Composition of Air
What percentage of nitrogen is in clean, dry air?
78%
What is the source of carbon dioxide in the atmosphere?
From complete combustion of carbon-containing fuels (like coal, oil, gas)
What is the effect of increased carbon dioxide levels?
Leads to global warming, which contributes to climate change
How does planting trees help reduce climate change?
Trees absorb carbon dioxide through photosynthesis, reducing atmospheric CO₂
What are the products of complete combustion of hydrocarbons?
Carbon dioxide (CO₂) and water (H₂O)
What is the percentage of oxygen in air?
21%
What causes carbon monoxide to form during combustion?
From incomplete combustion of carbon-containing fuels (due to limited oxygen)
Why is carbon monoxide dangerous?
It is a toxic gas that binds to hemoglobin and reduces oxygen transport
How does reducing livestock farming help the environment?
Livestock produce methane, a greenhouse gas; reducing farming lowers emissions
What are the products of incomplete combustion?
Carbon monoxide (CO), particulates (soot), and water (H₂O)
Name two noble gases found in air.
Argon and Neon (or Krypton, Xenon)
Name the main source of methane emissions.
Decomposition of vegetation and animal waste digestion (e.g., from cows)
What health risk is associated with particulates?
Increases the risk of respiratory problems and cancer
Give two examples of renewable energy sources.
Wind energy, solar energy, hydroelectric, geothermal
Write the word equation for burning methane in oxygen.
Methane + Oxygen → Carbon dioxide + Water
What gas makes up approximately 0.04% of air?
Carbon dioxide (CO₂)
What is the source of oxides of nitrogen in the atmosphere?
From car engines, especially at high temperatures
How does methane contribute to climate change?
Methane is a greenhouse gas that traps heat and causes global warming
Why should we decrease fossil fuel use?
Burning fossil fuels releases CO₂ and SO₂, contributing to climate change and acid rain
What is the balanced symbol equation for the complete combustion of methane?
CH₄ + 2O₂ → CO₂ + 2H₂O
Why is air considered a mixture, not a compound?
Because its components (like O₂ and N₂) are not chemically combined and can be separated physically
How does sulfur dioxide enter the atmosphere from fossil fuels?
From combustion of fossil fuels that contain sulfur compounds
Which pollutant is toxic and produced during incomplete combustion?
Carbon monoxide, produced during incomplete combustion
Explain how using hydrogen as a fuel can help reduce pollution.
Hydrogen burns to form only water, producing no CO₂ or toxic gases
Why does incomplete combustion produce carbon monoxide and particulates?
Incomplete combustion happens when there is not enough oxygen, forming CO and soot instead of CO₂