How many protons, neutrons, and electrons does oxygen?
Oxygen has the symbol O and atomic number 8.It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that forms oxides with most elements as well as with other compounds.Oxygen is the third most abundant element in the universe.Dioxygen, a diatomic gas with the formula O2, is formed when two atoms of the element bind to each other.20% of the Earth's atmosphere is diatomic oxygen gas.Half of the Earth's crust is made up of oxides.[3]
Oxygen provides the energy released in combustion and aerobic cellular respiration, as well as many major classes of organic molecule in living organisms.Oxygen is the major component of water in the mass of living organisms.Oxygen is continuously regenerated in the Earth's atmosphere through the use of sunlight and carbon dioxide.Oxygen is too reactive to remain a free element in the air.The high altitude ozone layer helps protect the biosphere from ultraviolet radiation.Ozone present at the surface is a pollutant.
Oxygen was isolated by Michael Sendivogius before 1604 but it is believed that the element was discovered independently by Joseph Priestley in 1774.Priority is given to Priestley because his work was published first.Oxygen was not recognized as a chemical element by Priestley.In 1777,Antoine Lavoisier, who first recognized oxygen as a chemical element, came up with the name oxygen.
Oxygen can be used in a number of ways, including production of steel, plastics and textiles, brazing, welding and cutting, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.
One of the first known experiments on the relationship between air and gas was conducted by a Greek writer.Water rose into the neck of the vessel when it was inverted over a candle and surrounded by water.The air in the vessel was converted into classical element fire and thus was able to escape through the glass.Leonardo da Vinci was able to observe that a portion of air is consumed during combustion and respiration.[6]
Robert Boyle showed in the 17th century that air is needed for burning.John Mayow, an English chemist, refined this work by showing that fire requires only a small part of air.In one experiment, he found that placing a mouse or candle in a closed container over water caused the water to rise and replace one-fourth of the air's volume before extinguishing the subjects.He thought that nitroaereus is consumed in both respiration and combustion.
Mayow thought that the nitroaereus must have combined with antimony when it increased in weight.He 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 the substance in the body.In 1668, the accounts of these and other experiments and ideas were published in his work Tractatus duo.[8]
Oxygen was produced in experiments in the 17th and 18th century, but none of them recognized it as a chemical element.The phlogiston theory, which was the favored explanation of those processes, may have been a factor.10
The phlogiston theory states that all 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.[6]
Most of the non-combustible substances, such as iron, were thought to be made mostly of phlogiston.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.[6]
Michael Sendivogius described a substance in his work.During his experiments between 1598 and 1604 Sendivogius properly recognized that the substance is equivalent to the gaseous byproduct released by the thermal decomposition of potassium nitrate.Bugaj believes that the isolation of oxygen and the proper association of the substance to that part of air lend itself to the discovery of Oxygen.The generations of scientists and chemists which succeeded him denied the discovery of Sendivogius.[13]
Oxygen was first discovered by a Swedish pharmacist.Oxygen gas was produced by heating mercuric oxide and various nitrates.The only known agent to support combustion was the gas.He wrote about this discovery in a manuscript called Treatise on Air and Fire, which he sent to his publisher.In 1777, that document was published.[16]
On August 1, 1774, an experiment conducted by the British clergyman Joseph Priestley focused sunlight on mercuric oxide contained in a glass tube, which liberated a gas he named "dephlogisticated air".He said that candles burned brighter in the gas and that a mouse was more active and lived longer.After breathing the gas himself, Priestley 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."The second volume of his book titled Experiments and Observations on Different Kinds of Air was included in the paper "An Account of Further Discoveries in Air".Because he published his findings first, he is usually given priority in the discovery.
Lavoisier claimed to have found the new substance on his own.Lavoisier was told about his experiment by Priestley in October of 1774.Lavoisier never acknowledged receiving the letter that was sent to him on September 30, 1774, which described his discovery of the previously unknown substance.After his death, a copy of the letter was found in his belongings.)[16]
Lavoisier conducted the first proper quantitative experiments on oxidation and gave a correct explanation of how combustion works.He used these and similar experiments to disprove the phlogiston theory and prove that the substance discovered by the two men was a chemical element.
