Oxygen info.Urgent!! [10分!!]

1. What are the advantages of oxygen?
Oxygen is of great importance in the chemical and the iron and steel industries.
Oxygen is utilized in medicine in the treatment of respiratory diseases.
2. What are the disadvantages of oxygen? [such as make forest fire to burn brightly]
Highly concentrated sources of oxygen promote rapid combustion and therefore are fire and explosion hazards in the presence of fuels. Oxygen itself is not the fuel, but as a reactant, concentrated oxygen may allow combustion to proceed dangerously rapidly.
3. History of oxygen
One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle and surrounding the vessel's neck with water resulted in some water rising into the neck. Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philo's work by observing that a portion of air is consumed during combustion and respiration.
Oxygen's discovery as a separate element was delayed by a philosophy of combustion and corrosion called the phlogiston theory. Established in 1667 by German alchemist J. J. Becher and modified by chemist Georg Ernst Stahl by 1731, phlogiston theory stated that all combustible materials were made of two parts. One part, called phlogiston, was given off when the substance containing it was burned while the dephlogisticated part was thought to be its true form, its calx. Highly combustible materials, such as coal, were made mostly of phlogiston while non-combustible substances, such as iron, contained very little.
Molecular oxygen, O2, is essential for cellular respiration in all aerobic organisms. Almost all animals use hemoglobin in their blood to transport oxygen from their lungs to their tissues.
4. Experiment of oxygen
Oxygen can also be produced through electrolysis of water into oxygen and hydrogen or by heating potassium chlorate with manganese dioxide as a catalyst.
The Winkler test is used to determine the level of dissolved oxygen in water samples. The test was first developed by Lajos Winkler while working on his doctoral dissertation in 1888. The amount of dissolved oxygen is the biological activity of the water masses. Phytoplankton and macroalgae present in the water mass produce oxygen by the way of the photosynthesis. At the same time bacteria and all other organisms (zooplankton, algae, fish) consume the oxygen by respiration. The result of this two mechanisms give the concentration in dissolved oxygen.
5. Info. of oxygen
Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. The gas is colorless, odorless, and tasteless. The liquid and solid forms are a pale blue color and are strongly paramagnetic.
Atomic Number: 8
Atomic Symbol: O
Atomic Weight: 15.9994
Melting Point: -218.79 deg C
Boiling Point: -182.95 deg C
6. Where can we find oxygen?
We can find oxygen in the atmosphere. 21% of the atmosphere is oxygen gas.
7. What are the uses of oxygen?
- one of the life-sustaining elements on Earth and is needed by all animals
- in blast furnaces to make steel
- an important component in the production of many synthetic chemicals, including ammonia, alcohols, and various plastics.
- oxygen and acetylene are combusted together to provide the very high temperatures needed for welding and metal cutting
- utilized in medicine in the treatment of respiratory diseases and is mixed with other gases for respiration in submarines, high-flying aircraft, and spacecraft
- liquid oxygen is used as an oxidizer in the fuel systems of large rockets
8. Oxygen 是什麼組成?
Oxygen gas (O2) is formed by two oxygen atom.
I hope this can help with your understanding. =)