4.13 Alkenes

Question 1

Alkenes are joined together by

Answer 1

pi and sigma bonds so there is no rotation.

Question 2

Stereoisomerism

Answer 2

Have the same structural formula but a different arrangement in space.

Question 3

E/Z isomerism

Answer 3

Where there are different groups attached to each carbon atom of the double bond.

Question 4

Cis-Trans isomerism

Answer 4

A special case of E/Z isomerism where one of the groups is hydrogen.

Question 5

Cahn-Ingold-Prelog Rules

Answer 5

If the high priority groups are on the same side of the double bond the compound is a Z isomer. If the high priority groups are on different sides of the double bond the compound is an E isomer.

Question 6

The higher the atomic number …

Answer 6

the higher the priority.

Question 7

Reactivity of Alkenes vs Alkanes

Answer 7

Alkenes are more reactive than the Alkanes due to the double pi bonds.

Question 8

Markownikoff’s Rule

Answer 8

When a hydrogen halide reacts with an unsymmetrical alkene the hydrogen of the hydrogen halide attaches itself to the carbon of the alkene bearing the larger number of hydrogens and smaller no. of carbons.

Question 9

Polymer

Answer 9

A substance of high average molecular mass made up of small repeating units.

Question 10

Addition polymerisation

Answer 10

when the double bond breaks and bonds with other molecules to form a long chain