The Earths Atmosphere Chemistry GCSE

What is the composition of the earth’s current atmosphere

78% Nitrogen 21% oxygen 1% other gases

What gases were present in earth’s early atmosphere?

Carbon Dioxide, water vapor, nitrogen and small amounts of methane and ammonia, very little or no oxygen.

How did oxygen first appear in earth’s atmosphere

Produced by photosynthetic organisms

What process removed carbon dioxide from earth’s early atmosphere?

dissolving in oceans forming sedimentary rock and photosynthesis

What is the role of photosynthesis in the atmosphere?

Helps absorb carbon dioxide by releasing oxygen regulating the levels of these gases

What is the greenhouse effect

Certain gases trap heat from the sun in the earth’s atmosphere keeping the planet warm enough for life

Name 3 greenhouse gases

carbon dioxide, methane and water vapor

How does CO2 enter the atmosphere?

Respiration, combustion, volcanic activity and deforestation

How does methane enter the atmosphere?

Livestock digestion, rice paddies, fossil fuel extraction and landfill decompostition

Why is the GHE important for life on earth?

Keeps that earth warm enough for life by trapping heat from the sun

What is global warming

increase in the earth’s average temperature due to the enhanced greenhouse effect caused by large amounts of greenhouse gases

what are fossil fuels

energy rich substances from by the remains of sea animals such as coal and oil

Main pollutants produced when burning fossil fuels

carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides and particulates

What is and why is carbon monoxide dangerous?

It’s a colourless and odourless gas produced from an incomplete combustion and prevents red blood cells from caring oxygen

How does sulphur dioxide contribute to acid rain?

It reacts with water vapor forming sulfuric acid falling as acid rain

What are the effects of acid rain on the environment?

Damages ecosystems by acidifying soil and water, harming plants and aquatic life, and destroys buildings

What are nitrogen oxides and how are they formed

Formed when nitrogen and oxygen react at high temps typically in car engines

How do nitrogen oxides contribute to air pollution?

Cause respiratory issues, contribute to smog and forms acid rain

What are particulates and where do they come from?

Tiny particles like soot produced by combustion

How is smog formed?

Pollutants like nitrogen oxides and particulates react in sunlight creating a hazy air mixture reducing visibility

What is the ozone layer and why is it important

How has earths atmosphere changed over time?

Was once dominated by carbon dioxide with no oxygen to it’s current composition with high nitrogen and oxygen levels