chemistry atmosphere - C9

Question 1

what gases where in the early atmosphere?

Answer 1

carbon dioxide, nitrogen water vapor
small amounts of methane an ammonia

Question 2

what released the gases in the early atmosphere?

Answer 2

volcanic eruptions

Question 3

how did oceans form?

Answer 3

from water vapour condensing

Question 4

how did carbon dioxide and the oceans interact?

Answer 4

carbon dioxide dissolved into the oceans, it then went though a series of reaction to form carbon precipitates and these formed sediments in the seabed. this removed carbon dioxide from the atmosphere.

Question 5

how did carbon dioxide levels reduce?

Answer 5

plants and algae evolved and used it for photosynthesis
algae evolved 2.7 billion years ago
plants evolved in the next billion years

Question 6

how did fossil fuels from?

Answer 6

when plants, plankton + marine animals die, they fell to the seabed and got buried by layers of sediment
over millions of years, they became compressed and formed sedimentary rock, oil + gas

Question 7

give examples of fossil fuels

Answer 7

crude oil, natural gas, oil and coal

Question 8

how are crude oil and natural gas formed

Answer 8

from dead plankton that get trapped in seabed

Question 9

where does coal come from?

Answer 9

thick plant deposits in seabed
coal is sedimentary rock

Question 10

where does limestone come from?

Answer 10

calcium carbonate deposits hat come from the shells an skeletons of marine organisms
(remember the shells of marine animals contained carbonates from the oceans)

Question 11

how was oxygen formed?

Answer 11

from the photosynthesis of plants

Question 12

what was the result of oxygen in the atmosphere?

Answer 12

more complex life forms could evolve

Question 13

what is a greenhouse gas?

Answer 13

a gas that acts as insulating layer to the earth and makes it warm enough to support life forms

Question 14

give examples of greenhouse gases

Answer 14

carbon dioxide, water vapour and methane

Question 15

how do greenhouse gases keep the earth warm?

Answer 15

-they absorb the long wavelength radiation that the earth reradiates
-this earth does this because of the short wavelength radiation that the sun radiates
-the greenhouse gas particles interact and absorb the long wavelength radiation (because of its longer wavelength)
-this then warms the surface of the earth = greenhouse effect.

Question 16

what human activities contribute to greenhouse gases in the atmosphere?

Answer 16

-deforestation- less trees = less carbon dioxide absorbed
-burning fossil fuels = the locked up carbon is released as carbon dioxide
-agriculture = farm animals produce methane through their digestive processes ( they fart it)
- waste = more land fill sites and waste from agriculture = more carbon dioxide and methane from decomposition

Question 17

what is the result of increased levels of carbon dioxide?

Answer 17

climate change
- evidence that it comes from human activities has been peer-reviewed so its reliable
- its hard to make models and predict about climate change because its so complex and has a lot of variables, its hard to make models that aren’t oversimplified

Question 18

what are some consequences of climate change?

Answer 18

-ice caps melting = increased sea levels = increased flooding
-changes in rainfall patterns = some regions will get too little or too much water