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Mr. Chapman Science 10. Combustion Reactions. What is a combustion reaction?. A combustion reaction occurs when a hydrocarbon reacts with oxygen gas. A hydrocarbon is any chemical that has the chemical formula C x H y . For example, the following are ALL hydrocarbons:
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Mr. Chapman Science 10 Combustion Reactions
What is a combustion reaction? • A combustion reaction occurs when a hydrocarbon reacts with oxygen gas. • A hydrocarbon is any chemical that has the chemical formula CxHy. For example, the following are ALL hydrocarbons: • Methane (CH4), Butane (C2H6), Octane (C3H8), as well as gasoline and others.
5. Combustion Reactions • Combustion reactions occur when a hydrocarbon reacts with oxygen gas. • This is also called burning!!! In order to burn something you need the 3 things in the “fire triangle”:1) A Fuel (hydrocarbon)2) Oxygen to burn it with3) Something to ignite the reaction (spark)
Combustion Reactions • In general: CxHy+ O2 CO2 + H2O • Products in combustion are ALWAYS carbon dioxide and water. (although incomplete burning does cause some by-products like carbon monoxide) • Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C8H18)
Combustion Reactions Edgar Allen Poe’s drooping eyes and mouth are potential signs of CO poisoning.
Examples – Combustion Reactions • Write the products for each of the following chemical reactions, and then balance the equations: • C3H8 + O2 • CH4 + O2 • C5H12+ O2 • C4H10+ O2
Fossil Fuels • Hydrocarbons are a type of fossil fuel. You may have heard that burning of fossil fuels may not be good for the environment. • You also may have heard that fossil fuels are a non-renewable resource. This is due to the fact that they are created over millions of years from compressed remains of organisms.
Dangerous By-Products: • When hydrocarbons and other fossil fuels burn, they generally leave dangerous by-products in the air. • One of the main by-products is carbon dioxide, which is also known as a greenhouse gas. Many people believe this is causing global warming, but there is now reason to doubt that. • The following is a list of other dangerous by-products that can happen running a vehicle:
http://www.hybridcars.com/oil-environment • Carbon dioxide is the dominant greenhouse gas that causes global warming. • Carbon monoxide, when inhaled, impairs the flow of oxygen to your brain. • Sulphur oxides contribute to respiratory illness, and aggravate existing heart and lung diseases. • Oxides of nitrogen (NOx) react with compounds in the air to cause acid rain and ozone (the main reason for smog). • Particulate matter are an established cause of lung problems, including cancer. • Hydrocarbons, in their many forms, irritate the lung and other tissues, contribute to birth defects and cause other illnesses including cancer. • Lead damages organs, affects the brains, nerves, heart, and blood.