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Carbon Chemistry. What’s so special about Carbon?. Fourth most abundant element in the universe. Essential to life on earth. . Many different forms… carbon dioxide (CO 2 ), limestone (CaCO 3 ), wood, plastic, diamonds, and graphite. Carbon – The Element of Life.
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What’s so special about Carbon? • Fourth most abundant element in the universe. • Essential to life on earth. • Many different forms… carbon dioxide (CO2), limestone (CaCO3), wood, plastic, diamonds, and graphite.
Carbon – The Element of Life • Unique atomic structure… form covalent bonds with up to four other atoms. • Elements with either less or more than 4 valence electrons can only form a maximum of 3 covalent bonds, this is why 4 is a magic number and why carbon is special. • Lightest element (and therefore the smallest) with four valence electrons
Carbon Structures Chains Rings Branches
Carbon Bonds Single Double Tripple
Inorganic Compounds Inorganiccompounds are those compounds that were never part of a living organism Examples: Carbon dioxide and Carbon monoxide The line between inorganic and organic carbon compounds is becoming less and less important to scientists as many non-living compounds are derived from once living organisms.
Organic Compounds Organic compounds are those compounds found in any organism that is living or was once living. Chemically… Organic compound – any compound that contains the elements carbon and hydrogen. They include carbohydrates such as glucose, fructose, and sucrose And hydrocarbons such as methane and hexane
Carbohydrates • Monosaccharides- One unit (Simple Sugar) • Disaccharides- Two units (Simple Sugar) Glucose- stored in our body Fructose- sugar in fruit Sucrose- one glucose + one fructose = table sugar
Carbohydrates • Polysaccharides- Many units (Complex Carbs) Starch- a long chain of glucose- found in plants Similarly, Glycogen is glucose stored in animals and humans. Cellulose is glucose chains linked together and forms strong plant fibers.
Hydrocarbons • Pure hydrocarbons- only Carbon + Hydrogen Isomers of Octane- often added to gasoline to stop the “knock” in the engine
Properties of Hydrocarbons Hydrocarbons are the simplest organic compounds, made up of only two elements -- they have low melting and boiling points -- hydrocarbons are flammable and tend to burn in combustion reactions -- hydrocarbons mix poorly with water (they are nonpolar) -- hydrocarbons are used for many of our fuels such as heating oil, diesel fuel, gasoline, coal and methane.
Combustion is a chemical process in which a substance reacts rapidly with oxygen and gives off heat. The original substance is called the fuel, and the source of oxygen is called the oxidizer. The fuel can be a solid, liquid, or gas, although for airplane propulsion the fuel is usually a liquid. The oxidizer, likewise, could be a solid, liquid, or gas, but is usually a gas (air) for airplanes.
To summarize, for combustion to occur three things must be present: a fuel to be burned, a source of oxygen, and a source of heat. As a result of combustion, exhausts are created and heat is released. You can control or stop the combustion process by controlling the amount of the fuel available, the amount of oxygen available, or the source of heat.
Combustion • Rapid chemical combination of a substance with oxygen, producing heat and light. • Burning • Exothermic chemical reaction. • Creates heat (lightglowing/flame) • Fuels = organic compounds (especially hydrocarbons) in the gas, liquid or solid phase.