1alkenes

Question 1

all alkenes contain a

Answer 1

double carbon bond

Question 2

molecular formula of ethene

Answer 2

C2H4

Question 3

molecular formula of propene

Answer 3

C3H6

Question 4

alkenes are

Answer 4

a homologous series of hydrocarbon compounds with at least one double bond between two of the carbon atoms on the chain

Question 5

general formula for alkenes are

Answer 5

CnH2n

Question 6

alkenes are more desirable than alkanes as they are

Answer 6

more reactive due to the presence of there carbon double bond so they can take part in reactions in which alkanes can’t, making them more useful than alkanes

Question 7

alkenes are used to

Answer 7

make polymers and are the starting materials in the production of many other chemicals

Question 8

bromine water test

Answer 8

Alkanes and alkenes have different molecular structures
All alkanes are saturated and alkenes are unsaturated
The presence of the C=C double bond allows alkenes to react in ways that alkanes cannot
This allows us to tell alkenes apart from alkanes using a simple chemical test called the bromine water test

Question 9

when bromine water is added to an alkane

Answer 9

it will remain as an orange solution as alkanes do not have double carbon bonds so the bromine remains in solution

Question 10

when bromine water is added to an alkene

Answer 10

the bromine atoms add across the double carbon bond hence the solution no longer contains free bromine so it loses its colour