4.1.3 Properties of Alkenes

Question 1

what are alkenes?

Answer 1

unsaturated hydrocarbons containing a carbon carbon double bond comprising a π-bond and a σ-bond

Question 2

what is a π-bond?

Answer 2

sideways overlap of adjacent p-orbitals above and below the bonding C atoms

Question 2

what types of bond do alkenes have?

Answer 2

σ and π

Question 3

what is a σ-bond?

Answer 3

overlap of orbitals directly between the bonding atoms

Question 4

what type of rotation do alkenes have?

Answer 4

restricted rotation

Question 5

why do alkenes have restricted rotation?

Answer 5

due to the π-bond (which alkanes do not have)

Question 6

what bond angle do alkenes have?

Answer 6

120

Question 7

what shape do alkenes have?

Answer 7

trigonal planar

Question 8

why do alkenes have this shape?

Answer 8

this shape minimises electron electron repulsion

Question 9

what homologous series are they apart of?

Answer 9

series with the general formula with CnH2n

Question 10

what are electrophiles?

Answer 10

species that are electron pair acceptors (attracted to electron dense areas)

Question 11

why are electrophiles attracted to alkenes?

Answer 11

they are attracted to the highly electron dense double bond

Question 12

what types of bond make up a carbon carbon double bond?

Answer 12

σ and π

Question 13

what is a single covalent bond made up of?

Answer 13

σ

Question 14

what can be used to identify an alkene double bond or other unsaturated compounds?

Answer 14

bromine water

Question 15

what is the colour change when an alkene is tested with bromine water?

Answer 15

orange to colourless

Question 16

why does bromine experience a colour change when reacted with an alkene?

Answer 16

bromine forms bonds with the carbon carbon double bond, therefore it becomes saturated