Objectives

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Objectives

1. Describe the chemicals in the Earths atmosphere,
   hydrosphere and lithosphere.
2. Describe and recognize factors that determine the
   feasibility of mining.
3. Define oxidation and reduction.
4. Identify oxidation and reduction processes.

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2.B.1 Sources and Uses of Metals

1. Human needs for resources must be met by chemical
   supplies currently present on Earth.
2. The needs include creating a new coin,
   manufacturing of clothing, petroleum products,
   fertilizer for food and energy needs.
3. Resources can be cataloged by where they are
   found on Earth.

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2.B Earths Mineral Resources
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Earths Resources

• Atmosphere provides nitrogen, oxygen, neon and
  argon.
• Hydrosphere water and dissolved minerals.
• Lithosphere solid part of the earth which
  provides the greatest variety of chemical
  resources. These include petroleum, metals, ores
  and minerals.

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Earths Resources

• Ore a naturally occurring rock or mineral that
  can be mined.
• An ore contains a mixture of components.
• Of these minerals are the most important part of
  the ore.

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Lithosphere
Average thickness is 3,840 miles. Most of the
mined resources occur in the first 25 miles
(crust). Metals found in the crust include
aluminum, sodium, iron, calcium, magnesium and
potassium. These metals must be mined form the
earth.
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2.B Earths Mineral Resources

• Use Table 2.3 (pg. 136) to answer these
• 1. What metal might Australia wish to obtain from
  the US?
• 2. What metal could Australia trade to the US to
  obtain the metal in the previous question?
• 3. From which nation would you expect the US to
  obtain nickel? Why?
• 4. Give examples of two trade agreements by which
  China could obtain iron ore in exchange for a
  metal it has in abundance.
• 5. What metals might Canada seek to obtain
  through trade?

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Challenges faced in mining

1. Use of supplies
2. Where should mining occur
3. The quantity of useful ore found at the site
4. The percent of metal in the ore
5. The type of mining and processing needed to
   extract the metal from its ore
6. The distance between the mine and metal-refining
   facilities and markets
7. The metals supply vs. demand status
8. The environmental impact of the mining and metal
   processing.
9. Can you think of any others?

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Mining Copper Ores
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Mining Copper Ores

• The first copper ores mined were relatively rich
  in copper metal 35 to 88.
• Such ores are no longer available.
• Today it is possible to mine ores containing less
  than 1 copper
• These ores are chemically processed to produce
  metallic copper.

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Properties of Copper
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Mining Copper Ores

• Copper is one of the most familiar and widely
  used metals in society. Uses include
• Electrical wiring.
• Second only to silver in electrical conductivity.
• Relatively low cost and corrosion resistance
• Ductility ability to be drawn into wires.
• Used to produce brass, bronze, jewelry and
  artwork.

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Mining Copper Ores

• Will future developments increase or decrease the
  need for copper?
• What copper substitutes are available?

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B.2 Production vs. Use

• Follow the guidelines on page 138-139 to research
  the metal you are assigned.
• Prepare a PowerPoint presentation answering
  questions (following slide) about your metal.
• Due Class Presentation DATE

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PowerPoint Presentation

• Cover slide name of metal / name of student
• Symbol of metal, number of protons, common
  isotopes of the metal
• Where is metal found on earth (countries)
• History of metal
• How abundant is metal (worldwide production)
• The metals properties (shiny, color soft, etc.)
• Three current uses of metal

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B.3 Converting Copper
Lab Handout and page 139 in textbook
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Some useful websites for your research

• All metals http//minerals.usgs.gov/minerals
• http//pearl1.lanl.gov/periodic/default.htm
• Aluminum www.aluminum.org
• Copper www.copper.org
• Lead www.ldaint.org/default.htm
• Nickel www.nickelinstitute.org
• Silver http//www.silverinstitute.org/index.php
• Tin http//minerals.usgs.gov/
• Zinc www.zincworld.org

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B.4 Metal Reactivity

• 2 Cu(s) O2(g) ? 2 CuO (s)
• Identify the reactant(s).
• Identify the product(s).
• What do the letters in parentheses represent?

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Symbols used in chemical equations

• (s) solid / precipitate
• (l) liquid, typically H2O, Hg and Br
• (g) gas
• (aq) aqueous solutions, the solvent has to be
  water. Ex. Salt water solution

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Activity Series

• The ranking of elements according to their
  chemical reactivity.
• For example, Au (gold), does not react with any
  components of air such as oxygen. This is one
  reason why it is used in jewelry. Therefore it is
  ranked low on the Metal Activity Series
• Au, also used for gold plating electrical
  contacts used in air bags. They are dependable
  because oxides do not form on gold-plated
  surfaces.

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Metal Activity Series

• Reactive metals are more difficult to release
  from their compounds.
• Ex.
• Can zinc (Zn) replace Magnesium in Mg(NO3)2?
• Can Zn ever replace copper (Cu) in a chemical
  reaction?

