Key Concepts in Chemical Reactions and Metal Extraction

Key Definitions

  • Mass is conserved: In chemical reactions, the total mass of reactants equals the total mass of products; the number of atoms remains constant.
  • Energy is conserved: The total amount of energy remains unchanged in a chemical reaction, whether it is exothermic or endothermic.

Combustion of Methane

  • Chemical Reaction: Methane reacts with oxygen to produce carbon dioxide and water.
  • Symbol Equation: ext{CH}4 + 2 ext{O}2
    ightarrow ext{CO}2 + 2 ext{H}2 ext{O}
  • Balancing Numbers: Indicate the number of molecules involved in the reaction.

Writing Symbol Equations

Steps to Write Balanced Symbol Equations:

  1. Write the word equation with chemical formulas.
  2. Balance the equation by adding balancing numbers where necessary.
  3. Add state symbols:
    • (s) for solid
    • (l) for liquid
    • (g) for gas
    • (aq) for aqueous (dissolved in water)

Example: Magnesium and Oxygen

  • Word Equation: Magnesium + Oxygen → Magnesium Oxide
  • Balanced Symbol Equation: 2 ext{Mg} + ext{O}_2
    ightarrow 2 ext{MgO}

Metal Displacement Reactions

  • A more reactive metal displaces a less reactive metal from its compound.
  • Example: In the thermite reaction, aluminum displaces iron from iron oxide.
  • Key Concept: The reactivity series determines whether a displacement reaction occurs.

Extracting Metals

  • Ore: A rock that contains metal compounds from which the metal can be extracted.
  • Extraction Methods:
    • Metals above carbon (e.g., aluminum) are extracted by electrolysis.
    • Metals below carbon (e.g., zinc, iron) are extracted by heating with carbon.

Environmental Impact of Copper Mining

  1. Habitat destruction and pollution.
  2. High energy consumption and greenhouse gas emissions.
  3. Continuous demand for copper for renewable energy technologies.

Sustainable Methods of Copper Extraction

  • Recycling: Melting down used copper to create new products.
  • Phytomining: Using plants to absorb copper, which is then harvested for extraction.
  • Copper from Waste: Using sulfuric acid to produce copper sulfate, then promoting displacement reactions to 얻다 copper.