Lavoisier observed that there was no increase in weight when air and tin were heated in a closed container.When he opened the container, he saw that some of the trapped air had been consumed.The weight of the air that rushed back in was the same as the tin's weight.This was one of the experiments documented in his book.He proved that air is a mixture of two gases; 'vital air', which is essential to combustion and respiration, and azote.It did not support either.The name Azote was kept in French and several other European languages, but later became nitrogen in English.[15]
Lavoisier renamed 'vital air' to oxygne in 1777 because he mistook it for acid.Lavoisier was wrong abouthydrogen being the basis for acid chemistry, but by 1812 the name was too well established.[19]
Oxygen entered the English language despite opposition from English scientists and the fact that the Englishman who first isolated the gas wrote about it.The poem "Oxygen" in The Botanic Garden was written by the grandfather of Charles Darwin.[16]
All elements were assumed to be monatomic and the atoms in compounds would have the simplest atomic ratios with respect to one another.The conclusion was that the atomic mass of oxygen was 8 times that of hydrogen, instead of the modern value of about 16.Amedeo Avogadro arrived at the correct interpretation of water's composition based on what is now, after Joseph Louis Gay-Lussac and Alexander von Humboldt showed that water is formed of two volumes of hydrogen and one volume of oxygen.[21]
Scientists realized in the late 19th century that air could be compressed and cooled.In order to liquefy carbon dioxide, a cascade method was used by Swiss chemist and physicist Raoul Pierre Pictet.On December 22, 1877, he sent a telegram to the French Academy of Sciences in Paris to announce his discovery of liquid oxygen.Two days later, French physicist Louis Paul Cailletet announced his own method of liquefying oxygen.Only a few drops of the liquid were produced in each case.Oxygen was stable for the first time on March 29, 1884, by scientists from Jagiellonian University.[23]
James Dewar was a Scottish chemist who was able to produce liquid oxygen.The first commercially viable process for producing liquid oxygen was developed in 1895 by German and British engineers.Both men distilled component gases by boiling them off one at a time and capturing them separately, after they lowered the temperature of air.A mixture of acetylene and compressed O2 was burned for the first time in 1901.The method of welding and cutting metal became common.[25]
Robert H. Goddard was the first person to develop a rocket engine that burned liquid fuel and used gasoline and liquid oxygen as oxidizers.The rocket was flown at 97 km/h on March 16, 1926.[25][26]
Oxygen can be prepared in academic laboratories by heating a mixture of potassium chlorate and manganese dioxide.[28]
Oxygen levels in the atmosphere may be affected by fossil-fuel burning.[28]
Oxygen is a tasteless, odorless, and odorless gas at standard temperature and pressure.30
Two oxygen atoms are bound together.Depending on the level of theory, the bond can be described as a covalent double bond that results in a bond order of two.The double bond is the result of filling of the orbitals with low-to-high energy and the resulting cancellation of contributions from the 2s electrons.[29]
Dioxygen's double bond character and reactivity are affected by this combination of cancellation and.An electron configuration with two unpaired electrons is called a spin triplet state.The ground state of the O2 molecule is referred to as triplet oxygen.The filling of partially filled orbitals weakens the bond order from three to two.Because of its unpaired electrons, triplet oxygen reacts slowly with most organic molecules.[4]
O2 is paramagnetic in the triplet form.The magnetic character of oxygen is due to the spin magnetic moments of the unpaired electrons in the molecule.In laboratory demonstrations, a bridge of liquid oxygen may be supported against its own weight by a powerful magnet.[32]
Singlet oxygen is a name given to several higher-energy species of O2.It is more reactive with organic compounds than it is with triplet oxygen.Singlet oxygen is formed from water in nature.It is produced in the troposphere by the photolysis of ozone and the immune system as a source of active oxygen.Carotenoids play a major role in absorbing energy from singlet oxygen and converting it to the unexcited ground state before it can cause harm to tissues.36
Dioxygen, O2, is the major part of the Earth's atmospheric oxygen.The exothermic reaction of O2 with any organic molecule is responsible for the bond energy of 498 kJ/mol, which is smaller than other double bonds or pairs of single bonds in the biosphere.O2 is used by complex forms of life, such as animals, in cellular respiration.Other aspects of O2 are covered in the rest of the article.
