1. Breath Of Fire 3 Deutsch Iso

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. Oxygen is a with symbol O and 8. It is a member of the on the, a highly, and an that readily forms with most elements as well as with other. By mass, oxygen is the third- in the universe, after and. At, two atoms of the element to form, a colorless and odorless with the formula O 2.

Diatomic oxygen gas constitutes 20.8% of the. As compounds including oxides, the element makes up almost half of the. Dioxygen is used in and many major classes of in contain oxygen, such as, and, as do the major constituent of animal shells, teeth, and bone. Most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. Oxygen is continuously replenished by, which uses the energy of sunlight to produce oxygen from water and carbon dioxide.

Oxygen is too chemically reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ( O 3), strongly absorbs ultraviolet radiation and the high-altitude helps protect the from. But ozone is a pollutant near the surface where it is a by-product of.

Oxygen was discovered independently by, in, in 1773 or earlier, and in, in 1774, but Priestley is often given priority because his work was published first. The name oxygen was coined in 1777 by, whose experiments with oxygen helped to discredit the then-popular of and. Its name derives from the roots ὀξύς oxys, 'acid', literally 'sharp', referring to the of and -γενής -genes, 'producer', literally 'begetter', because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition. Common uses of oxygen include residential, production of, and, of steels and other, and in, and. Contents. History Early experiments One of the first known experiments on the relationship between and air was conducted by the 2nd century BCE writer on mechanics,.

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 and thus were able to escape through pores in the glass.

Many centuries later built on Philo's work by observing that a portion of air is consumed during combustion and. In the late 17th century, proved that air is necessary for combustion. English chemist (1641–1679) refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. In one experiment, he found that placing either a mouse or a lit candle in a closed container over water caused the water to rise and replace one-fourteenth of the air's volume before extinguishing the subjects. From this he surmised that nitroaereus is consumed in both respiration and combustion. Mayow observed that increased in weight when heated, and inferred that the nitroaereus must have combined with it. He also thought that the lungs separate nitroaereus from air and pass it into the blood and that animal heat and muscle movement result from the reaction of nitroaereus with certain substances in the body.

Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract 'De respiratione'. Phlogiston theory. Main article:, and all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a.

This may have been in part due to the prevalence of the philosophy of combustion and called the phlogiston theory, which was then the favored explanation of those processes. Established in 1667 by the German alchemist, and modified by the chemist 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,. Highly combustible materials that leave little, such as wood or coal, were thought to be made mostly of phlogiston; non-combustible substances that corrode, such as iron, contained very little.

Air did not play a role in phlogiston theory, nor were any initial quantitative experiments conducted to test the idea; instead, it was based on observations of what happens when something burns, that most common objects appear to become lighter and seem to lose something in the process. Is usually given priority in the discovery. Oxygen was first discovered by Swedish pharmacist. He had produced oxygen gas by heating mercuric oxide and various in 1771–2.

Scheele called the gas 'fire air' because it was the only known supporter of combustion, and wrote an account of this discovery in a manuscript he titled Treatise on Air and Fire, which he sent to his publisher in 1775. That document was published in 1777. In the meantime, on August 1, 1774, an experiment conducted by the British clergyman focused sunlight on (HgO) inside a glass tube, which liberated a gas he named 'dephlogisticated air'. He noted that candles burned brighter in the gas and that a mouse was more active and lived longer while breathing it. After breathing the gas himself, he wrote: 'The feeling of it to my lungs was not sensibly different from that of common air, but I fancied that my breast felt peculiarly light and easy for some time afterwards.'

Priestley published his findings in 1775 in a paper titled 'An Account of Further Discoveries in Air' which was included in the second volume of his book titled. Because he published his findings first, Priestley is usually given priority in the discovery. The French chemist later claimed to have discovered the new substance independently. Priestley visited Lavoisier in October 1774 and told him about his experiment and how he liberated the new gas. Scheele also posted a letter to Lavoisier on September 30, 1774 that described his discovery of the previously unknown substance, but Lavoisier never acknowledged receiving it (a copy of the letter was found in Scheele's belongings after his death). And a liquid oxygen-gasoline 's original presumed that all elements were monatomic and that the atoms in compounds would normally have the simplest atomic ratios with respect to one another. For example, Dalton assumed that water's formula was HO, giving the of oxygen was 8 times that of hydrogen, instead of the modern value of about 16.

