The atmosphere
characteristics of gases
atmospheric composition
treating and treatment of water
environmental implications
extraction of gases
emissions
there is more water vapour in the air around you on a damp day.
we depend on plants for food, and they depend on carbon dioxide. And without nitrogen to dilute the oxygen, fuels would burn too fast for us.
the gas we depend on most is oxygen. We need it for the process called respiration, that goes on in all our cells:
glucose + oxygen → carbon dioxide + water + energy
The energy from respiration keeps us warm, and allows us to move, and enables hundreds of different reactions to go on in our bodies.
noble gases
nitrogen
oxygen
In hospitals, patients with breathing problems are given oxygen
through an oxygen mask, or in an oxygen tent.
Liquid nitrogen is very cold. (It boils at 2196 °C.) So it is used to quick, freeze food in food factories, and to freeze liquid in cracked pipes before repairing them.
unreactive. So it is flushed through food packaging to
remove oxygen and keep the food fresh. (Oxygen helps decay.)
Argon provides the inert atmosphere in ordinary tungsten light bulbs.
Neon is used in advertising signs because it glows red when a current is
passed through it.
Helium is used to fill balloons, since it is very light, and safe.
cobalt chloride for testing water
This treatment can remove even the tiniest particles. And chlorine can kill all the microbes. But the water may still have harmful substances dissolved in it. For example, nitrates from fertilisers, that can make babies ill.
Chlorination
fractional distillation of liquid of air
Extracting of sulfur
Polluntants
Coal and petroleum contain sulfur compounds, even after petroleum is treated to remove them. Some coals contain a high % of sulfur. When these fuels are burned in power stations, and factory furnaces, When these fuels are burned in power stations, and factory furnaces, the sulfur compounds are oxidised to sulfur dioxide.
This escapes into the air, where it can cause a great deal of harm. It can attack your lungs, giving breathing problems. It also dissolves in rain to give acid rain. This attacks buildings and metal structures, and can kill fish and plants.
carbon dioxide
Carbon dioxide and methane are the two main ones we add to the atmosphere, through human activity. There is much more carbon dioxide than methane in the atmosphere.
The level of carbon dioxide is rising because we burn more fossil fuel each year. The carbon dioxide from this goes into the atmosphere. It cannot escape into space, and the ocean can dissolve only some of it.
The level of methane is rising because there is an increase in animal farming, and rice farming, around the world and more and more landfill site.
uses sulfur dioxides
Its main use is in the manufacture of sulfuric acid.
It is used to bleach wool, silk, and wood pulp for making paper.
It is used as a sterilizing agent in making soft drinks and jam, and in drying fruit. It stops the growth of bacteria and moulds.
Most sulfur is now obtained from the sulfur compounds found in petroleum and natural gas. These compounds are removed to help reduce air pollution.