ozone is a very reactive allotrope of oxygen that is damaging to lung tissue.Ozone is produced in the upper atmosphere when O2 is combined with atomic oxygen.The ozone layer of the upper atmosphere is a protective radiation shield for the planet.Near the Earth's surface, it is a pollutant formed as a result of automobile exhaust.A sufficient amount of atomic oxygen is present at low altitudes.40
The metastable molecule was discovered in 2001 and was assumed to exist in one of the six phases of solid oxygen.The phase created by pressurizing O2 to 20 GPa is a rhombohedral O8 cluster.This cluster has the potential to be a much more powerful oxidizer than either O2 or O3 and may be used in rocket fuel.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 superconducting.[45]
Oxygen can be dissolved more readily in water than in nitrogen.Water in equilibrium with air contains 1 molecule of dissolved O2 for every 2 molecules of N2 compared with an atmospheric ratio of 1:4.Oxygen dissolved at 0 C is twice as much as at 20.At 25 C and 1 standard atmosphere (101.3 kPa) of air, freshwater contains about 6.04 liters of oxygen per liter.The amount of water and sea water in a liter increases by 50% and 45%, respectively, at 5 C.
Oxygen condenses at 90.20 K and freezes at 54.36 K.In contrast to the blue color of the sky, both liquid and solid O2 have a light sky-blue color due to absorption in the red.The high-purity liquid O2 can be obtained by fractional distillation.Liquid oxygen may be used as a coolant.50
The atmospheric processes of airglow and the Aurora are associated with the analysis of molecular oxygen.The Herzberg continuum and Schumann–Runge bands produce atomic oxygen that is important in the chemistry of the middle atmosphere.Red Chemiluminescence is caused by excited state singlet molecular oxygen.[52]
The most abundant stable isotopes in naturally occurring oxygen are 16O, 17O and 18O.[54]
Most 16O is synthesised at the end of the fusion process in massive stars, but some is made in the neon burning process.17O is found in the hydrogen burning zones of stars due to the burning of hydrogen into helium during the CNO cycle.Most 18O is produced when 14N (made abundant from CNO burning) captures a 4He nucleus.[55]
Fourteen radioisotopes have been characterized.The most stable are 14O with a half-life of 70.606 seconds.The majority of the remaining radioactive isotopes have half-lives that are less than 83 milliseconds.The most common decay mode of the heavier isotopes is + decay to yield nitrogen.[54]
Oxygen is the most abundant chemical element in the Earth.Oxygen is the third most abundant chemical element in the universe.Oxygen is a small part of the Sun's mass.Oxygen is the most abundant element by mass in the Earth's crust and is part of oxide compounds.It is the largest component of the world's oceans.Oxygen gas is the second most common component of the Earth's atmosphere, taking up 28.3% of its volume and 23.0% of it' s mass.Earth has a high concentration of oxygen gas in its atmosphere, which is unusual among the planets of the Solar System.The O2 surrounding those planets is produced by the action of ultraviolet radiation.
The oxygen cycle causes the high concentration of oxygen gas on Earth.The biogeochemical cycle describes the movement of oxygen between the atmosphere, the biosphere, and the lithoosphere.The main driver of the oxygen cycle is photosynthesis.Oxygen is released into the atmosphere by photosynthesis, while other processes remove it.Production and consumption occur at the same rate.[63]
The world's water bodies have free oxygen in them.As polar oceans support a higher density of life due to their higher oxygen content, the increased solubility of O2 at lower temperatures has important implications for ocean life.Eutrophication and the decay of organisms and other biomaterials may reduce the O2 content in water bodies.The amount of O2 needed to restore the water to a normal concentration is assessed by scientists.[65]
The climate millions of years ago was determined by the ratio of oxygen-18 and oxygen-16 in the shells and skeletons of marine organisms.The difference in the rate of evaporate between water and water with heavier oxygen-18 increases at lower temperatures.During periods of lower global temperatures, snow and rain from that evaporated water tends to be higher in oxygen-16.In a warmer climate, marine organisms use less oxygen-18 into their skeletons and shells.Paleoclimatologists measure this ratio in the water of ice core samples as old as hundreds of thousands of years.
