Chemical processes in the ground, air, and water

Question 1

the circulation of water

Answer 1

evaporation –> condensation –> precipitation –> evaporation (from ocean)
+
transporation –> condensation –> precipitation (from trees)

Question 2

the circulation of carbon

Answer 2

trees absorb CO2 from the atmosphere through photosynthesis –> carbon compound are stored in the ground + the trees are used to feed animals and humans who then breath out CO2
+
decomposing animals and plants + combustion release CO2

Question 3

Greenhouse effect

Answer 3

Solar radiation is trapped in the atmosphere by greenhouse gasses, such as CO2, methane, and water vapor. This is natural and necessary, as the Earth would be much colder without it.
Humans are increasing the greenhouse effect by producing more CO2, methane by burning fossil fuels. This results in climate change, which can have a number of consequences for human living conditions.

Question 4

Purification of water

Answer 4

• Mechanical cleaning. The water is filtered through a grate or through sand.
• Chemical cleaning. A substance is added that causes small particles to clump together and fall to the bottom.
• Biological cleaning. Beneficial bacteria eat organic compounds in the water.
• Disinfection. Bacteria and viruses are killed with chlorine, ozone or UV light.

Question 5

Carbon is…

Answer 5

the building block of all living things.