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Oxygen was first discovered in 1774 by the British chemist Joseph Priestley, when he decomposed mercury II oxide into its elements by heating it. Karl Wilhelm Scheel, a Swedish chemist, discovered it when he heated manganese dioxide with concentrated sulfuric acid.. French chemist, Antoine Laurent Lavoisier, proved it was an elemental gas, through his experiments on combustion. He also gave oxygen its name. In 1929, W.F. Giaque and H.L. Johnston announced the discovery of two isotopes of oxygen, with mass Oxygen is a colorless, odorless, tasteless gas, located in group VIa of the periodic table. It is slightly denser than air. It is a poor conductor of heat and electricity, and slightly soluble in water. Oxygen also supports combustion, but does not burn. Its atomic number is 8. Its atomic mass is 15.9994. Oxygen melts at -218.4 C and boils at -183 C. It contains 8 protons, electrons, and neurtons. It is also classified as a nonmetal, which has 2 energy levels. It is also slightly magnetic and not harmful at all. Oxygen can be condensed to a pale blue liquid, which is very magnetic. It is produced by compressing the liquid. Oxygen used to be the official standard for the atomic weights of elements. The chemists used natural oxygen, to which the value of 16 was assigned. In 1961, however, carbon-12 replaced oxygen as the standard. There are only three allotropic forms of oxygen known today. There is ordinary oxygen, which contains two atoms per molecule. Its formula is O2. Ordinary oxygen is relatively reactive and combines with most elements to form oxides. O2 is required for us to breathe. Ozone, on the other hand, contains three atoms per molecule. Its formula is O3. Ozone is formed when oxygen in the air is subjected to an electrical discharge, such as a bolt of lightning. Ozone is considered a pollutant, because is attacks structural materials and the tissues of plants and animals. However, it does absorb a great deal of the ultraviolet radiation from the sun. It is also a colorless gas containing a strong, irritating odor. There is also O4, which contains four atoms per molecule. It is in a pale blue, nonmagnetic form, which can be easily broken down into ordinary oxygen. Oxygen combines with most elements, except the lower-atomic-weight noble gases, to form oxides. An oxide is a compound formed by the union of oxygen with another element. Hydrogen combines with oxygen to form hydrogen oxide, also known as ordinary water. Many oxides occur in nature. Water is the most common one. Carbon dioxide is also a common oxide in nature. When oxygen reacts with the metals of Groups I and II, high temperatures are required to start reactions with the lower-atomic-weight metals, such as lithium, sodium, potassium, magnesium, and calcium. The higher-atomic-weight metals, like rubidium, cesium, strontium, and barium, react spontaneously at room temperature. The electronegativity differences between oxygen and each of these metals is large. The oxygen compounds formed with them are ionic. When oxygen reacts with nonmetals, they usually occur at high temperatures of combustion, because the electronegativity differences between them are small. The oxides that result from them, contain covalent bonds and exist as molecules. When oxygen reacts with metals other than those of Groups I and II, they may occur slowly at room temperature. However, some may react rapidly if the temperature is raised. When oxygen and certain types of molds and bacteria are present, decay can occur. Decay is a form of oxidation. Through decay, dead plant and animal materials are reconverted into carbon dioxide, water, and simple mineral compounds. New generations of plants and animals now have space to live. Through the oxygen cycle, oxygen can be used over and over again. When plants take in carbon dioxide during photosynthesis, water molecules are split and oxygen is released into the atmosphere. Oxygen is also produced commercially, by the fractional distillation of liquid air. In this process, air is liquefied and allowed to evaporate. The nitrogen in the liquid air is more volatile and boils off first, leaving the oxygen. Oxygen can even be prepared in a laboratory by using salts such as potassium chlorate, barium peroxide, and sodium peroxide. You can also decompose hydrogen peroxide to produce oxygen. You may also prepare oxygen by the electrolysis of water. In this process, a direct current of electricity is passed through the water. As the current flows, oxygen gas collects at the positive terminal, while hydrogen collects at the negative terminal. Oxygen has many uses today. Most of it produced today is utilized to make a mixture of carbon monoxide and hydrogen, called synthesis gas. It is used for the synthesis of methanol and ammonia. High purity oxygen is used in the metal-fabrication industries. In its liquid form, oxygen is used as a propellant for guided missiles and rockets. Today, we use large amounts of oxygen in high-temperature welding torches. The oxygen mixes with another gas, which produces a flame much warmer than by burning gas in the air. We also administer oxygen to patients whose respiratory functions are impaired. We must also supply persons in high-flying aircrafts with oxygen. Oxygen is even used in open-hearth furnaces for steel manufacturing. As you can tell through this report, oxygen is a very important element. Without it, we would not be alive today. Oxygen plays an important role in our everyday lives. So the next time you are playing your favorite sport, watching your favorite television show, or just relaxing on your couch, remember that without oxygen, none of it would be Bibliography: Word Count: 1001
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