Alkanes Flashcards
(12 cards)
Physical properties of alkanes
Non polar
As Mr increases boiling points increases
Branched chains have lower melting points
Insoluble in water
Seperated by fractional distillation
Fractional distillation
Continual evaporation and condensation of mixture separating by boiling points
What is a fraction
Groupnof compounds with similar boiling points
Thermal cracking
High temperatures 1000-1200K
Extreme high pressure 70atm
Short time
Shorter chain alkane and alkene
Catalytic cracking
Zeolite catalyst
High temperatures 800-1000K
Low pressure 1-2atm
Branched alkanes cycloalkanes aromatic compounds
Side effects of internal combustion engine
High temperatures and pressure causes nitrogen and oxygen from the air to react
Forms harmful nitrogen oxides
Also causes sulfur to react with oxyg3n to form acidic sulfur dioxide
Side effects of products from internal combustion
CO2- global warming
CO- toxic gas
C- asthma
NOx- photochemical smog
SO2- acid rain
Hydrocarbon- react with NOx to formnground level ozone
Global warming
Infrared radiation from sun travels back through earth’s atmosphere prevented from escape by gases
Greenhouse effect
Water vapour, carbon dioxide, methane
Acid rain
SO2 and NOx react with water in airways to produce acid
SO2 + H2O + 0.5O2 -> H2SO4
Destroys trees and vegetation
Corrodes buildings
Kills fish
Photochemical smog
Pungent toxic gasesand solid particles close to surface
Irritates eyes
Nasal congestion
Severe lung disease
Catalytic converters
Reduces amount of pollutants, converts to less toxic gases
Platinum and rhodium catalysts
2NO + 2CO -> 2CO2 + N2
C8H18 + 25NO -> 8CO2 + 12.5N2 +9H2O
Removal of sulfur dioxide
CaO +SO2 -> CaSO3
Or
CaCO3 + SO2 -> CaSO3 + CO2
Flue gas desulfurisation
CaSO3 oxidised to CaSO4 which is useful construction material