In 1805, and showed that water is formed of two volumes of hydrogen and one volume of oxygen; and by 1811 had arrived at the correct interpretation of water's composition, based on what is now called and the diatomic elemental molecules in those gases. By the late 19th century scientists realized that air could be liquefied and its components isolated by compressing and cooling it. Using a method, Swiss chemist and physicist liquid in order to liquefy carbon dioxide, which in turn was evaporated to cool oxygen gas enough to liquefy it. He sent a telegram on December 22, 1877 to the in Paris announcing his discovery of. Just two days later, French physicist announced his own method of liquefying molecular oxygen. Only a few drops of the liquid were produced in each case and no meaningful analysis could be conducted. Oxygen was liquified in a stable state for the first time on March 29, 1883 by Polish scientists from, and.

In 1891 Scottish chemist was able to produce enough liquid oxygen for study. The first commercially viable process for producing liquid oxygen was independently developed in 1895 by German engineer and British engineer William Hampson. Both men lowered the temperature of air until it liquefied and then the component gases by boiling them off one at a time and capturing them separately. Later, in 1901, oxyacetylene was demonstrated for the first time by burning a mixture of and compressed O 2. This method of welding and cutting metal later became common.

In 1923, the American scientist became the first person to develop a that burned liquid fuel; the engine used for fuel and liquid oxygen as the. Goddard successfully flew a small liquid-fueled rocket 56 m at 97 km/h on March 16, 1926 in, US. Oxygen levels in the atmosphere are trending slightly downward globally, possibly because of fossil-fuel burning. Characteristics Properties and molecular structure. Orbital diagram, after Barrett (2002), showing the participating atomic orbitals from each oxygen atom, the molecular orbitals that result from their overlap, and the filling of the orbitals with the 12 electrons, 6 from each O atom, beginning from the lowest energy orbitals, and resulting in covalent double bond character from filled orbitals (and cancellation of the contributions of the pairs of σ and σ. and π and π. orbital pairs).

At, oxygen is a colorless, odorless, and tasteless gas with the O 2, referred to as dioxygen. As dioxygen, two oxygen atoms are to each other. The bond can be variously described based on level of theory, but is reasonably and simply described as a covalent that results from the filling of formed from the of the individual oxygen atoms, the filling of which results in a of two. More specifically, the double bond is the result of sequential, low-to-high energy, or, filling of orbitals, and the resulting cancellation of contributions from the 2s electrons, after sequential filling of the low σ and σ. orbitals; σ overlap of the two atomic 2p orbitals that lie along the O-O molecular axis and π overlap of two pairs of atomic 2p orbitals perpendicular to the O-O molecular axis, and then cancellation of contributions from the remaining two of the six 2p electrons after their partial filling of the lowest π and π. orbitals. This combination of cancellations and σ and π overlaps results in dioxygen's double bond character and reactivity, and a triplet electronic.

An with two unpaired electrons, as is found in dioxygen orbitals (see the filled π. orbitals in the diagram) that are of equal energy—i.e., —is a configuration termed a state. Hence, the ground state of the O 2 molecule is referred to as. The highest energy, partially filled orbitals are, and so their filling weakens the bond order from three to two. Because of its unpaired electrons, triplet oxygen reacts only slowly with most organic molecules, which have paired electron spins; this prevents spontaneous combustion. Liquid oxygen, temporarily suspended in a magnet owing to its paramagnetism In the triplet form, O 2 molecules are. That is, they impart magnetic character to oxygen when it is in the presence of a magnetic field, because of the of the unpaired electrons in the molecule, and the negative between neighboring O 2 molecules.

Liquid oxygen is so that, in laboratory demonstrations, a bridge of liquid oxygen may be supported against its own weight between the poles of a powerful magnet. Is a name given to several higher-energy species of molecular O 2 in which all the electron spins are paired. It is much more reactive with common than is molecular oxygen per se. In nature, singlet oxygen is commonly formed from water during photosynthesis, using the energy of sunlight. It is also produced in the by the photolysis of ozone by light of short wavelength, and by the as a source of active oxygen.

