 4

What is the general formula for alkenes?

Answer 4

CnH2n

Question 5

What is different about cyclic alkenes?

Answer 5

They don’t have the same general formula - they have 2 fewer hydrogens

Question 6

What is a sigma bond?

Answer 6

A bond formed when electron orbitals overlap axially (end-on)

Question 7

What is a pi bond?

Answer 7

A bond formed when electron orbitals overlap sideways

Question 8

In a diagram of ethene, where is:

• The sigma bond
• The pi bond

Answer 8

Sigma bond is the line between the two carbons

The pi bond is either side of this line, represented by two clouds where the p orbitals have overlapped

Question 9

What type of bond are sigma and pi bonds?

Answer 9

Covalent