Alkenes 3.3.4

Question 1

what’s the general formula for alkenes

Answer 1

CnH2n

Question 2

what is an alkene

Answer 2

unsaturated hydrocarbon ( has a C=C)

Question 3

Why is it different to an alkane

Answer 3

It’s much more reactive than alkanes

Question 4

what are some of the physical properties of alkenes

Answer 4

Insoluble in water
melting point and boiling point increased in chain length so VDW forces are stronger if the chain is longer

Question 5

what is the test for an alkene

Answer 5

Shake with bromine water
orange to colourless

Question 6

why is the double bond important in creating E-Z isomers

Answer 6

Double bond caused a restricted rotation

Question 7

define stereoisomerism

Answer 7

same structural forumla but atoms / groups have different spacial arrangements

Question 8

what are the conditions for electrophilic addition reaction of an alkene to a dihaloalkane

Answer 8

Br2
Room temp
Electrophile

Question 9

what are the conditions needed for electrophilic addition reaction of an alkene to a haloalkane

Answer 9

HBr
Room temp

Question 10

EQ : if major and minor product former , explain why the two products are formed in different amounts (2)

Answer 10

The major product is formed via a tertiary carbocation intermediate and minor product is a secondary carbocation intermediate.
The major product is more stable