3. AlkanesThe general formula
for an alkane is
CnH2n+2
All possible
bonds are
used
‘Saturated’ hydrocarbons are compounds which contain only carbon and hydrogen bonded
exclusively with single bonds.
4. Combustion of Alkanes
Burning alkanes in plenty of oxygen allows for
complete combustion
• alkane + oxygen carbon dioxide + water
Complete
Combustion
Combustion Equation
E.G: CH4(g) + 2O2(g) CO2(g) + 2H2O(g)
Carbon Dioxide is a Greenhouse gas. This contributes to
Global Warming
5. Incomplete
CombustionBurning alkanes in a limited supply of oxygen
leads to incomplete combustion
• alkane + oxygen carbon monoxide + water
Incomplete combustion Equation
E.G: CH4(g) + 3/4 O2(g) CO(g) + 2H2O(g)
Carbon Monoxide is a Poisonous gas.
Depending on the
alkane burnt ,carbon (s)
can also be produced.
Carbon (soot)
contributes to global
dimming
+
6. NOx & Unburned
Hydrocarbons
NOx =General formula for Nitrogen oxides
• Toxic & Poisonous
High temperatures and pressures in a car
engine cause nitrogen and oxygen in the air to
react
E.G: N2g) +O2(g) →2NO(g)
Nitrogen oxide can further react to produce nitrogen dioxide:
2NO(g) +O2(g) →2NO2(g)
pollution from burning fuels
Leads
to ACID
RAIN
7. Unburned Hydrocarbons
Engines don’t burn all of the fuel molecules
Unburnt Hydrocarbons
irritates
people’s eyes
aggravates
respiration
problems
lung problems
Smog
8. Catalytic
ConvertersRemoves pollutants from the exhaust gases by
converting more than 90% of the pollutants into
less harmful gases.
E.G: 2NO (g) N2 (g) + O2 (g)
CO (g) + 1/2O2 CO2 (g)
C9H20 (g) + 14O2 9CO2 + 10H2O (g)
Catalytic Convertors
•Large Surface Areas
•Transition metals
