Chemistry - CHEMISTRY OF THE ATMOSPHERE (C9)

The Earth’s Early Atmosphere -

What gases made up the early atmosphere?

Mainly carbon dioxide, w/ little / no oxygen, plus nitrogen, water vapour, + methane/ ammonia.

The Earth’s Early Atmosphere -

Where did Earth’s early atmosphere come from?

From volcanic activity releasing gases.

The Earth’s Early Atmosphere -

How did oceans form on Earth?

Water vapour in the atmosphere condensed as Earth cooled.

Changes to the Atmosphere Over Time -

How did carbon dioxide levels decrease over time?

Dissolved in oceans, used by marine organisms to form sedimentary rocks, taken in by photosynthesis.

Changes to the Atmosphere Over Time -

What caused oxygen levels to rise?

Photosynthesis by early algae + plants.

Changes to the Atmosphere Over Time -

Which process produces oxygen + removes carbon dioxide?

Photosynthesis.

Greenhouses Gases & Their Effects -

What are the main greenhouse gases?

Carbon dioxide, methane, + water vapour.

Greenhouses Gases & Their Effects -

How do greenhouse gases cause the Earth to warm up?

They absorb outoging infrared radiation + re-radiate it back to Earth’s surface.

Greenhouses Gases & Their Effects -

What is the greenhouse effect?

The natural process that keeps Earth warm enough to support life.

Greenhouses Gases & Their Effects -

What human activities increase greenhouse gas levels?

Burning fossil fuels (adds CO2), deforestation (less CO2 absorbed), cattle farming & landfills (release methane).

Climate Change -

What is global climate change?

Long-term changes in temperature + weather patterns caused by increased greenhouse gases.

Climate Change -

What are possible effects of climate change?

Rising sea levels, more extreme weather, changes in rainfall patterns, species extinction, food/water insecurity.

Climate Change -

Why is it difficult to fully understand climate change?

It’s a complex system w/ many variables + uncertainties in predictions.

Carbon Footprints & Reducing Emissions -

What is a carbon footprint?

The total amount of carbon dioxide + other greenhouse gases emitted over the full life cycle of a product/event/person.

Carbon Footprints & Reducing Emissions -

How can we reduce our carbon footprint?

Use renewable energy, improve energy efficiency, carbon capture + storage, eat less meat + use public transport.

Carbon Footprints & Reducing Emissions -

Why is reducing carbon emissions difficult?

It may be expensive, affect lifestyles, / need global cooperation.

Air Pollutants from Combustion -

What pollutants are released when fossil fuels burn?

Carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxides, particulates (soot).

Air Pollutants from Combustion -

What are the dangers of carbon monoxide?

It is toxic, colourless, + odourless - can cause death by preventing oxygen transport.

Air Pollutants from Combustion -

What problems do particulates cause?

Global dimming (reflects sunlight), health problems (lung damage).

Air Pollutants from Combustion -

What problems does sulfur dioxide cause?

Acid rain, respiratory problems.

Air Pollutants from Combustion -

How is sulfur dioxide formed?

When sulfur in fuels burns during combustion.

Air Pollutants from Combustion -

How are nitrogen oxides formed?

From the reaction of nitrogen + oxygen in hot car engines.