AQA GCSE Chemistry (Triple) - Paper 2: The Chemistry of the Atmosphere (Higher Tier, Conceptual Flashcards)

What are the main gases in today’s atmosphere?

Approximately 78% nitrogen, 21% oxygen, and 1% other gases (including carbon dioxide).

What was the early atmosphere like?

Mostly carbon dioxide, with little or no oxygen; contained nitrogen, water vapor, and methane.

What caused the early atmosphere to change?

Volcanic activity released gases, oceans formed as Earth cooled, and carbon dioxide dissolved in the oceans.

How did oxygen first enter the atmosphere?

Through photosynthesis by algae and plants, which released oxygen as a by-product.

How did the formation of oceans affect carbon dioxide levels?

CO2 dissolved in oceans and was used by marine organisms to form shells and skeletons.

How were fossil fuels formed?

From the remains of ancient plants and microorganisms buried under layers of sediment.

What is the greenhouse effect?

A natural process where greenhouse gases trap heat energy in the Earth’s atmosphere.

What are the main greenhouse gases?

Carbon dioxide, methane, and water vapor.

How do greenhouse gases keep Earth warm?

They absorb infrared radiation emitted from the Earth’s surface and re-radiate it back.

What is the difference between the greenhouse effect and global warming?

The greenhouse effect is natural; global warming refers to the enhanced effect caused by human activities.

What human activities increase carbon dioxide levels?

Burning fossil fuels, deforestation, and industrial processes like cement production.

What human activities increase methane levels?

Agriculture (e.g., cattle farming, rice paddies), waste decomposition, and fossil fuel extraction.

What is global climate change?

Long-term changes in the Earth’s temperature and weather patterns due to enhanced greenhouse effect.

What are possible consequences of climate change?

Rising sea levels, melting ice caps, more extreme weather, species extinction, and disruption of ecosystems.

Why is climate change difficult to model accurately?

Because the climate system is complex and influenced by many interdependent factors.

What are carbon footprints?

The total amount