C12-alkanes

Question 1

what is a hydrocarbon

Answer 1

compound containing only hydrogens and carbons

Question 2

what is a saturated hydrocarbon

Answer 2

only contains single bonds between carbon atoms

Question 3

what is the general formula for an alkane

Answer 3

Cn+H2n+2

Question 4

name the first 4 alkanes

Answer 4

methane
ethane
propane
butane

Question 5

what si the trend in boiling points in alkanes

Answer 5

as chain length increases the boiling point increases

Question 6

why are hydrocarbons non polar

Answer 6

the electronegativity difference between carbon and hydrogen is very small

Question 7

what tyoe of IMF exists between hydrocarbon chains

Answer 7

van der waals

Question 8

why do branched chains have lower melting points

Answer 8

smaller surface areaso fewer VDW attractions

Question 9

how are mixtures of hydrocarbon seperated

Answer 9

feactional distillation

Question 10

what dies the word immisible mean

Answer 10

does not mix

Question 11

what is crude oil

Answer 11

a mixture of different hydrocarbons

Question 12

what is a fraction?

Answer 12

a group of compounds woth similar boiling points that are removed at the same lvl of the fractionatijg column

Question 13

where are smaller hydrocarbons collected

Answer 13

near the too of the fractionating column

Question 14

why do small chains have lower boiling points

Answer 14

less atoms in the chain so less VDW forces between then

Question 15

what happens in cracking?

Answer 15

long hydrocarbons are converted into smaller hydrocarbons

Question 16

why is cracking useful

Answer 16

shorter hydrocarbons are more useful

Question 17

name two tyoes of cracking

Answer 17

thermal and catalytic cracking

Question 18

gove the conditions for thermal cracking

Answer 18

1000-1200 K and upto 70 atm

Question 19

what is the time frame for thermal cracking

Answer 19

1s

Question 20

why is thermal cracking so short

Answer 20

to orevent complete decomposition of the hydrocarbon

Question 21

what catalyst is used in catalytic cracking

Answer 21

a zeolite

Question 22

what is a zeolite

Answer 22

an acidic mineral with a honeycomb structure made from aluminium oxide and silicon dioxide

Question 23

what are the conditions for catalytic cracking

Answer 23

800-1000 K 1-2 atm zeolite catalyst

Question 24

what is the purpose of the honeycomb structure

Answer 24

to increase surface area and so rate if reaction

Question 25

whats the time frame for catalytic cracking

Answer 25

2-4s

Question 26

what is produced in thermal cracking

Answer 26

high percentage of alkenes and some shirt alkanes

Question 27

what is peoduced in catalytic cracking

Answer 27

mainly aromatic hydrocarbons and motor fuels

Question 28

what is required for complete combustion

Answer 28

excess amount of oxygen

Question 29

what is a major component of natural gas

Answer 29

methane

Question 30

what is the major component of liquid petroleum gas

Answer 30

butane

Question 31

what is formed in incomplete combustion

Answer 31

carbon monoxide and water

Question 32

give three properties of carbon monoxide

Answer 32

toxic colourless odourless

Question 33

why is carbon minoxide toxic

Answer 33

binds to heamoglobin in red blood cells preventing them from carrying oxygen

Question 34

what is soot

Answer 34

carbon particulates

Question 35

what are the four stages of internal combustion engine

Answer 35

intake compression combustion exhaust

Question 36

how is the fuel ignited in an internal combustion engine

Answer 36

extreme temperature spark

Question 37

what tyoe of pollution is caused by CO

Answer 37

toxic gas

Question 38

what pollution is caused by C

Answer 38

particles exacerbate asmaa

Question 39

what pollution is caused by SO2

Answer 39

acid rain

Question 40

what pollution is caused by NOx

Answer 40

acid rain and photochemical smog

Question 41

what pollution is caused by hydrocarbons

Answer 41

react woth NOx to form geound lvl ozone which leads to resporatory problems

Question 42

why is greenhouse effect so important

Answer 42

wothout it, earth would be too cold to support life

Question 43

how is the CO2 in the atmosphere produced

Answer 43

respiration and combustion

Question 44

gow is the methane in the atmosphere produced

Answer 44

byproduct of sheep and cattle farming

Question 45

ph of normal rainy water

Answer 45

5.5

Question 46

why is rain water a weak acid

Answer 46

CO2 present in the atmosphere

Question 47

what pH is acid rain

Answer 47

lower than 5.5

Question 48

what problems does acod rain have

Answer 48

destroys trees and vegetation corrodes buildings and kills fishes in lakes

Question 49

what causes photochemical smog

Answer 49

toxic gases and minute solid oarticles suspended in air

Question 50

when is smog formed

Answer 50

when NOx, SO2 or unburnt hydrocarbons react with sunlight

Question 51

what health problems are associated with smog

Answer 51

irritated eyes nasal congestion emphysema

Question 52

what is the purpose of a catalytic converter

Answer 52

converts toxic compounds from the internal conbustion engine into kess harmful products

Question 53

what is a catalytic converter made of

Answer 53

a cermaic honeycomb covered in a thin layer of platinum and rhodium

Question 54

what is the process used to remove sulfur compounds from combustion emmisions called

Answer 54

flue gas desulfurisation

Question 55

what happens in flue gas desulfurisation

Answer 55

gasses are passed theough a wet slurry of CaO or CaCO3

Question 56

what do the CaO or CaCO3 do in flue gas desulfurisation

Answer 56

neutralise the acidic SO2

Question 57

1) what is the products of flue gas desulfurisation 2) what are they converted into

Answer 57

1) calcium (IV) sulfate (calcium sulphite) 2) calcium (VI) sulfate

Question 58

what is calcium (VI) suldate used for

Answer 58

construction

Question 59

what does [0] represent

Answer 59

oxygen from an oxidising agent