Transcript Document
Fossil Fuels Chapter 11.2 Fossil Fuels 1. Fossil Fuels a.Fuel formed from the remains of living organisms, such as coal, petroleum, and natural gas. b.Fossil fuels consist primarily of compounds called hydrocarbons. Fossil Fuels Hydrocarbons i. Hydrocarbons are compounds made up of atoms of carbon and hydrogen. 1.These compounds contain energy originally obtained from sunlight by plants and animals that lived millions of years ago. 2.When hydrocarbons are burned, energy is released as heat and light that we can use. Hydrocarbons Coal Formation 2. Formation of Coal a. Coal is a dark colored, organic rock formed from chemical and physical changes of plant material over millions of years. b. Carbonization is the process by which partially decomposed trees and other plants are buried in swamp mud and transformed into carbon. i. The process of carbonization occurs when bacteria consume the plant material and release methane and carbon dioxide gas. When these gases escape the swamp, only the carbon is left. Types of Coal 3. Types of Coal a. Peat is the partial decomposition of brownish–black plant remains. Peat is the substance that all coal is formed from. b. The three main types of coal are lignite, bituminous, and anthracite. Peat Lignite i. Lignite is the first type of coal formed from the peat. As layers of sediment cover the peat depleting the oxygen so decomposition can’t continue, they cause pressure, which squeeze out the water and gas, which then becomes a denser, brown lignite. Lignite Bituminous Coal 1.Subbituminous coal, also called black lignite, is generally dark brown to black coal, and falls between lignite and bituminous coal. ii. The added pressure of more deposited sediments further compresses the lignite to form bituminous coal, or soft coal. 1.Bituminous coal is the most abundant type of coal. Subbituminous & Bituminous Anthracite iii. Where the folding of the earth’s crust produces extremely high temperatures and pressure, bituminous coal is changed into anthracite, the hardest of all coal. iv.Bituminous coal and anthracite consists of 80% to 90% carbon, which makes them a great energy resource. Anthracite Petroleum & Natural Gas 4. Petroleum and Natural Gas a. Petroleum and natural gas are mixtures of hydrocarbons. i. Petroleum oil consists of liquid hydrocarbons. ii. Natural gas consists of gaseous hydrocarbons. Formation of Petroleum & Gas b. Formation of petroleum and Natural Gas i. When microorganisms died in shallow prehistoric oceans and lakes, their remains accumulated on the ocean floor and lake bottoms which were then covered and buried by sediment. Formation of Petroleum & Gas ii. As the amount of sediments increased, so did the heat and pressure on the microorganisms. This added heat and pressure was enough to cause a chemical change to form petroleum and natural gas. Deposits of Petroleum & Gas 5. Petroleum and Natural Gas Deposits a. Sedimentary rock has many interconnected spaces between the rock particles. This allows liquids and gases to flow freely through the rock. Deposits of Petroleum & Gas b. As sedimentary rock becomes deeply buried under overlying sediments, pressure increases. This increasing pressure causes the water and hydrocarbons out of the rock and up through the layers of permeable rock until they come to a layer of impermeable rock. i. This impermeable layer of rock is called cap rock. Deposits of Petroleum & Gas c. The water, oil, and natural gas separate under the cap rock due to their densities. Natural gas is less dense, then oil, then water. d. Rock that liquids can easily flow through is called permeable rock. e. Rock that liquids cannot easily flow through is called impermeable rock. Deposits of Petroleum & Gas f. Crude oil is unrefined oil and has many uses. Petrochemicals are chemicals derived from petroleum and are the main component in over 3,000 products. i. These products include plastics, synthetic fabrics, medicines, tars, waxes, synthetic rubber, insecticides, chemical fertilizers, detergents, and shampoos. Fossil Fuel Supplies 6. Fossil Fuel Supplies a. Fossil fuels are a nonrenewable resource. b. Coal is the most abundant fossil fuel in the word, occurring on every continent. i. While coal is very abundant, scientists predict that world wide coal reserves will only last another 200 years. ii. However, two-thirds of it are deposited in three countries: the US, Russia, and China. Fossil Fuel Supplies c. Scientists estimate that 75% of all the petroleum in the US has already been discovered, however, much of the undiscovered supply is thought to be under the ocean floor along the edges of North America. Fossil Fuels & the Environment 7. Fossil Fuels and the Environment a. The use of any fossil fuels has an impact on the environment. i. Strip mining 1. Strip mining coal leaves deep ditches where coal is removed 2. Rocks and topsoil that are displaced to expose the coal are left in steep slopes, and without plants and topsoil to protect it, the exposed land will weather away. Fossil Fuels & the Environment 3. Wet rocks that are exposed during mining can give off acids. a.These acids can be carried to nearby rivers and streams causing harm to aquatic life. 4.Since strip mining can be so damaging to the environment, the US government has place many regulations to decrease and/or prevent the damaging of our environment. Air Pollution ii. Air Pollution 1.The burning of any fossil fuel causes pollution in the air. While some fuels may be less damaging such as natural gas, they do still pollute the environment. a.Much of this air pollution can contribute to acid rain Spills iii. Spills 1. Fossil fuel spills happen rarely, but have a huge and sudden impact on the environment when they do. a.Examples include spills from wells, tankers, and pipelines.