In photosynthetic organisms (and possibly animals) play a major role in absorbing energy from and converting it to the unexcited ground state before it can cause harm to tissues. Representation of dioxygen (O 2) molecule The common of elemental oxygen on Earth is called, O 2, the major part of the Earth's atmospheric oxygen (see ).

O 2 has a bond length of 121 and a bond energy of 498, which is smaller than the energy of other double bonds or pairs of single bonds in the and responsible for the reaction of O 2 with any organic molecule. Due to its energy content, O 2 is used by complex forms of life, such as animals, in. Other aspects of O 2 are covered in the remainder of this article.

Trioxygen ( O 3) is usually known as and is a very reactive allotrope of oxygen that is damaging to lung tissue. Ozone is produced in the when O 2 combines with atomic oxygen made by the splitting of O 2 by (UV) radiation. Since ozone absorbs strongly in the UV region of the, the of the upper atmosphere functions as a protective radiation shield for the planet. Near the Earth's surface, it is a formed as a by-product of.

At altitudes, sufficient atomic oxygen is present to cause. The molecule ( O 4) was discovered in 2001, and was assumed to exist in one of the six phases of. It was proven in 2006 that this phase, created by pressurizing O 2 to 20, is in fact a O 8. This cluster has the potential to be a much more powerful than either O 2 or O 3 and may therefore be used in.

A metallic phase was discovered in 1990 when solid oxygen is subjected to a pressure of above 96 GPa and it was shown in 1998 that at very low temperatures, this phase becomes. Physical properties. See also: and Oxygen more readily in water than nitrogen, and in freshwater more readily than seawater. Water in equilibrium with air contains approximately 1 molecule of dissolved O 2 for every 2 molecules of N 2 (1:2), compared with an atmospheric ratio of approximately 1:4. The solubility of oxygen in water is temperature-dependent, and about twice as much (14.6 mgL −1) dissolves at 0 °C than at 20 °C (7.6 mgL −1).

At 25 °C and 1 (101.3 ) of air, freshwater contains about 6.04 (mL) of oxygen per, and contains about 4.95 mL per liter. At 5 °C the solubility increases to 9.0 mL (50% more than at 25 °C) per liter for water and 7.2 mL (45% more) per liter for sea water. Oxygen gas dissolved in water at sea-level 5 °C 25 °C Freshwater 9.0 mL 6.04 mL Seawater 7.2 mL 4.95 mL Oxygen condenses at 90.20 (−182.95 °C, −297.31 °F), and freezes at 54.36 K (−218.79 °C, −361.82 °F). Both and O 2 are clear substances with a light color caused by absorption in the red (in contrast with the blue color of the sky, which is due to of blue light). High-purity liquid O 2 is usually obtained by the of liquefied air. Liquid oxygen may also be condensed from air using liquid nitrogen as a coolant. Oxygen is a highly reactive substance and must be segregated from combustible materials.

The spectroscopy of molecular oxygen is associated with the atmospheric processes of and. The absorption in the and in the ultraviolet produces atomic oxygen that is important in the chemistry of the middle atmosphere. Excited state singlet molecular oxygen is responsible for red chemiluminescence in solution. Isotopes and stellar origin. Late in a massive star's life, 16O concentrates in the O-shell, 17O in the H-shell and 18O in the He-shell.

Naturally occurring oxygen is composed of three stable, and, with 16O being the most abundant (99.762% ). Most 16O is at the end of the process in massive but some is made in the.

Breath Of Fire 3 Deutsch Iso

17O is primarily made by the burning of hydrogen into during the, making it a common isotope in the hydrogen burning zones of stars. Most 18O is produced when (made abundant from CNO burning) captures a nucleus, making 18O common in the helium-rich zones of. Fourteen have been characterized. The most stable are 15O with a of 122.24 seconds and 14O with a half-life of 70.606 seconds. All of the remaining isotopes have half-lives that are less than 27 s and the majority of these have half-lives that are less than 83 milliseconds. The most common of the isotopes lighter than 16O is to yield nitrogen, and the most common mode for the isotopes heavier than 18O is to yield. Oxygen is the most abundant chemical element by mass in the Earth's, air, sea and land.

Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. About 0.9% of the 's mass is oxygen. Oxygen constitutes 49.2% of the by mass as part of oxide compounds such as and is the most abundant element by mass in the. It is also the major component of the world's oceans (88.8% by mass).

