what is critical oxygen tension?
374899
Here you go:\n\n"Critical oxygen tension is the minimum amount of dissolved oxygen necessary to sustain metabolic processes."\n\nCheers!
904142
The amount of oxygen dissolved in water is measured in mg O2/liter of water and varies with temperature and atmospheric pressure at the surface. It can be anywhere from 5-12 (approximately) mg/liter.
880533
Alex is right, but what you mean is oxygen saturation of the blood.  This tells you how much oxygen is saturated in the hemoglobin of the blood to transport through the body.  Ideal, like Alex said is 95%-100%.
406844
Medical oxygen probably has to be USP (United States Pharmacoepia) grade, which means there's a long list of things it can't contain.  It might also have to be dry, but I'm not sure on that one.
455306
Oxygen, like a lot of substances our body needs, can be harmful in large quantities.  This is partly due to its highly electromagnetic and hydrophyllic nature.  As any patient that has been on oxygen therapy can tell you, your body is "set" to use a certain percentage of oxygen in the air we breathe.  If we get used to a higher amount, and then this amount is depreived, we feel light-headed and weak.  This is because at higher levels of oxygen, our lungs become accustomed to a smaller amount of effort to extract and use the oxygen from the air.  \n\nOxygen's corrosive nature is not found in the O2 form however, but the O and O3 (ozone) forms.  This is because oxygen is most stable in the O2 form.  This is where oxygen "wants" to be.  The O3 and O forms are unstable, and prone to reactions.    \n\n"Oxygen can be toxic at elevated partial pressures (i.e. high relative concentrations). This is important in some forms of scuba diving, such as with a rebreather.\n\nCertain derivatives of oxygen, such as ozone (O3), singlet oxygen, hydrogen peroxide, hydroxyl radicals and superoxide, are also highly toxic. The body has developed mechanisms to protect against these toxic compounds. For instance, the naturally-occurring glutathione can act as an antioxidant, as can bilirubin which is normally a breakdown product of hemoglobin. To protect against the destructive nature of peroxides, nearly every organism on earth has developed some form of the enzyme catalase, which very quickly disproportionates peroxide into water and dioxygen.\n\nHighly concentrated sources of oxygen promote rapid combustion and therefore are fire and explosion hazards in the presence of fuels. The fire that killed the Apollo 1 crew on a test launchpad spread so rapidly because the capsule was pressurized with pure oxygen as would be usual in an actual flight, but to maintain positive pressure in the capsule, this was at slightly more than atmospheric pressure instead of the 1/3 pressure that would be used in flight. (See partial pressure.) Similar hazards also apply to compounds of oxygen with a high oxidative potential, such as chlorates, perchlorates, and dichromates; they also can often cause chemical burns.\n\nOxygen derivatives are prone to form free radicals, especially in metabolic processes. Because they can cause severe damage to cells and their DNA, they form part of theories of carcinogenesis and aging." (Wikipedia 2006)\n\n"Oxygen is the most abundant element on this planet. The earth's crust is 46.6% oxygen by weight, the oceans are 86% oxygen by weight, and the atmosphere is 21% oxygen by volume. The name oxygen comes from the Greek stems oxys, "acid," and gennan, "to form or generate." Thus, oxygen literally means "acid former." This name was introduced by Lavoisier, who noticed that compounds rich in oxygen, such as SO2 and P4O10, dissolve in water to give acids.\n\n"Fluorine is the only element that is more electronegative than oxygen. As a result, oxygen gains electrons in virtually all its chemical reactions. Each O2 molecule must gain four electrons to satisfy the octets of the two oxygen atoms." ("Chemistry of Oxygen" - Bodner Research Group)
497010
DUE TO SURFACE TENSION POSITIVE ANGLE OF CONTACT AND INTERNAL PRESSURE.
699839
carries oxygen around the body
827670
Decrease because there is less oxygen. I think.
484467
Under 1 atm of pressure,\n-The melting point / freezing point of Oxygen gas is: 54.8 Kelvin.\n-The boiling point of Oxygen gas is: 90.2 Kelvin.\n\nOxygen gas would be a liquid (under 1 atm) anywhere between 54.8 and 90.2 Kelvin (-218.3 degrees C and -182.9 degrees C).
