4.9 Chemistry of the atmosphere Flashcards
(15 cards)
What are the main gases in the modern atmosphere?
78% nitrogen, 21% oxygen, with traces of carbon dioxide, argon, and other gases.
What was the early atmosphere like?
Mainly carbon dioxide, with little or no oxygen, and small amounts of ammonia, methane, and water vapour.
How did oxygen levels increase?
Photosynthesis by early algae and plants converted carbon dioxide into oxygen, gradually increasing atmospheric oxygen.
How did carbon dioxide levels decrease?
CO₂ was absorbed by oceans, trapped in sedimentary rocks and fossil fuels, and used by plants in photosynthesis.
What human activities increase atmospheric CO₂?
Burning fossil fuels (e.g., coal, oil, gas), deforestation, and industrial processes.
What is the greenhouse effect?
Greenhouse gases (CO₂, methane, water vapour) trap infrared radiation in the atmosphere, keeping the Earth warm.
Name three greenhouse gases?
Carbon dioxide (CO₂), methane (CH₄), water vapour (H₂O).
What are the potential effects of global climate change?
Rising sea levels, more frequent extreme weather events, changes in rainfall patterns, loss of biodiversity, and crop failures.
What is a carbon footprint?
The total amount of greenhouse gases emitted by human activities, often measured in CO₂ equivalents.
How can carbon footprints be reduced?
Using renewable energy sources (e.g., solar, wind), improving energy efficiency, reducing consumption, carbon capture, and reforestation.
What are the problems with reducing carbon emissions?
Cost, technology limitations, political challenges, and resistance from industries that rely on fossil fuels.
What is incomplete combustion?
When a fuel burns with insufficient oxygen, producing carbon monoxide (CO), soot (carbon), and less energy.
Why is carbon monoxide dangerous?
It is a colourless, odourless gas that binds to haemoglobin in the blood, preventing oxygen transport and causing suffocation.
What pollutants are released when fuels are burned?
Carbon dioxide, water vapour, carbon monoxide, particulates, sulfur dioxide, nitrogen oxides.
What are the effects of sulfur dioxide and nitrogen oxides?
They combine with water vapour to form acids, leading to acid rain, which harms plant life, aquatic systems, and buildings