Oxygen gas is the second most common component of the, taking up 20.8% of its volume and 23.1% of its mass (some 10 15 tonnes). Earth is unusual among the planets of the in having such a high concentration of oxygen gas in its atmosphere: (with 0.1% O 2 by volume) and have much less. The O 2 surrounding those planets is produced solely by the action of ultraviolet radiation on oxygen-containing molecules such as carbon dioxide. The unusually high concentration of oxygen gas on Earth is the result of the. This describes the movement of oxygen within and between its three main reservoirs on Earth: the atmosphere, the biosphere, and the. The main driving factor of the oxygen cycle is, which is responsible for modern Earth's atmosphere. Photosynthesis releases oxygen into the atmosphere, while, and combustion remove it from the atmosphere.

In the present equilibrium, production and consumption occur at the same rate. Cold water holds more dissolved O 2. Free oxygen also occurs in solution in the world's water bodies. The increased solubility of O 2 at lower temperatures (see ) has important implications for ocean life, as polar oceans support a much higher density of life due to their higher oxygen content.

With plant nutrients such as or may stimulate growth of algae by a process called and the decay of these organisms and other biomaterials may reduce the O 2 content in eutrophic water bodies. Scientists assess this aspect of water quality by measuring the water's, or the amount of O 2 needed to restore it to a normal concentration. 500 million years of vs 18O measure the ratio of oxygen-18 and oxygen-16 in the and of marine organisms to determine the climate millions of years ago (see ). Molecules that contain the lighter, oxygen-16, evaporate at a slightly faster rate than water molecules containing the 12% heavier oxygen-18, and this disparity increases at lower temperatures.

During periods of lower global temperatures, snow and rain from that evaporated water tends to be higher in oxygen-16, and the seawater left behind tends to be higher in oxygen-18. Marine organisms then incorporate more oxygen-18 into their skeletons and shells than they would in a warmer climate. Paleoclimatologists also directly measure this ratio in the water molecules of samples as old as hundreds of thousands of years. Have measured the relative quantities of oxygen isotopes in samples from the, the, and, but were long unable to obtain reference values for the isotope ratios in the, believed to be the same as those of the. Analysis of a wafer exposed to the in space and returned by the crashed has shown that the Sun has a higher proportion of oxygen-16 than does the Earth.

The measurement implies that an unknown process depleted oxygen-16 from the Sun's prior to the coalescence of dust grains that formed the Earth. Oxygen presents two spectrophotometric peaking at the wavelengths 687 and 760. Some scientists have proposed using the measurement of the radiance coming from vegetation canopies in those bands to characterize plant health status from a platform. This approach exploits the fact that in those bands it is possible to discriminate the vegetation's from its, which is much weaker. The measurement is technically difficult owing to the low and the physical structure of vegetation; but it has been proposed as a possible method of monitoring the from satellites on a global scale. Photosynthesis splits water to liberate O 2 and fixes CO 2 into sugar in what is called a. In nature, free oxygen is produced by the of water during oxygenic.

According to some estimates, and in marine environments provide about 70% of the free oxygen produced on Earth, and the rest is produced by terrestrial plants. Other estimates of the oceanic contribution to atmospheric oxygen are higher, while some estimates are lower, suggesting oceans produce 45% of Earth's atmospheric oxygen each year. A simplified overall formula for photosynthesis is: 6 CO 2 + 6 H 2O + → C 6H 12O 6 + 6 O 2 or simply + water + sunlight → + dioxygen Photolytic occurs in the of photosynthetic organisms and requires the energy of four. Many steps are involved, but the result is the formation of a gradient across the thylakoid membrane, which is used to synthesize (ATP) via. The O 2 remaining (after production of the water molecule) is released into the atmosphere.

Oxygen is used in to generate ATP during. The reaction for aerobic respiration is essentially the reverse of photosynthesis and is simplified as: C 6H 12O 6 + 6 O 2 → 6 CO 2 + 6 H 2O + 2880 kJmol −1 In, O 2 through membranes in the lungs and into. Binds O 2, changing color from bluish red to bright red ( CO 2 is released from another part of hemoglobin through the ). Other animals use ( and some ) or ( and ). A liter of blood can dissolve 200 cm 3 of O 2. Until the discovery of, oxygen was thought to be a requirement for all complex life., such as ion ( O − 2) and ( H 2O 2), are reactive by-products of oxygen use in organisms.

