Organic chemistry

Question 1

what is the homologous series

Answer 1

a family of similar compounds with similar chemical properties due to the presence of the same functional group

Question 2

what is a functional group

Answer 2

group of atoms which are bonded in a specific arrangement that is responsible for the characteristic reactions of each member

Question 3

describe cracking in the refinery

Answer 3

1. long-chain hydrocarbon is heated to vapourise it
2. the vapour is usually passed over a hot catalyst
3. thermal decomposition

Question 4

what happens when alkane is cracked

Answer 4

the number of atoms of C + H in the products is equal to the number of C + H atoms in the alkene

Question 5

why is cracking important

Answer 5

• makes the best use of petroleum
• cracking always produces short- chain compounds with a Carbon- carbon double bond. This bond makes compounds reactive- makes plastics

Question 6

what is the general formula for alkanes

Answer 6

CnH2n+2

Question 7

what is the general formula for alkenes

Answer 7

CnH2n

Question 8

where is heat applied

Answer 8

at the aluminium oxide

Question 9

what is the test for alkenes

Answer 9

the gas produced was tested with bromine water. Brown to colourless

Question 10

describe the products of alkane

Answer 10

one of the products is always alkene

Question 11

give the homologous series

Answer 11

1. Alkanes - C + H atoms, single bonds
2. Alkenes - C + H plus 1 double Carbon bond
3. Alcohols - C + H plus at least 1 O-H
4. Carboxylic acids - H + C plus at least 1 COOH group

Question 12

state the substances present in the process of cracking

Answer 12

• 3-4cm depth of mineral wool soaked with a hydrocarbon oil
• aluminium oxide catalyst

Question 13

what is methyl

Answer 13

CH3

Question 14

general formula for alcohol

Answer 14

CnH2n+1OH

Question 15

general formula for carboxylic acids

Answer 15

CnH2n+1CO2H

Question 16

why must the delivery tube be lifted out of the water the moment heating is stopped

Answer 16

water will get sucked up into the hot test tube and it might crack

Question 17

what is cracking?

Answer 17

breaks molecules down into smaller ones

Question 18

give the cracking of ethane

Answer 18

ethane –> ethene + hydrogen

Question 19

what are alkanes

Answer 19

1. the simplest family of organic compounds
2. Hydrocarbons
3. carbon bonds are all single bonds
4. form a homologous series usually with the formula CnH2n+2
5. unreactive

Question 20

what are isomers

Answer 20

compounds with the same molecular formula but different structures

Question 21

give the equation for the incomplete combustion of methane

Answer 21

2CH4 + 3O2 –> 2CO + 4H2O

Question 22

what do alkanes also react with

Answer 22

chlorine in sunlight

Question 23

describe the trend of alkanes

Answer 23

first 4 alkanes are gases at room temperature. the next 12 are liquids and the rest are solids. Boiling points increase as attraction increases

Question 24

where are alkanes found

Answer 24

petroleum and natural gas

Question 25

what can alkanes act as

Answer 25

fuels

Question 26

give examples of alkanes

Answer 26

methane, ethane, propane, butane

Question 27

why do branched isomers have a lower boiling point

Answer 27

because the branches make it hard for the molecules to get close so the attraction between them is weak and less heat is needed to overcome it

Question 28

give the equation for the combustion of methane

Answer 28

CH4 + 2O2 --> CO2 + 2H2O + heat energy

Question 29

what are addition reactions

Answer 29

an addition reaction turns an unsaturated alkene into a saturated compound

Question 30

what are the bonds of the alkenes and why

Answer 30

- unsaturated - because they have double bonds

Question 31

how are alkenes made

Answer 31

from alkanes by cracking

Question 32

why are alkenes more reactive than alkanes

Answer 32

because the 2 bond can break, to add on other atoms

Question 33

what can you use to test whether a hydrocarbon is unsaturated

Answer 33

bromine water. orange- colourless

Question 34

use of paraffin

Answer 34

fuel for aircraft, oil stoves and lamps

Question 35

describe the list of refinement of crude oil from bottom to top

Answer 35

1. bitumen 2. lubricating fraction 3. fuel oil 4. diesel oil 5. paraffin 6. naphtha 7. gasoline (fuel) 8. refinery gas

Question 36

use of fuel oil

Answer 36

fuel for power stations, ships and for home heating systems

Question 37

what happens as you go down the tower

Answer 37

boiling point and viscosity increases

Question 38

how is natural gas formed

Answer 38

mainly methane gas and is usually found with petroleum

Question 39

what is the minimum and maximum temperatures

Answer 39

400 celcius - bottom 25 celcius- top

Question 40

use of naphtha

Answer 40

starting point of feedstock for many chemicals and plastics

Question 41

which substance is very thick and heavy liquid

Answer 41

lubricating fraction

Question 42

use of bitumen

Answer 42

road surfaces and roofs

Question 43

how is petroleum formed

Answer 43

formed from remains of dead organisms that fell to the ocean floor and high pressures slowly converted them into petroleum

Question 44

use of lubricating fraction

Answer 44

oil for engines and machinery, waxes and polishes

Question 45

use of refinery gas

Answer 45

bottle gases for cooking and heating

Question 46

what is an organic compound

Answer 46

contains carbon and usually hydrogen eg. petroleum

Question 47

how is coal formed

Answer 47

the remains of vegetation that grew in ancient swamps. Pressure and heat slowly converted it to coal, over millions of years

Question 48

use of gasoline

Answer 48

fuel for cars

Question 49

which substance is a solid

Answer 49

bitumen

Question 50

why is petroleum called a non-renewable source

Answer 50

because it will run out one day as we are using it up much faster that it can form

Question 50

biggest sources of fossil fuels

Answer 50

natural gas coal petroleum

Question 51

where does the refinement of crude oil happen and describe how

Answer 51

fractional distillation - carried out in a tower that is kept very hot at the base and cooler toward the top

Question 52

what is a hydrocarbon

Answer 52

contain ONLY carbon and hydrogen