The relative quantities of oxygen in samples from the Earth, the Moon, Mars, and meteorites have been measured, but can't be compared to the ratios in the Sun.The Sun has a higher proportion of oxygen-16 than the Earth, according to analysis of a Silicon wafer exposed to the solar wind in space.An unknown process depletes oxygen-16 from the Sun's disk of protoplanetary material prior to the coalescence of dust grains that formed the Earth, according to a measurement.[67]
There are two absorption bands at the 687 and 760 nm wavelength.The measurement of the radiance coming from vegetation canopies in those bands could be used to determine plant health status from a satellite platform.This approach exploits the fact that in those bands it is possible to discriminate the vegetation's reflectance from its fluorescence, which is much weaker.The measurement is technically difficult due to the low signal-to-noise ratio and the physical structure of vegetation, but it has been proposed as a possible method of monitoring the carbon cycle from satellites on a global scale.
In nature, free oxygen is produced by the splitting of water.According to some estimates, green algae and cyanobacteria in marine environments provide 70% of the free oxygen produced on Earth.Estimates of the ocean's contribution to atmospheric oxygen are higher than those that are lower.70
The energy of four photons is required for photolytic oxygen evolution.Many steps are involved, but the result is the formation of a proton gradient across the thylakoid membrane, which is used to synthesise adenosine triphosphate via photophosphorylation.After production of the water molecule, the remaining O2 is released into the atmosphere.F
The chemical energy of oxygen is released in the body.The reaction for aerobic respiration is similar to the reverse of photosynthesis.
O2 enters red blood cells through the lungs.Hemoglobin binding O2 causes it to change color from bluish red to bright red.Hemocyanin and hemerythrin are used by other animals.200 cm3 of O2 can be dissolved by a liter of blood.[62]
Oxygen was thought to be a requirement for all life until the discovery of metazoa.[74]
Oxygen use in organisms can cause reactive oxygen species, such as superoxide ion and hydrogen peroxide.peroxide, superoxide, and singlet oxygen are created by parts of the immune system of higher organisms.Plants have a hypersensitive response to pathogen attack.Oxygen is damaging to obligately anaerobic organisms, which were the dominant form of early life on Earth until O2 began to accumulate in the atmosphere about a billion years after the first appearance of these organisms.There are 75 and 76 words.
A human at rest inhales up to 2.4 grams of oxygen per minute.The amount of oxygen exhaled by humans per year is more than 6 billion.[g]
The respiratory system has the highest free oxygen partial pressure in the body of a living animal.If oxygen alone occupied the volume, partial pressure would be the pressure.81
About 3.5 billion years ago, free oxygen gas was almost completely absent in Earth's atmosphere.Between 3.0 and 2.3 billion years ago, free oxygen appeared in significant quantities.Even if there was a lot of dissolved iron in the ocean, the banded iron formations were created by iron-oxidizingbacteria which dominated the deeper areas of the photic zone.Around 1.7 billion years ago, free oxygen began to outgas from the oceans, reaching 10% of its present level.[84]
A large amount of dissolved and free oxygen in the ocean and atmosphere may have led to the extinction of most of the ancient organisms.O2 allows aerobic organisms to produce moreATP than anaerobic organisms.Cellular respiration of O2 occurs in all organisms, including plants and animals.