Parts of the of higher organisms create peroxide, superoxide, and singlet oxygen to destroy invading microbes. Reactive oxygen species also play an important role in the of plants against pathogen attack. Oxygen is damaging to, which were the dominant form of on Earth until O 2 began to accumulate in the about 2.5 billion years ago during the, about a billion years after the first appearance of these organisms.

An adult human at rest 1.8 to 2.4 grams of oxygen per minute. This amounts to more than 6 billion tonnes of oxygen inhaled by humanity per year. Living organisms of oxygen in the human body (PO 2) Unit Alveolar blood gas 14.2 11 -13 4.0 -5.3 107 75 -100 30 -40 The free oxygen in the body of a living vertebrate organism is highest in the, and decreases along any, peripheral tissues, and, respectively.

Partial pressure is the pressure that oxygen would have if it alone occupied the volume. Build-up in the atmosphere.

O 2 build-up in Earth's atmosphere: 1) no O 2 produced; 2) O 2 produced, but absorbed in oceans & seabed rock; 3) O 2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4–5) O 2 sinks filled and the gas accumulates Free oxygen gas was almost nonexistent in before photosynthetic and evolved, probably about 3.5 billion years ago. Free oxygen first appeared in significant quantities during the eon (between 3.0 and 2.3 billion years ago).

For the first billion years, any free oxygen produced by these organisms combined with dissolved in the oceans to form. When such oxygen sinks became saturated, free oxygen began to from the oceans 3–2.7 billion years ago, reaching 10% of its present level around 1.7 billion years ago. The presence of large amounts of dissolved and free oxygen in the oceans and atmosphere may have driven most of the extant to during the ( oxygen catastrophe) about 2.4 billion years ago. Using O 2 enables to produce much more than anaerobic organisms. Cellular respiration of O 2 occurs in all, including all complex multicellular organisms such as plants and animals. Since the beginning of the period 540 million years ago, atmospheric O 2 levels have fluctuated between 15% and 30% by volume.

Towards the end of the period (about 300 million years ago) atmospheric O 2 levels reached a maximum of 35% by volume, which may have contributed to the large size of insects and amphibians at this time. Variations in atmospheric oxygen concentration have shaped past climates. When oxygen declined, atmospheric density dropped, which in turn increased surface evaporation, causing precipitation increases and warmer temperatures. At the current rate of photosynthesis it would take about 2,000 years to regenerate the entire O 2 in the present atmosphere. See also:, and One hundred million tonnes of O 2 are extracted from air for industrial uses annually by two primary methods.

The most common method is of liquefied air, with N 2 as a vapor while O 2 is left as a liquid. The other primary method of producing O 2 is passing a stream of clean, dry air through one bed of a pair of identical molecular sieves, which absorbs the nitrogen and delivers a gas stream that is 90% to 93% O 2. Simultaneously, nitrogen gas is released from the other nitrogen-saturated zeolite bed, by reducing the chamber operating pressure and diverting part of the oxygen gas from the producer bed through it, in the reverse direction of flow. After a set cycle time the operation of the two beds is interchanged, thereby allowing for a continuous supply of gaseous oxygen to be pumped through a pipeline.

This is known as. Oxygen gas is increasingly obtained by these non- technologies (see also the related ). Oxygen gas can also be produced through into molecular oxygen and hydrogen.

DC electricity must be used: if AC is used, the gases in each limb consist of hydrogen and oxygen in the explosive ratio 2:1. A similar method is the electrocatalytic O 2 evolution from oxides and. Chemical catalysts can be used as well, such as in or oxygen candles that are used as part of the life-support equipment on submarines, and are still part of standard equipment on commercial airliners in case of depressurization emergencies. Another air separation method is forcing air to dissolve through membranes based on by either high pressure or an electric current, to produce nearly pure O 2 gas.

Oxygen and compressed gas cylinders with regulators methods include high pressure, cryogenics and chemical compounds. For reasons of economy, oxygen is often transported in bulk as a liquid in specially insulated tankers, since one of liquefied oxygen is equivalent to 840 liters of gaseous oxygen at atmospheric pressure and 20 °C (68 °F). Such tankers are used to refill bulk liquid oxygen storage containers, which stand outside hospitals and other institutions that need large volumes of pure oxygen gas. Liquid oxygen is passed through, which convert the cryogenic liquid into gas before it enters the building. Oxygen is also stored and shipped in smaller cylinders containing the compressed gas; a form that is useful in certain portable medical applications and.

