alkanes and alkenes

Question 1

general alkane formula

Answer 1

CnH2n+2

Question 2

what is a homologous series

Answer 2

a group of organic compounds which react in a similar way

Question 3

features of alkanes

Answer 3

• saturated compounds, all have single C-C carbon bonds
• first four are methane, ethane, propane, butane
• is a hydrocarbon

Question 4

what homologous series are alkanes and alkenes in

Answer 4

hydrocarbon

Question 5

features of alkenes

Answer 5

• contain one double carbon bond in their formula, meaning they are unsaturated and are therefore more reactive then alkanes
• formula is CnH2n

Question 6

what can alkenes do that alkanes cannot

Answer 6

they can form polymers

Question 7

how to tell the difference between an alkane and alkene

Answer 7

Alkenes will react with bromine water and turn it from orange/brown to colourless

Question 8

what is a functional group

Answer 8

an atom or a group of atoms which determine which determine the chemical properties of an organic compound

• e.g alkenes functional group is double bond carbons

Question 9

alkenes combustion

Answer 9

• ususally incomplete as there is not enough oxygen
  alkene + oxygen –> carbon +carbon monoxide + water

and a smokey yellow flame and less energy

Question 10

alkenes addition reaction

Answer 10

the double carbon bond will open up to leave a SINGLE BOND and a new atom is added to each carbon

Question 11

alkenes reaction with hydrogen

Answer 11

• double bond opens
• forms a saturated alkane
• this is called hydrogenation and needs a catalyst

Question 12

alkenes reaction with steam

Answer 12

• forms alcohol as water is added across the double bond
• needs a temperature over 300 degrees and needs a catalyst, this is called hydration

Question 13

alkenes reaction with halogens

Answer 13

• double bond opens
• halogen is added to one of the carbons
• this is called halogenoalkane