Since the beginning of the Cambrian period 540 million years ago, atmospheric O2 levels have fluctuated between 15% and 30% by volume.At the end of the Carboniferous period, atmospheric O2 levels reached a maximum of 35% by volume, which may have contributed to the large size of insects and salamanders.[87]
Past climates have been shaped by variations in atmospheric oxygen concentration.When oxygen declined, atmospheric density dropped, which in turn increased surface evaporation, causing precipitation increases and warmer temperatures.[88]
It would take about 2,000 years for the entire O2 to be regenerated.[89]
Oxygen is a strong biosignature in the search for extraterrestrial life.It might not be a definite biosignature, being possibly produced abiotically on heavenly bodies with processes and conditions which allow free oxygen.93
One hundred million tonnes of O2 are taken from the air each year.The most common method is fractional distillation of the air, where N2 is left as a liquid while O2 becomes a vapor.[16]
The main method of producing O2 is passing a stream of clean, dry air through one bed of a pair of identical zeolite molecular sieves, which absorb the nitrogen and deliver a gas stream that is 90 to 98% O2.In the reverse direction of flow, nitrogen gas is released from the other nitrogen-saturated zeolite bed by reducing the chamber's operating pressure.After a set cycle time, the operation of the two beds is interchanged so that a continuous supply of oxygen can be pumped through a pipe.This is called pressure swing adsorption.Oxygen gas can be obtained by these non-cryogenic technologies.[94]
Water can be used to make hydrogen and oxygen.If AC is used, the gases in each limb have a 2:1 ratio of hydrogen and oxygen.The O2 evolution from oxides and oxoacids is a similar method.In case of depressurization emergencies, chemical catalysts can be used on commercial airliners, as well as in chemical oxygen generators or oxygen candles that are used as part of the life-support equipment on submarines.Another method of air separation is by forcing air to be dissolved through a ceramic membranes, using either high pressure or an electric current.[65]
High pressure oxygen tanks are one of the methods of oxygen storage.Oxygen is often transported in bulk as a liquid in specially insulated tankers, since it is equivalent to over 800 liters of gaseous oxygen at atmospheric pressure and 20 C.Tanks 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 heat exchanger before entering the building.Oxygen can be stored and shipped in smaller cylinders containing compressed gas, which is useful in portable medical applications and oxy-fuel welding and cutting.[16]
Oxygen is used in medicine to increase uptake of O2 from the air.Treatment increases oxygen levels in the patient's blood, but also decreases resistance to blood flow in many types of diseased lungs, easing work load on the heart.Oxygen therapy can be used to treat diseases such as emphysema, pneumonia, some heart disorders, and disorders that cause increased pulmonary artery pressure.95
Treatments can be used in hospitals, the patient's home, or by portable devices.Oxygen tents have been replaced mostly by the use of oxygen masks or nasal cannulas.[98]
Hyperbaric medicine uses special oxygen chambers to increase the partial pressure of O2 around the patient and the medical staff.Sometimes carbon monoxide poisoning, gas gangrene, and decompression sickness can be addressed with this therapy.Increased O2 concentration in the lungs helps to remove carbon monoxide from the heme group of hemoglobin.Oxygen gas is poisonous to the anaerobicbacteria that cause gas gangrene, so increasing its partial pressure helps kill them.Decompression sickness is caused by 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 O2 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.Normobaric oxygen administration at the highest concentration is often used as the first aid for diving injuries that may involve gas bubble formation in the tissues.A statistical study of cases recorded in a long term database supports its use.There are 105 and 106 words.
Modern space suits surround their occupant's body with breathing gas when O2 is applied.A normal blood partial pressure of O2 is created when these devices use nearly pure oxygen.Maintaining suit flexibility requires a trade-off of higher oxygen concentration for lower pressure.It was108 and109.
Artificially delivered O2 is used by scuba and surface-supplied underwater divers and submariners.Submarines, submersibles and atmospheric diving suits operate at normal atmospheric pressure.Oxygen and carbon dioxide are removed from the air to maintain a constant partial pressure.Ambient pressure divers breathe in air or gas with an oxygen fraction suited to the operating depth.Pure or nearly pure O2 use in diving at pressures higher than atmospheric is usually limited to rebreathers or medical treatment in recompression chambers.Oxygen toxicity can be prevented by significant dilution of O2 with other gases.[115]
People who climb mountains or fly in non-pressurized fixed-wing aircraft may have supplemental O2 supplies.In case of cabin depressurization, an emergency supply of O2 is automatically supplied to the passengers.Oxygen masks can be dropped due to sudden cabin pressure loss.Pulling on the masks "to start the flow of oxygen" as cabin safety instructions dictate, forces iron filings into the sodium chlorate inside the canister.A steady stream of oxygen gas is produced.