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• Please rank the following elements in order of
  reactivity (based on the activity series chart on
  page 145). List the most reactive element first.
• Gold, copper, chromium, magnesium, potassium

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B.5 Relative Reactivities of Metals
Lab Handout and page 142 in textbook
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B.6 Metals

• Certain metals in nature are found in the
  uncombined stated.
• These metals are known as free elements, rather
  than in combination with other elements.
• These metals include gold, copper and silver.
• Because they are not combined with other elements
  they were the first metals used by man.
• These metals are also very unreactive.

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• Most metals are usually found in the form of a
  metallic ore (combined with other elements)
• Metallic ores are also known as minerals.
• These metals include aluminum and iron.
• These metals need to be extracted or separated
  from their ores to yield the pure metal.
• Bronze and brass are a combination of copper with
  another metal and not a pure metal.
• Because these metals need to be extracted from
  their ores they were used by humans at a later
  time.

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Metal alloys

• An alloy is a mixture of 2 or more elements (one
  must be a metal)
• These are uniform throughout, so a homogeneous
  mixture
• Examples Brass (copper and zinc) Sterling
  silver (silver and copper) Bronze (copper and tin)

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Why have alloys?

• Alloys are important because they are combining
  properties and are often superior compared to the
  pure elements
• Typically, more inexpensive than the pure
  element
• Sterling silver vs pure silver

0.95 vs 1.68
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Why have alloys?

• Alloys are important because they are combining
  properties and are often superior compared to the
  pure elements
• Typically, more inexpensive than the pure
  element
• Sterling silver vs pure silver

0.95 vs 1.68
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B.8 Oxidation Reduction Reactions

• B.8 Reading Guide Worksheet

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IONS Atoms are neutral because the protons
which are positive and electrons that are
negative balance out the charge, so there are the
same numbers of protons and electrons in an
atom. An ion is an atom or group of atoms that
has a positive or negative charge due to loss or
gain of electrons. There are two forms of ions
cation and anion.
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B.8 Review of Ions

• Cation positive ion
• Anion negative ion
• Monoatomic ions (1 atom)
• Polyatomic ions
• (group of atoms)

Cu2 (loss of electrons)
Cl- (gain of electrons)

• Na, Cl-, Mg2, O2-, Al3, N3-
• NH4, CO32-, SO42-, PO43-

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B.8 Review of Ions
Cu ? Cu2 2e- 29
protons () 29 protons () 29 electrons (-) 27
electrons (-) Net charge 0 Net charge
2 Net charge -2
Overall charge on both sides of the reaction
arrow are the same
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B.8Oxidation Reduction Reaction

• Converting copper cation (2) to copper metal
• requires the addition of 2 electrons

• Reduction
• Gain of electrons by a reactant.
• Ex.
• Cu2 2e- ? Cu
• The copper cation was reduced, lost its charge by
  gaining electrons

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Mining and Refining

• Oxidation
• Loss of electrons there are electrons in the
  products
• Ex.
• Fe ? Fe3 3e-
• Iron is oxidized to an iron (III) ion by losing
  3 electrons

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Remember

• OIL RIG
• OIL Oxidation Is Loss (of electrons)
• RIG Reduction Is Gain (of electrons)

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Oxidation Reduction Reaction

• Oxidation and reduction reactions occur together
  and are called redox reactions.
• Cu2(aq) Mg(s) ? Cu(s) Mg2(aq)
• - Which reactant (Cu2or Mg(s)) is reduced?
• - Which is oxidized?

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Oxidation Reduction Reaction

• In a redox reactions the electrical charge, as
  well as, the atoms must be balanced on either
  side of the reaction arrow.
• This is known as a balanced equation.
• Cu2(aq) Mg(s) ? Cu(s) Mg2(aq)
• The total electrical charge on both sides of the
  reaction arrow is 2 in the above equation.
• On the activity series chart, magnesium is above
  copper allowing the reaction to occur.

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Oxidation Reduction Reaction

• Classwork Redox Worksheet (B8)

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Using Redox Reactions to obtain Pure Metals

• Techniques that are used to reduce metal cations
  to pure metals in industry include
• Electrometallurgy - use of electric current
• Pyrometallurgy use of heat
• Hydrometallurgy use of water

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Electrometallurgy

• This technique involves using an electrical
  current to supply electrons to the metal ions.
• This process is used when no other chemical
  reducing agent is available.
• Also allows for the production of very
  high-purity metals.

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Pyrometallurgy

• The use of heat (blast furnace) is used.
• Carbon or carbon monoxide are the common reducing
  agents supplying the electrons for the reduction
  reaction.
• The oldest method to obtain pure metals from ores.

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Hydrometallurgy

• This technique uses water to treat the ores.
• Used to recover gold and silver from old mines.
• Process is known as leaching.

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Oxidation Reduction Reaction

• Homework reading guide
• Due Use as a section review

• Homework B8 Supplement Worksheet
• Due