Main article: Uptake of O 2 from the air is the essential purpose of, so oxygen supplementation is used in. Treatment not only increases oxygen levels in the patient's blood, but has the secondary effect of decreasing resistance to blood flow in many types of diseased lungs, easing work load on the heart. Is used to treat, some heart disorders , some disorders that cause increased, and any that impairs the body's ability to take up and use gaseous oxygen. Treatments are flexible enough to be used in hospitals, the patient's home, or increasingly by portable devices. Were once commonly used in oxygen supplementation, but have since been replaced mostly by the use of. (high-pressure) medicine uses special to increase the of O 2 around the patient and, when needed, the medical staff., and (the 'bends') are sometimes addressed with this therapy. Increased O 2 concentration in the lungs helps to displace from the heme group of.

Oxygen gas is poisonous to the that cause gas gangrene, so increasing its partial pressure helps kill them. Decompression sickness occurs in divers who decompress too quickly after a dive, resulting in bubbles of inert gas, mostly nitrogen and helium, forming in the blood. Increasing the pressure of O 2 as soon as possible helps to redissolve the bubbles back into the blood so that these excess gasses can be exhaled naturally through the lungs.

Low pressure pure O 2 is used in. An application of O 2 as a low-pressure is in modern, which surround their occupant's body with the breathing gas.

These devices use nearly pure oxygen at about one-third normal pressure, resulting in a normal blood partial pressure of O 2. This trade-off of higher oxygen concentration for lower pressure is needed to maintain suit flexibility. And and also rely on artificially delivered O 2. Submarines, submersibles and usually operate at normal atmospheric pressure. Breathing air is scrubbed of carbon dioxide by chemical extraction and oxygen is replaced to maintain a constant partial pressure. Divers breathe air or gas mixtures with an oxygen fraction suited to the operating depth.

Pure or nearly pure O 2 use in diving at pressures higher than atmospheric is usually limited to, or at relatively shallow depths (6 meters depth, or less), or at pressures up to 2.8 bar, where acute oxygen toxicity can be managed without the risk of drowning. Deeper diving requires significant dilution of O 2 with other gases, such as nitrogen or helium, to prevent. People who climb mountains or fly in non-pressurized sometimes have supplemental O 2 supplies. Pressurized commercial airplanes have an emergency supply of O 2 automatically supplied to the passengers in case of cabin depressurization. Sudden cabin pressure loss activates above each seat, causing to drop.

Pulling on the masks 'to start the flow of oxygen' as cabin safety instructions dictate, forces iron filings into the inside the canister. A steady stream of oxygen gas is then produced by the reaction.

Oxygen, as a supposed mild, has a history of recreational use in and in. Oxygen bars are establishments found in Japan, and, since the late 1990s that offer higher than normal O 2 exposure for a fee.

Professional athletes, especially in, sometimes go off-field between plays to don oxygen masks to boost performance. The pharmacological effect is doubted; a effect is a more likely explanation. Available studies support a performance boost from oxygen enriched mixtures only if it is breathed during aerobic exercise. Other recreational uses that do not involve breathing include applications, such as 's five-second ignition of grills. Most commercially produced O 2 is used to into. Of into consumes 55% of commercially produced oxygen. In this process, O 2 is injected through a high-pressure lance into molten iron, which removes impurities and excess as the respective oxides, SO 2 and CO 2.

The reactions are, so the temperature increases to 1,700 °. Another 25% of commercially produced oxygen is used by the chemical industry. Is reacted with O 2 to create, which, in turn, is converted into; the primary feeder material used to manufacture a host of products, including and polymers (the precursors of many and ). Most of the remaining 20% of commercially produced oxygen is used in medical applications, as an oxidizer in, and in. Oxygen is used in burning with O 2 to produce a very hot flame. In this process, metal up to 60 cm (24 in) thick is first heated with a small oxy-acetylene flame and then quickly cut by a large stream of O 2. ( H 2O) is the most familiar oxygen compound.

