Chemistry

• What is the balanced symbol equation for photosynthesis?

  6CO2 + 6H2O → C6H12O6 + 6O2
• When did algae first appear?

  2.7 billion years ago
• What did the increase in oxygen from algae and plants lead to?


  Enabled animals to evolve
• What useful substances have been formed as carbon dioxide decreased?

  • Limestone
  • coal
  • crude oil
  • natural gas
• What type of gas maintains the temperature on earth to be high enough to support life?

  Greenhouse gases
• Examples of greenhouse gases

  Water vapour = H2O (g)

  carbon dioxide = CO2

  methane = CH4