fractional distillation and cracking

Question 1

what is crude oil

Answer 1

fossil fuel made from remains of ancient biomass

Question 2

what are the first 4 alkenes

Answer 2

methane
ethane
propane
butane

Question 3

formula to work out alkene

Answer 3

Cn H2n+2

Question 4

hydrocarbon

Answer 4

compound only with hydrogen and carbon

Question 5

what is the use of petrol

Answer 5

fuel for cars

Question 6

what is the use of naphtha

Answer 6

used to manufacture chemicals

Question 7

what is the use of bitumen

Answer 7

used for laying roads

Question 8

what is the use of kerosene

Answer 8

fuel for aircrafts

Question 9

what is the use for diesel

Answer 9

fuel for cars, vans and lorries

Question 10

what is fractional distillation

Answer 10

separate components with different condensing temperatures in a mixture

Question 11

where does fractional distillation take place

Answer 11

fractionating column

Question 12

what is cracking

Answer 12

breaking down large molecules in to smaller more useful ones

Question 13

where does cracking take place

Answer 13

oil refinery in steel vessels

Question 14

how does cracking work

Answer 14

heavy fractional of distilled crude oil is heated to vaporise hydrocarbons

Question 15

what happens to the vapour in cracking

Answer 15

passed over a hit catalyst
mixed with steam and heated ti a very high temp

Question 16

what is cracking an example of

Answer 16

thermal decomposition

Question 17

why is cracking so important

Answer 17

to meet demands for fuels

Question 18

how can large hydrocarbon molecules be cracked in an oil refinery

Answer 18

hydrocarbon vapours passed over a hot catalyst

Question 19

unsaturated hydrocarbon

Answer 19

hydrocarbon containing at least 1 C=C double bond

Question 20

type of bonding in hydrocarbons

Answer 20

covalent

Question 21

what properties would you expect from a hydrocarbon

Answer 21

low boiling point due to covalent bond (molecules)

Question 22

How many bonds does each hydrogen atom need to make?

Answer 22

1

Question 23

How many bonds does each carbon atom need to make?

Answer 23

4

Question 24

why are hydrocarbons good fuels?

Answer 24

with OXYGEN exothermically producing CO2 and steam

Question 25

why are hydrocarbons better fuels that wood /coal?

Answer 25

don’t make ash

so there is no need to clean out the combustion chamber

Question 26

what problems are associated with using hydrocarbons as fuel?

Answer 26

CO2 is a greenhouse gas

climate change

Question 27

how many joules of energy does 1 mole go petrol release
(assuming complete combustion)

Answer 27

6770kJ

Question 28

define a FUEL

Answer 28

substance that releases energy when burnt

Question 29

properties of alkanes

Answer 29

saturated
no double bonds

Question 30

properties of short chain hydrocarbons

Answer 30

low BP and MP
very flammable
low viscosity

Question 31

word equation for complete combustion

Answer 31

Fuel +oxygen - >carbon dioxide + water

Question 32

when are alkenes formed

Answer 32

when we crack large alkanes

Question 33

uses of alkenes

Answer 33

used to make polymers and plastic

Question 34

do we use alkenes for fuel

Answer 34

no

Question 35

test for alkenes

Answer 35

bromine water

positive test becomes colourless
negative test stays orange

Question 36

how to draw alkenes

Answer 36

1 double bond between the carbons