Chapter 13 Alkenes

Question 1

Structure of alkenes

Answer 1

Alkenes are unsaturated hydrocarbons. have a double bond.
formula CnH2n.
cyclic alkenes and alkenes with more than one double bond do not.

Question 2

The nature of the double bond

Answer 2

double bond means one sigma bond and one pie bond. The pie bond forms by a sideways overlap of two p-orbitals, one from each carbon atom. The pie electron density is concentrated above and below the line joining the nuclei of the bonding atoms.

Question 3

The shape around a double bond

Answer 3

There are three regions of electron density around each carbon atoms.
the three regiions repel eachother so theh have 120’.
all the atoms int eh same place.

Question 4

Stereoisomers

Answer 4

have the same structural formula but a different arrangement of the atoms in space.

Question 5

E/Z isomerism

Answer 5

stereoisomerism around double bonds arises becuase rotation about the double bond is restricted and the groups attached to each carbon are fixed relative to eachother.