Interactive Chemistry Worksheets for Students
Combustion is the burning of a fuel with the production of energy or heat
Cellular respiration is the process whereby cells in our bodies obtain energy. Glucose reacts with oxygen producing carbon dioxide and water with the release of energy.
Glucose + oxygen carbon dioxide + water + energy
C6H12O6 + 6O2 6CO2 + 6H2O + energy
Fossil fuels are made up of hydrocarbons. Hydrocarbons are compounds that contain the elements hydrogen and carbon. Examples are methane, CH4, propane, C3H8, butane, C4H10 and octane, C8H18
Hydrocarbons readily burn or undergo combustion reactions. Combustion may be complete or incomplete.
Complete combustion of fossil fuels results the production carbon dioxide and water. The incomplete combustion of fossil fuels results in the formation of carbon monoxide and soot (carbon).
Methane + oxygen carbon dioxide and water
CH4 + 2O2 CO2 + 2H2O
Methane + oxygen carbon monoxide and water
CH4 + 1.5O2 CO + 2H2O
Methane + oxygen carbon and water
CH4 + O2 C + 2H2O
As the amount of oxygen is decreased from a ratio of 2 to 1.5 to 1 in the above three equations, the combustion products change from carbon dioxide to carbon monoxide to carbon or soot. As the soot is heated in the flame it produces a yellow flame. In real life there is a mixture of carbon monoxide and soot from the incomplete combustion of hydrocarbons as well as unburnt hydrocarbons.