Presentation on theme: "Combustion Reactions. What is combustion? a very rapid reaction of a substance with oxygen to produce compounds called oxides. FUEL + OXYGEN OXIDE +"— Presentation transcript:
What is combustion? a very rapid reaction of a substance with oxygen to produce compounds called oxides. FUEL + OXYGEN OXIDE + ENERGY
commonly referred to as burning easily identified by the production of heat (exothermic) type of synthesis reaction
Requirements Three requirements for a combustion reaction
Fuels Gaseous Fuels Natural Gas/Methane - used for cooking, heating etc. Acetylene - used in welding, cutting etc. Liquid Fuels Petrol - used for internal combustion engines etc. Paraffin/kerosene - used in heating appliances etc Alcohols - used widely but includes preservatives, preparations, solvents etc. Oils - used for lubrication etc.
Fuels Solid Fuels Wood/paper/card. Plastics - most plastics will release toxic smoke during combustion. Metals - some metals are flammable, although usually very high temperatures are required. Foodstuffs - we actually 'burn' our food in order to cook it. The most common fuels are hydrocarbons
Complete Combustion Complete combustion of a hydrocarbon produces carbon dioxide gas and water vapour. Hydrocarbon + Oxygen Carbon dioxide + Water methane + oxygen carbon dioxide + water CH O 2 CO H 2 O
Complete Combustion Complete combustions occurs when: Sufficient oxygen is present Temperature is hot enough Complete combustion is characterized by a blue flame. The flame is hotter than the flame of incomplete combustion.
Incomplete Combustion If insufficient oxygen is present, hydrocarbons burn to produce water vapour along with carbon monoxide, carbon dioxide and/or solid carbon. 2CH O 2 2CO + 4 H 2 O CH 4 + O 2 C + 2 H 2 O
Incomplete Combustion Incomplete combustion is characterized by an orange or “dirty” flame. Produces black “soot” and the poisonous gas carbon monoxide
Time to Get to Work combustion animation Page 140 #19-24 Page 141 #41, 43, 46, 47, 49