Topic 8 – Fuels and Earth Science

• What gases formed the Earth's early atmosphere?

  Gases produced by volcanic activity
• How did volcanic activity contribute to the early atmosphere?

  It released gases that formed the atmosphere
• What was the composition of the early atmosphere similar to?

  Similar to Mars and Venus today
• What was the main gas in the early atmosphere?

  Carbon dioxide (CO2)
• What other gases were produced by volcanoes?

  Nitrogen, methane (CH4), and ammonia (NH3)
• What was the state of oxygen in the early atmosphere?

  Little or no oxygen
• What was the amount of CO2 in the early atmosphere?

  A large amount of CO2
• What was present in the early atmosphere besides CO2?

  Water vapour and small amounts of other gases
• How did oceans form from water vapour?

  Water vapour condensed to form oceans
• What happens to CO2 as oceans formed?

  CO2 dissolved in water and formed sediments
• How did primitive plants affect atmospheric O2 levels?

  They used CO2 and released O2 through photosynthesis
• What is the photosynthesis equation?

  6CO2 + 6H2O -> C6H12O6 + 6O2
• When did algae first produce oxygen?

  About 2.7 billion years ago
• How did the percentage of oxygen change over a billion years?

  It gradually increased to support animal evolution
• How did algae and plants affect CO2 levels?

  They decreased the percentage of CO2 by photosynthesis
• What is the chemical test for oxygen?

  A glowing splint relights in oxygen
• How do greenhouse gases affect Earth's temperature?

  They absorb heat and release energy
• What happens to electromagnetic radiation from the sun?

  It passes through the atmosphere and warms the Earth
• What is the greenhouse effect?

  Warming of the atmosphere due to greenhouse gases
• What evidence supports human activity causing climate change?

  Correlation between CO2 levels and fossil fuel consumption
• What human activities increase CO2 and CH4 levels?

  Driving, electricity consumption, and livestock farming
• What do scientists believe about human activities and climate change?

  They will cause Earth's temperature to increase
• Why is modeling climate change difficult?

  Complex systems lead to simplified models and speculation
• What are the properties of hydrocarbons in different fractions?

  They differ in carbon and hydrogen atoms, boiling points
• How does the size of hydrocarbon molecules affect their properties?

  Shorter molecules are less viscous and more flammable
• What is a homologous series?

  A series of compounds with the same general formula
• How do compounds in a homologous series differ?

  They differ by CH2 in molecular formulae
• What is produced during complete combustion of hydrocarbons?

  CO2 and H2O are produced
• What happens during incomplete combustion of hydrocarbons?

  Carbon and carbon monoxide are produced
• Why is carbon monoxide considered toxic?

  It prevents red blood cells from carrying oxygen
• What problems are caused by incomplete combustion?

  It produces carbon monoxide and soot
• What are the products of burning carbon fuels?

  CO₂ and H₂O
• What type of reaction occurs when carbon fuels are burned?

  Exothermic reaction
• Why does incomplete combustion of hydrocarbons occur?

  Not enough oxygen for complete burning
• What is produced during incomplete combustion of hydrocarbons?

  Carbon and carbon monoxide
• What happens to fuel during partial combustion?

  Some fuel does not burn completely
• What is carbon monoxide?

  A toxic, colorless, odorless gas
• How does carbon monoxide affect the body?

  Prevents red blood cells from carrying oxygen
• What health problems does carbon monoxide cause?

  It can lead to death
• What problems does soot cause in the environment?

  It causes global dimming