The of oxygen is −2 in almost all known compounds of oxygen. The oxidation state −1 is found in a few compounds such as. Compounds containing oxygen in other oxidation states are very uncommon: −1/2 , −1/3 , 0 (, ), +1/2 , +1 , and +2. Oxides and other inorganic compounds ( H 2O) is an oxide of and the most familiar oxygen compound. Hydrogen atoms are to oxygen in a water molecule but also have an additional attraction (about 23.3 kJmol −1 per hydrogen atom) to an adjacent oxygen atom in a separate molecule. These between water molecules hold them approximately 15% closer than what would be expected in a simple liquid with just.

Oxides, such as or, form when oxygen combines with other elements. Due to its, oxygen forms with almost all other elements to give corresponding. The surface of most metals, such as and, are oxidized in the presence of air and become coated with a thin film of oxide that the metal and slows further. Many oxides of the are, with slightly less metal than the would show. For example, the mineral is written as Fe 1 − xO, where x is usually around 0.05.

Oxygen is present in the atmosphere in trace quantities in the form of ( CO 2). The is composed in large part of oxides of ( SiO 2, as found in and ), aluminium ( Al 2O 3, in and ), iron ( Fe 2O 3, in and ), and (in ). The rest of the Earth's crust is also made of oxygen compounds, in particular various complex (in ). The Earth's mantle, of much larger mass than the crust, is largely composed of silicates of magnesium and iron. Water- silicates in the form of Na 4SiO 4, Na 2SiO 3, and Na 2Si 2O 5 are used as and. Oxygen also acts as a for transition metals, forming, which feature metal– O 2. This class of compounds includes the proteins and.

An exotic and unusual reaction occurs with, which oxidizes oxygen to give O 2 +PtF 6 −. Organic compounds. Hydrogen Among the most important classes of organic compounds that contain oxygen are (where 'R' is an organic group): (R-OH); (R-O-R); (R-CO-R); (R-CO-H); (R-COOH); (R-COO-R); (R-CO-O-CO-R); and ( R-C(O)-NR 2). There are many important organic that contain oxygen, including:, and. Acetone ( (CH 3) 2CO) and ( C 6H 5OH) are used as feeder materials in the synthesis of many different substances.

Other important organic compounds that contain oxygen are:, and. Are ethers in which the oxygen atom is part of a ring of three atoms. The element is similarly found in almost all that are important to (or generated by) life. Oxygen reacts spontaneously with many compounds at or below room temperature in a process called. Most of the that contain oxygen are not made by direct action of O 2. Organic compounds important in industry and commerce that are made by direct oxidation of a precursor include and.

Safety and precautions The standard rates compressed oxygen gas as nonhazardous to health, nonflammable and nonreactive, but an oxidizer. Refrigerated liquid oxygen (LOX) is given a health hazard rating of 3 (for increased risk of from condensed vapors, and for hazards common to cryogenic liquids such as frostbite), and all other ratings are the same as the compressed gas form. Main symptoms of oxygen toxicity Oxygen gas ( O 2) can be at elevated, leading to and other health problems. Oxygen toxicity usually begins to occur at partial pressures more than 50 kilo (kPa), equal to about 50% oxygen composition at standard pressure or 2.5 times the normal sea-level O 2 partial pressure of about 21 kPa. This is not a problem except for patients on, since gas supplied through in medical applications is typically composed of only 30%–50% O 2 by volume (about 30 kPa at standard pressure). At one time, were placed in incubators containing O 2-rich air, but this practice was discontinued after some babies were blinded by the oxygen content being too high.

Breathing pure O 2 in space applications, such as in some modern space suits, or in early spacecraft such as, causes no damage due to the low total pressures used. In the case of spacesuits, the O 2 partial pressure in the breathing gas is, in general, about 30 kPa (1.4 times normal), and the resulting O 2 partial pressure in the astronaut's arterial blood is only marginally more than normal sea-level O 2 partial pressure.

Oxygen toxicity to the lungs and can also occur in deep and. Prolonged breathing of an air mixture with an O 2 partial pressure more than 60 kPa can eventually lead to permanent. Exposure to a O 2 partial pressures greater than 160 kPa (about 1.6 atm) may lead to convulsions (normally fatal for divers). Acute oxygen toxicity (causing seizures, its most feared effect for divers) can occur by breathing an air mixture with 21% O 2 at 66 m (217 ft) or more of depth; the same thing can occur by breathing 100% O 2 at only 6 m (20 ft).

