What is Oxygen: Definition and 374 Discussions

Oxygen is the chemical element with 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 readily forms oxides with most elements as well as with other compounds. After hydrogen and helium, oxygen is the third-most abundant element in the universe by mass. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.Dioxygen provides the energy released in combustion and aerobic cellular respiration, and many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as do the major constituent inorganic compounds 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 in Earth's atmosphere by photosynthesis, 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 (allotrope) of oxygen, ozone (O3), strongly absorbs ultraviolet UVB radiation and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. However, ozone present at the surface is a byproduct of smog and thus a pollutant.
Oxygen was isolated by Michael Sendivogius before 1604, but it is commonly believed that the element was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774. Priority is often given for Priestley because his work was published first. Priestley, however, called oxygen "dephlogisticated air", and did not recognize it as a chemical element. The name oxygen was coined in 1777 by Antoine Lavoisier, who first recognized oxygen as a chemical element and correctly characterized the role it plays in combustion.
Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.

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  1. emilmammadzada

    Atomic density of Oxygen in a composite

    Dear experts, how can I calculate the atomic density of Oxygen in a composite of 05 percent PuO2 and 95 percent UO2 (in atoms/barn-cm)? (5% U235 enriched)
  2. G

    Calculating atmospheric partial pressure of oxygen

    I study genotype-environment associations in alpine species. I frequently see altitude as the sole predictor of partial pressure of oxygen in the literature concerning hypoxia adaptations. However, I understand that partial pressure of oxygen is also influenced by temperature, humidity, and...
  3. martijn_tholen

    Propane/Oxygen - from Cylinder to Oxy/Fuel cutting torch

    For one of our projects we are at present using quite large amounts of gas & oxygen. What I was trying to figure out was how to calculate the total available amount of gas in a cylinder (be that either Propane/Oxygen or Propylene (Propene)) and then to determine whether or not -given a certain...
  4. Frankenstein19

    Will dissolved oxygen increase in a water sample inside a jar?

    If I have 100mL inside a glass with a closed cap. I take the cap off, measure DO, put the cap back on and decrease the temperature 20 degrees. No agitation of any sort. Does the DO increase?
  5. Astronuc

    B Sun contains more oxygen, silicon and neon than previously thought

    Ekaterina Magg, Maria Bergemann and colleagues have published results of new calculations concerning the composition of the sun. https://phys.org/news/2022-05-solar-spectrum-decade-long-controversy-sun.html As part of the work on her Ph.D. in that group, Ekaterina Magg set out to calculate in...
  6. BenDover

    Why does combining Hydrogen, Oxygen and Sulphur produce a liquid?

    Hydrogen is a gas, sulfur is a solid, oxygen is a gas, why does combining them to produce sulfuric acid produce a liquid?
  7. BenDover

    Oxygen gas produced by a Solid element + sodium hydroxide solution?

    Hello. I am wondering; which solid at room temperature elements produce oxygen gas when put into a solution of sodium hydroxide? Thanks
  8. C

    Videos of exploding oxygen tanks

    I can't find anywhere direct videos of exploding oxygen tanks. Have you seen one? How does it explode? Does the tank disintegrates into smithereens like a sidewinder missile? Or does the cap blows off and the oxygen tanks becoming projectiles? And how do the exploding flames behave? The tank...
  9. C

    Oxygen Tank -- What if the person's flow rate is too high? (2l/min. vs 4l/min.)

    Covid is surging again due to the Delta Variant. I saw in the news of many oxygen tanks with people connected to them even outside in hospital tents. I'd like to know something. If a person accidentally given more oxygen than required, for example. 4 Liter/Minute instead of 2 Liter/Minute...
  10. T

    Oxygen Extracted from Martian Atmosphere - a first

    On April 20, 2021, an experiment on the NASA Perseverance Mars Rover broke down the CO2 Mars atmosphere to 2CO + O2. That makes it the first instrument to produce Oxygen on another world. Still a ways to go, design maximum is 10 grams per hour, people need around 60 grams per hour...
  11. PainterGuy

    Production of oxygen in a submarine

    Hi, I was watching the following video. Around 17:00 the following is said: I tried to balance the chemical equation as presented in the video. Please have a look below. I don't see how the production of iron oxide yields more oxygen in the entire reaction. The heating of sodium chlorate...
  12. jim mcnamara

