Organic Chem- Alkenes

Question 1

Shape and angle of a molecule with a double bone?

Answer 1

120 degrees

Trigonal planar

Question 2

Why do alkenes have weaker intermolecular Forces than their relative alkanes??

Answer 2

The double bond puts a kink in the molecule, so they can’t pack together as closely and therefore London forces are weaker

Question 3

How does double bonds affect electron density??

Answer 3

Double bonds are no more electron dense

Question 4

What does unsaturated and polyunsaturated mean??

Answer 4

Alkenes are unsaturated because the bond can open up to join other things. Polyunsaturated means an alkene chain with lots of double bonds

Question 5

How does the double bond form??

Answer 5

You get a SIGMA and PI bond forming between the two carbons
The sigma bond forms first and is two S orbitals overlapping (round circle)
The Pi bond is weaker and has two P orbitals overlapping (figure of 8) and this stops atomic rotation by fixing the bond