Env. Sci ch. 15 Energy from Organic Fuels List all the forms of energy you can think of

15.1 The Need for Energy I. Law of Conservation of Energy A. Storage, Transfer, and conversion of Energy behind all life on Earth a. Fuel – any substance from which energy can be obtained. Electricity generated by the conversion of other forms of energy Not 100 % efficient

II. Changing Energy Needs A. Hunter Gatherer societies a. used little energy – light, heat and cooking B. Agricultural Revolution a. animals became energy sources C. Industrial Revolution a. machines, use large amounts of fuel

III. Fuels from Organisms Organic Fuels – contain C cpds that were once living organisms A. hydrocarbon – cpd made of only H and C -methane, CH4 -ethane C2H6 -octane C8H18 B. All hydrocarbons in a chain except methane -straight, branched or ring

C. May have diff configuration e.g. C8H 18 a. Straight chain octane b. Branched chain iso- octane c. Gasoline octane rating formula based on energy compared to energy of iso- octane

D. Addition of other chemicals to hydrocarbons -sulfur or lead -considered impurities -lead in gasoline improves useable energy --also incr. pollution

IV. Fossil Fuels Derived from the remains of organisms that lived long ago E.g. coal (solid), petroleum (liquid) and natural gas (gas)

15.2 Coal I. Formation of Coal took millions of years Many parts of Earth were covered with swamp Plants covered by layers of sediment Water forced out, became solid rock More carbon means more energy

A. Peat -A brittle brown plant material containing a great deal of water and a low percentage of carbon. -1 st stage in coal formation -resembles decaying wood -located near earths surface

B. Lignite Soft, brown coal composed of about 40% carbon 2 nd stage in coal Below earth’s surface must be mined

C. Bitminous Coal -a soft coal composed of up to 85% carbon Deep in earth’s crust Most abundant coal Used in industry Used in power plants

D. Antracite Coal A hard coal composed of up to 95% carbon Deep in ground, less abundant Most expensive Coal areas in the US

15.3 Petroleum and Natural Gas I. Petroleum – liquid fossil fuel I. Made from remains of sea organisms A. one of worlds most important resources -is separated into a variety of products a. gasoline b. jet fuel c. diesel fuel

d. fuel oil for heating e. grease and other lubricants -Non renewable takes millions of years to form Demand continues to increase

II. Natural Gas A. mixture of hydrocarbons Mostly methane B. Burns cleaner than coal or oil Energy efficient, cost less to use -does not have to be converted to electricity Often trapped above petroleum

16.4 Other Organic Fuels I. Alternative Fuels -fuels from other organic sources A. Problems with Fossil Fuels a. availability b. pollution

B. Biomass Fuels Formed from the products of living organisms Wood Garbage Methane Alcohol Are renewable, can be produced in large quantities

a. wood - developing nations use as their energy source - gives off smoke and CO2 -damaging to natural forests

b. Garbage About 2/3 of material in garbage can be burned Heat changes water into steam, steam generates electricity

C. Methane From decaying garbage in dumps Used the same way as natural gas

d. Alcohol Bioconversion – conversion of organic materials into fuels a hydrocarbon in which one H atom is replaced by a hydroxyl (OH) group Ethanol – made by yeast/fermentation -liquid biomass -burns cleanly -renewable