Oxygen has a history of recreational use in bars and sports.Oxygen bars are establishments that offer higher than normal O2 exposure for a minimal fee.Oxygen masks are used by professional athletes in American football to boost performance.The placebo effect is a more likely explanation.If you breathe in oxygen enriched mixtures during aerobic exercise, there is a performance boost.[113]
George Goble's five-second ignition of barbecue grills is one of the recreational uses that do not involve breathing.[ 114]
Half of the commercially produced oxygen is consumed by the melting of iron Ore into steel.In this process, O2 is injected through a high-pressure lance into molten iron, which removes sulfur impurities and excess carbon as the respective oxides, SO2 and CO2.The temperature increases to 1,700 C when the reactions are exothermic.[65]
The chemical industry uses 25% of the commercially produced oxygen.Ethylene is reacted with O2 to create ethylene oxide, which in turn is converted into ethylene glycol, the primary material used to manufacture a host of products.Large quantities of oxygen or air are used in oxy-cracking process and in the production of diformyl-furane and benzylic acid.The synthesis of hydrogen peroxide from oxygen is a promising technology to replace the currently used hydroquinone-process.In afterburners, catalytic oxidation is used to get rid of hazardous gases.[118]
Oxygen is used in medical applications, metal cutting and welding, as an oxidizer in rocket fuel, and in water treatment.oxyacetylene welding uses oxygen and O2 to produce a very hot flame.The metal is heated with a small acetylene flame and then cut by a large stream of O2.[118]
Oxygen has an oxidation state of 2 in most compounds.The oxidation state is found in some compounds.The compounds containing oxygen in other oxidation states are very rare.[123]
Water is a compound of hydrogen and oxygen.The attraction of hydrogen atoms to an adjacent oxygen atom in a separate molecule is about 23.3 kJ/mol per hydrogen atom.The hydrogen bonds between water molecule hold them close to what would be expected in a simple liquid with just van der Waals forces.[125]
Oxygen forms chemical bonds with other elements to give oxides.The surface of most metals, such as titanium and aluminum, oxidizes in the presence of air and are coated with a thin film of oxide that passes through the metal and slows further oxidation.Many oxides of the transition metals are non-stoichiometric compounds.The mineral FeO is written as Fe 1 x O, where x is usually around 0.05.126
Carbon dioxide is present in trace quantities in the atmosphere.The Earth's crustal rock is made up of large parts of oxides of Silicon, Al2O3 and iron.Oxygen compounds are found in the rest of the Earth's crust.The Earth's mantle is composed of magnesium and iron.
detergents and glues are made from water-soluble silicates.There are 127 words.
Transition metal dioxygen complexes feature metal–O2.hemoglobin and myoglobin are included in this class of compounds.An exotic and unusual reaction occurs with PtF6, which oxidizes oxygen.[129]
Among the most important classes of organic compounds are alcohols, ethers and aldehydes.There are many important organic solvents that contain oxygen.In the synthesis of many different substances, acetone and phenol are used.acetic anhydride and acetamide are important organic compounds that contain oxygen.The oxygen atom is part of a ring of three atoms in ethers.The element is found in almost all biomolecules that are important to life.
Oxygen reacts with many organic compounds at or below room temperature in a process called autoxidation.Most of the organic compounds that contain oxygen are not made by O2.ethylene oxide and peracetic acid are organic compounds that are important in industry and commerce.There are 127 words.
The standard rates compressed oxygen gas as nonhazardous to health, nonflammable and nonreactive, but an oxidizer.All other ratings are the same as the compressed gas form and the health hazard rating for refrigerated liquid oxygen is 3.[131]
Oxygen gas can be toxic at elevated partial pressures, leading to convulsions and other health problems.Oxygen toxicity usually begins to occur at partial pressures more than 50 kPa, equal to about 50% oxygen composition at standard pressure or 2.5 times the normal sea-level O2 partial pressure.This is not a problem for patients on mechanical ventilators, since the gas supplied through oxygen masks in medical applications is typically composed of less than 50% O2 by volume.[9]
Premature babies used to be placed in incubators with O2 rich air, but this practice was stopped after some babies were blinded by the high oxygen content.[9]