Chemistry- Earth and its atmosphere

Question 1

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

Answer 1

Mainly CO2 with little or no O2, nitrogen, small proportions of CH4 and NH3

The early atmosphere may have resembled that of Mars and Venus today.

Question 2

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

Answer 2

Little or no oxygen, large amount of CO2, water vapour, small amounts of other gases

This reflects the conditions during the early formation of the atmosphere.

Question 3

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

Answer 3

Water vapour condensed to form oceans (H2O (g) -> H2O (l))

This process indicates a significant change in the Earth’s surface environment.

Question 4

How did the amount of CO2 in the atmosphere decrease during ocean formation?

Answer 4

CO2 dissolved in water and carbonates were precipitated, producing sediments

This process contributed to a reduction of CO2 levels in the atmosphere.

Question 5

What process did primitive plants use to increase the amount of O2 in the atmosphere?

Answer 5

Photosynthesis, where algae and plants produced O2 from CO2 and H2O

The equation for photosynthesis is 6CO2 + 6H2O -> C6H12O6 + 6O2.

Question 6

When did algae first produce oxygen, and what was the impact?

Answer 6

About 2.7 billion years ago; oxygen began to appear in the atmosphere

This event marked a significant turning point in Earth’s atmospheric composition.

Question 7

What is the chemical test for O2?

Answer 7

A glowing splint inserted into a test tube of the gas relights in oxygen

This test is a common demonstration in chemistry to identify oxygen.

Question 8

Explain the greenhouse effect.

Answer 8

Greenhouse gases absorb heat radiated from the Earth, warming the atmosphere

This process involves electromagnetic radiation from the sun and infrared radiation from the Earth.

Question 9

What human activities are known to increase levels of CO2 and CH4?

Answer 9

Driving, consuming electricity, raising livestock, decay of organic waste in landfills

These activities contribute to climate change by increasing greenhouse gas concentrations.

Question 10

What is one challenge in modeling global climate change?

Answer 10

Complex systems lead to simplified models and speculation

This can result in biased media presentations based on partial evidence.

Question 11

True or False: Increased levels of CO2 and CH4 can have potential effects on the climate.

Answer 11

True

These gases are associated with human activities such as fossil fuel combustion and livestock farming.