C14

• What is the main use of the earth's resources by human civilization?

  To make products or provide energy
• What are finite resources?

  Resources that will eventually run out
• What are renewable resources?

  Resources that can be replaced as used
• How can biofuels be replaced?

  By growing the plants again
• What are some sources of biofuels?

  • Crops
  • Trees
  • Animal waste
• What health benefits did water treatment and sewage systems provide?

  Led to better health through clean water
• What is the purpose of screening in sewage treatment?

  To remove larger solid objects
• What happens during primary treatment of sewage?

  Solids settle and are collected
• What is the role of bacteria in secondary treatment?

  They feed on dissolved wastes and microbes
• What is the final treatment in sewage processing?

  Allows useful bacteria to settle out
• What is done with sewage sludge after separation?

  Undergoes anaerobic digestion for biogas
• What can be done with dried sewage sludge?

  Used as agricultural fertilizer or biofuel
• What is copper extracted from?

  A mixture of copper ore and carbon
• What happens to copper carbonate when heated?

  It decomposes to produce copper oxide
• What color change occurs when copper carbonate is heated?

  Turns from green to black
• What is the purpose of electrolysis in copper purification?

  To further purify the copper produced
• Why is the impure copper plate used in electrolysis?

  It contains rare metals like gold
• What is the reaction for reducing copper oxide with carbon?

  copper oxide + carbon ⇒ copper + carbon dioxide
• What is the role of carbon in copper extraction?

  It reduces copper oxide to copper metal
• What is bioleaching?

  A technique using bacteria to extract copper
• How does phytomining work?

  Plants extract minerals from soil and concentrate them
• What is the purpose of life cycle assessments (LCA)?

  To assess environmental impact of products

  
• What is a drawback of life cycle assessments?

  Assigned values may be subjective estimates

  
• What are the steps in conducting a life cycle assessment (LCA)?

  1. List all energy and material inputs
  2. Evaluate potential environmental impacts
  3. Interpret results for decision-making

  
• What does the "Reduce" principle entail?

  Buying or making less stuff
• What does "Reuse" mean in the context of waste management?

  Using items again instead of discarding
• What does "Recycle" involve?

  Reprocessing materials into different products
• What is a significant advantage of recycling aluminum?

  It saves 95% energy compared to ore
• What energy saving is achieved by recycling iron and steel?

  50% energy saving
• What negative effects does metal production have on the environment?

  Produces waste rock and polluting gases
• What is a consequence of quarrying for metal production?

  It scars the landscape
• What gases are produced from burning fossil fuels in metal production?

  Polluting gases causing acid rain