Year 9 Chemistry Revision

Question 1

What gases produced by volcanic activity formed the Earth’s early atmosphere?

Answer 1

Gases produced by volcanic activity formed the Earth’s early atmosphere

These gases included carbon dioxide, water vapor, and small amounts of other gases.

Question 2

What were the main components of the Earth’s early atmosphere?

Answer 2

• A little or no oxygen
• A large amount of carbon dioxide
• Water vapor
• Small amounts of other gases

This composition is based on scientific interpretations of geological evidence.

Question 3

How did condensation of water vapor contribute to the formation of oceans?

Answer 3

Condensation of water vapor formed oceans

As the Earth cooled, the water vapor condensed and accumulated to create bodies of water.

Question 4

What process decreased the amount of carbon dioxide in the atmosphere as oceans formed?

Answer 4

Carbon dioxide dissolved in the oceans

This process helped to lower atmospheric carbon dioxide levels.

Question 5

How did primitive plants affect atmospheric oxygen levels?

Answer 5

Primitive plants used carbon dioxide and released oxygen by photosynthesis

This process gradually increased the amount of oxygen in the atmosphere.

Question 6

What is the greenhouse effect?

Answer 6

Various gases in the atmosphere absorb heat radiated from the Earth and release energy, keeping the Earth warm

Key gases include carbon dioxide, methane, and water vapor.

Question 7

What evidence supports the idea that human activity is causing climate change?

Answer 7

• Correlation between atmospheric carbon dioxide concentration and fossil fuel consumption
• Temperature change

This evidence indicates a link between human activities and climate change.

Question 8

What uncertainties may affect the evidence for climate change?

Answer 8

• Location of measurements
• Historical accuracy

These factors can influence the interpretation of climate data.

Question 9

What potential effects could increased levels of carbon dioxide and methane have on the climate?

Answer 9

• Climate change
• Extreme weather patterns
• Rising sea levels

These effects result from human activities like burning fossil fuels and livestock farming.

Question 10

How might the effects of increased greenhouse gases be mitigated?

Answer 10

Considerations of scale, risk, and environmental implications

Mitigation strategies may involve reducing emissions and enhancing carbon sinks.