Combustion and other hazards. The interior of the Command Module. Pure O 2 at higher than normal pressure and a spark led to a fire and the loss of the crew.

Highly concentrated sources of oxygen promote rapid combustion. And hazards exist when concentrated oxidants and are brought into close proximity; an ignition event, such as heat or a spark, is needed to trigger combustion.

Oxygen is the oxidant, not the fuel, but nevertheless the source of most of the chemical energy released in combustion. Concentrated O 2 will allow combustion to proceed rapidly and energetically.

Pipes and storage vessels used to store and transmit both gaseous and will act as a fuel; and therefore the design and manufacture of O 2 systems requires special training to ensure that ignition sources are minimized. The fire that killed the crew in a launch pad test spread so rapidly because the capsule was pressurized with pure O 2 but at slightly more than atmospheric pressure, instead of the ​ 1⁄ 3 normal pressure that would be used in a mission.

Liquid oxygen spills, if allowed to soak into organic matter, such as, and can cause these materials to unpredictably on subsequent mechanical impact. These results were mostly ignored until 1860. Part of this rejection was due to the belief that atoms of one element would have no towards atoms of the same element, and part was due to apparent exceptions to Avogadro's law that were not explained until later in terms of dissociating molecules. An orbital is a concept from that models an electron as a that has a spatial distribution about an atom or molecule. Oxygen's paramagnetism can be used analytically in paramagnetic oxygen gas analysers that determine the purity of gaseous oxygen. Archived from on March 8, 2008. Retrieved December 15, 2007.

). Figures given are for values up to 50 miles (80 km) above the surface. Thylakoid membranes are part of in algae and plants while they simply are one of many membrane structures in cyanobacteria. In fact, chloroplasts are thought to have evolved from that were once symbiotic partners with the progenerators of plants and algae.

Water oxidation is catalyzed by a -containing complex known as the (OEC) or water-splitting complex found associated with the lumenal side of thylakoid membranes. Manganese is an important, and and are also required for the reaction to occur. (Raven 2005). (1.8 grams/min/person)×(60 min/h)×(24 h/day)×(365 days/year)×(6.6 billion people)/1,000,000 g/t=6.24 billion tonnes. The reason is that increasing the proportion of oxygen in the breathing gas at low pressure acts to augment the inspired O 2 partial pressure nearer to that found at sea-level. Also, since oxygen has a higher electronegativity than hydrogen, the charge difference makes it a. The interactions between the different of each molecule cause a net attraction force.

Since O 2's partial pressure is the fraction of O 2 times the total pressure, elevated partial pressures can occur either from high O 2 fraction in breathing gas or from high breathing gas pressure, or a combination of both. No single ignition source of the fire was conclusively identified, although some evidence points to an arc from an electrical spark.

Gazi rates this game: 5/5 Breath of Fire III is the third entry of the franchise and the most popular in US and EU. Its a precious homage to the good old SNES times! You'll play as young Ryu (just like in BoF I+II too, but the storys are not related except for the dragons!) who was rescued by Rei and Teepo which lives in the Cedarwoods. You'll move on and reveal several secrets about the dragon tribe and the war that leads to the extinction of those. The unique thing about BoF III is that the hero (and some of his friends) will grow up, change their appearance and personalities. This game is packed with twists, secrets, mini games and a FANTASTIC battlesystem!

If you like JRPG's this one here will BLOW YOUR MIND for sure:D. Anonymous says: This is another beautiful RPG from CAPCOM, Breath of Fire 3 has the beautiful story,interesting gameplay and nice graphics. Most interesting part of the game is that the player can choose from 16 types of gens(needs to find them first) which he can combine and depending on a combination he will turn the main character into a dragon. There are many kinds of dragons each with his own unique abilitys. As for the other character each one of them will gain new abilities as they grow in level, also all characters in the game can have masters.

Depending on their master the character will have increased STR,INT,WIS,etc. The characters can learn new abilitys from their masters, the player will find many other masters throughout the game. Also dont forget to play Breath of Fire 4 it is even better than BoF3.

Ha ha just joking both of the games are good with good stories.