C9: Crude oils and fuels

Question 1

what is a hydrocarbon

Answer 1

compound containing carbon and hydrogen only

Question 2

how is crude oil formed

Answer 2

over millions of years from the remains of ancient biomass

Question 3

what are the alkanes

Answer 3

hydrocarbons that only have single bonds

Question 4

what are the first four alkanes

Answer 4

methane,ethane,propane,butane

Question 5

what is the general formula for the alkanes

Answer 5

CnH2n+2

Question 6

how does boiling point depend on chain length

Answer 6

longer the chain, higher the boiling point

Question 7

how does viscosity depend on the chain length

Answer 7

longer the chain, higher the viscosity

Question 8

how can the different alkanes in crude oil be separated

Answer 8

fractional distillation

Question 9

what is a fraction

Answer 9

a group of hydrocarbons with similar chain lengths

Question 10

Name five useful fuels produced from fractional distillation

Answer 10

petrol, diesel oil, kerosene, heavy fuel oil, and liquefied petroleum gases

Question 11

name four useful materials produced from crude oil fractions

Answer 11

solvents, lubricants, polymers, detergents

Question 12

what is cracking

Answer 12

breaking down a hydrocarbon with a long chain into smaller molecules

Question 13

name two methods to carry out cracking.

Answer 13

steam cracking and catalytic cracking

Question 14

what are the products of cracking

Answer 14

short chain alkanes and alkenes

Question 15

what are alkenes

Answer 15

hydrocarbons with a double bond

Question 16

what are alkenes used for

Answer 16

formation of polymers

Question 17

describe the reactivity of alkenes compared to alkanes

Answer 17

alkenes are much more reactive

Question 18

how can you test for alkenes

Answer 18

alkenes turn orange bromine water colourless