Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Clean, dry air is a mixture containing approximately Nitrogen (), Oxygen (), and the remaining consists of noble gases (mainly Argon ), Carbon Dioxide (), and water vapor.
Carbon Monoxide () is a toxic pollutant formed by the incomplete combustion of carbon-containing fuels. It binds to hemoglobin in the blood, preventing the transport of .
Sulfur Dioxide () is produced by the combustion of fossil fuels containing sulfur impurities and by volcanic activity. It leads to acid rain by forming .
Oxides of Nitrogen () are formed in car engines where high temperatures and pressures cause and from the air to react. They contribute to photochemical smog and acid rain ().
Catalytic converters in vehicles use transition metal catalysts (like Platinum or Rhodium) to convert harmful gases like and into less harmful and .
The Greenhouse Effect is caused by gases like and (Methane) absorbing thermal energy (infrared radiation) reflected from the Earth's surface, leading to global warming.
Photosynthesis is the process by which plants remove from the atmosphere: .
📐Formulae
(Formation of Nitrogen Monoxide in engines)
(Reaction in a catalytic converter)
(Combustion of sulfur impurities)
(Formation of sulfuric acid rain)
(Complete combustion of methane)
💡Examples
Problem 1:
Identify the gas responsible for the 'Greenhouse Effect' produced during the decomposition of vegetation in the absence of oxygen, and provide its formula.
Solution:
Methane, .
Explanation:
Anaerobic decomposition (decomposition without oxygen), such as in rice paddy fields or landfill sites, produces methane, which is a potent greenhouse gas.
Problem 2:
State how a catalytic converter removes Nitrogen Monoxide () from exhaust fumes.
Solution:
By reacting it with Carbon Monoxide () to produce and :
Explanation:
The catalytic converter facilitates a redox reaction where Nitrogen Monoxide is reduced to Nitrogen gas and Carbon Monoxide is oxidized to Carbon Dioxide.
Problem 3:
Explain why the presence of Lead () compounds in the atmosphere has decreased in many countries.
Solution:
The transition from leaded to unleaded petrol ().
Explanation:
Lead compounds were previously added to petrol to improve engine performance, but they are toxic and cause brain damage, leading to a global shift toward lead-free fuels.