559340
The boiling point of oxygen is -183°C, or 90°K (-297°F).\n\nThe melting point of oxygen is -218.4°C, or 54.8°K  (-361.1°F)
136486
Oxygen is the only gas we really need to breathe in order to stay alive. If we don't breathe oxygen (or if we don't breathe enough oxygen), we soon die. Interestingly enough, too much oxygen can be a bad thing also. At right is a diagram illustrating the range of oxygen concentrations that we can breathe safely. The green and red bar represents a scale of inspired oxygen partial pressures (PO2), ranging from zero oxygen on the left, to a PO2 of 2.0 ATA on the right. Through evolution, our bodies have become optimized to breathe oxygen at a partial pressure (PO2) of 0.21 ATA. If the inspired PO2 is much less than this, our bodies begin to shut down -- leading to unconsciousness when the PO2 drops below about 0.1 ATA (i.e., 10% oxygen at sea level). This is called hypoxia. Breathing more than 0.21 ATA oxygen is generally fine ... up to a point. If the inspired PO2 is maintained above about 0.5 ATA for prolonged periods of time (many hours to days), people begin to suffer what is usually referred to as "pulmonary" or "chronic" oxygen toxicity. The effects of this include a burning sensation or irritation in the lungs, and can affect breathing. Except for people who spend days under pressure at a time (e.g., commercial divers on oil rigs), this form of oxygen toxicity is not much of a problem for divers.\n\nHowever, as the inspired PO2 starts to climb above about 1.2 to 1.4 ATA, another kind of oxygen toxicity, called "CNS" (for "Central Nervous System") or "acute" oxygen toxicity, becomes a significant problem. Although a variety of subtle symptoms such as muscular twitching in the face and tunnel vision have been attributed to this kind of oxygen toxicity, the really important symptom is severe, uncontrolled convulsions. Although these convulsions do not appear to cause any sort of permanent damage by themselves, the problem of a diver experiencing such convulsions being able continue to hold a regulator in his or her mouth is obvious. More than a few divers have drowned underwater, apparently a result of oxygen-induced convulsions. This is perhaps the most serious and insidious of diving maladies, because it comes on unpredictably and without warning, and usually results in the death of the afflicted diver.\n\nThere is no clear understanding on the exact biochemical processes involved with CNS oxygen toxicity, nor is there a clear consensus on what the "safe" upper PO2 limit should be. Convulsions have occurred in divers breathing an inspired PO2 as low as 1.2 ATA, but such cases usually involve extenuating circumstances (such as medical conditions in the divers which pre-dispose them to convulsions). Conversely, commercial divers in Europe have routinely breathed oxygen partial pressures as high as 1.9 ATA in the water, and hyperbaric chamber facilities regularly expose patients to 2.8 ATA of oxygen (or more) without difficulty. Amid the ambiguities, two trends seem very consistent. The first is that high levels of exercise (perhaps more specifically, high levels of CO2 in the blood) appear to increase the probability of suffering from a convulsion. Secondly, divers immersed in water have a lower tolerance to elevated concentrations of inspired oxygen than do divers kept dry in a hyperbaric chamber or undersea habitat. (this over and above the fact that divers in a dry habitat are much more likely to survive a convulsion than are divers immersed in water). Another unavoidable reality regarding oxygen toxicity is the extreme range of variation both between individuals, and within a single individual.\n\nWhen immersed underwater, most divers regard a PO2 of 1.4 ATA as a safe upper limit during periods of physical exertion, and 1.6 ATA during periods of rest.
407921
http://en.wikipedia.org/wiki/Oxygen_debt
308472
Find yourself a z-statistic table and look up critical value in the table.  Check your stats book on how to interpret the table.\nhttp://www.math2.org/math/stat/distributions/z-dist.htm
786932
Boiling point is the temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure.  Raising the temperature of a liquid increases the vapor pressure.  The higher the vapor pressure of a liquid already is, the lower the temperature required for it to boil.  Oxygen has a lower boiling point than hydrogen because it has a higher vapor pressure.  The reason for this is because there are less intermolecular forces holding oxygen together than there are intermolecular forces holding together hydrogen chloride.  In oxygen, there are weak London forces and nonpolar-covalent bonds.  In hydrogen chloride, there are London forces AND a polar-covalent bond.
390741
Your depth of breathing and rate of breathing is adjusted by your body to keep your arterial blood oxygen saturation level about 95+% (this can be checked with a simple oximeter) and the arterial carbon dioxide at 40 mm Hg (this usually requires an arterial blood sample to check).
1163335
Wrong. There is the critical temperature/pressure up to which gas and liquid behave differently. Above these conditions, there cannot exist a liquid phase. Rather than speaking about gaseous phase, this state is called fluid. This state is also called supra-critical.\n\nBasically what happens is that the attractive forces in the liquid diminish as the critical point is approached, until the liquid behaves just like the vapour. The evaporation heat becomes zero.
380084
The answer is Pressure\n\n10 pts plz! im only level 1!