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Chapter 7-Resources and Energy Section 1 – Mineral Resources Section 2 – Nonrenewable Energy Section 3 – Renewable Energy Section 4 – Resources and Conservation Section 1 – Mineral Resources More than 3,000 different minerals have been identified in the Earth’s crust. • Minerals can be metals (like gold) or nonmetals (like sulfur) – Metals can be identified by shiny surfaces and are good conductors of heat and electricity. – Nonmetals have a dull surface and are poor conductors of heat and electricity. • Native elements can exist in the earth’s crust as nuggets of pure metal – gold, silver, and copper. • Most other minerals are compounds of two or more minerals. • Ore is a mineral deposit from which metals and nonmetals can be removed profitably. • Ores are formed in a variety of ways • Formed by cooling magma – as the magma cools, dense metallic minerals sink and form layers at the bottom of the magma chamber. • Formed by contact metamorphism – Contact metamorphism is a process that occurs when magma comes into contact with existing rock. Heat and chemical reactions with hot fluid from the magma can change the composition of the surrounding rock, forming ores. When many thick mineral veins form in a relatively small region, the ore deposit is called a lode. • Formed by moving water – water breaks down the rock into fragments that are carried in the stream until the current is too weak to carry the dense metals. The fragments drop to the bottom of the stream beds forming placer deposits. • Uses of Mineral Resources – Some metals are prized for their beauty and rarity like gold, platinum, and silver. Rare nonmetallic minerals are called gemstones and display extraordinary brilliance and color when they are specially cut for jewelry. Some minerals are used for building materials. • Mineral Exploration and Mining – companies are often looking for new areas to mine. Areas are tested before mining to make sure they will be profitable. – Subsurface mining – miners work underground to recover mineral deposits. – Surface mining – miners strip the metals from the surface – Placer mining – mined by dredging rivers and streams – Undersea mining – trying to find ways to mine undersea Section 2 – Nonrenewable Energy • Many of the Earth’s resources are used to generate energy. Energy resources that exist in limited amounts and cannot be replaced quickly are called nonrenewable resources. • Fossil fuels are nonrenewable resources formed from the remains of living things. Examples are coal, petroleum, and natural gas. • The most commonly burned fuel is coal. Coal is formed when dead plant material is buried in swamp mud and becomes peat. Bacteria consumes the peat and uses up all the oxygen. Coal can only be formed where there is no oxygen. • Two types of coal – Pressure and the weight of sediment causes the peat to be compressed and it forms the coal called bituminous coal. This is the most abundant type of coal. It is made of 80% carbon. – Under continued heat and pressure, bituminous coal is changed to anthracite, the hardest form of coal. Anthracite is made of 90% carbon. • Both types release a large amount of heat when they burn. • Petroleum and natural gas are formed when microorganisms and plants died in shallow oceans or lakes. They become covered in sediment. As more sediment covers it, heat and pressure increases and converts the material into petroleum and natural gas. • Petroleum and natural gas are most commonly found in permeable sedimentary rock. The liquid rises up through the rock filling the spaces to form the oil resevoir. • Natural gas, petroleum and water are found in layers in this order. • Crude oil or unrefined petroleum are used in the production of plastics, synthetic fabrics, waxes, shampoo, medicines, insecticides, and fertilizers. Nuclear Energy • Nuclear energy is energy produced by bombarding atoms and releasing the energy that holds the atom together. • The splitting of a large, heavy atom into two or more smaller nuclei is called nuclear fission. • The energy needed to hold an atom together is more than 1 million times stronger than the strongest chemical bonds between atoms. • Nuclear energy is based on a chain reaction. The first