    Far IR emitting fabrics increase transcutaneous oxygen levels

    "Randomized Controlled Trial Comparing the Effects of Far-Infrared Emitting Ceramic Fabric Shirts and Control Polyester Shirts on Transcutaneous PO2" K Washington et al 2018 Apr 10. doi: 10.4172/2165-8064.1000349 J Text Sci Eng. 2018; 8(2): 349. This study affirmed the fabric's effect -...
  13. F

    Calculating Flow rate for an oxygen system

    I'm struggling with calculating the flow rate for an oxygen system. There is a pressurised cylinder. This then joins onto a pressure reducer. Then travels down a length of pipe which branches off to 4 exits there is no restrictions on the exits it just goes to atmospheric pressure. I am yet to...
  14. Epsilon Eridani

    Turning oxygen into fluorine in our atmosphere

    Summary:: Hypothetical discussion of a method to turn oxygen into fluorine through the use of another chemical and also discussing the biological effects of fluorine. Hello, I'd like to start this by saying my knowledge of chemistry is extremely basic. I barely graduated chemistry in high...
  15. S

    Partial pressure of oxygen at a certain altitude

    The pressure of oxygen at sea level = ##\frac{20.9}{100} ~\text{x} ~(21.2 ~\text{x} ~ 10^3) = 4430.8~ \text{Pa}## Then I do not know how to calculate the pressure at altitude 7000 m. I tried using P = ρgh (taking ρ as density of air = 1.3 kg/m3) then subtract the result from 4430.8 Pa but got...
  16. M

    What does HC3 mean in 'His HC3'?

    My lecturer said it means: "3rd residue, C-terminal to Helix 'H'" but that makes no sense. If it's the 3rd residue then it can't be on the C-terminal, because the C-terminal is at the end of a massively long sequence of residues. Visa versa if it's on the C-terminal then it can't be the 3rd...
  17. J

    I Bose Einstein Condensate For Oxygen 16 and Oxygen 18

    I am interested in whether or not Bose Einstein condensates have been realized for spin zero stable oxygen isotopes and if so, the maximum density achieved for these condensates. I understand that the quantum spins of oxygen 16 and oxygen 18 are both zero so such condensates would seem to be...
  18. A

    Understanding Radio Waves & Oxygen Absorption at 60GHz

    Homework Statement: I am having difficulty understanding what exactly is happening when radio transmissions are being absorbed by oxygen at 60GHz at the atomic level. Homework Equations: Refraction/reflection, oxygen absorptions/attenuation, frequency I have tried to find the answers online...
  19. Ygggdrasil

    2019 Nobel Prize in Physiology or Medicine

    Today, the 2019 Nobel Prize in Physiology or Medicine was awarded to three scientists who study how cells sense and respond to changes in oxygen levels: https://www.nobelprize.org/prizes/medicine/ These three scientists were previously awarded the Lasker Prize for Basic Medical Research in...
  20. Z

    Negative Charge Stability: Oxygen vs. Carbon/Nitrogen

    Why is it that it is more stable for a negative charge to be spread over 2 oxygens than one oxygen and 3 carbon atoms? Following that logic, why is it more stable to spread a negative charge over 3 oxygen atoms than over 1 oxygen atom and one nitrogen atom? Is it because the difference in...
  21. P

    B Oxygen Transformation: A Puzzling Phenomenon

    Hi, guys. Just found a missing thing in my brain: if atomic oxygen will meet free electron somewhere why doesn't it become fluorine or even argone?
  22. M

    Understanding Polyatomic Ion Charges and Number of Oxygen

    I have recently started self studying chemistry and I am at the point where I'm learning to name chemicals given chemical formulas and vice versa. (Like Iron (III) Oxide --> Fe2O3). I am having trouble with doing this process for polyatomic ionic compounds. I can't seem to remember some the...
  23. C

    Oxygen + neutron = nitrogen ?

    I don't understand this line in iter website. How is this reaction possible? "When exposed to the intense flux of neutrons from the fusion reaction, the oxygen present in the water generates short-lived radioactive isotopes of nitrogen—one (isotope 16) emitting a highly energetic gamma ray, the...
  24. D

    Why is enthelpy of combustion 0Kjmol-1 for oxygen

    Homework Statement Why is enthalpy of combustion 0KJmol-1 for oxygen? I need to know this for my exam coming up soon. Homework Equations The enthalpy change when 1 mole of a substance is burnt in excess oxygen under standard states under standard conditions. The Attempt at a Solution Oxygen...
  25. N

    What would happen if ozone, nitrogen and oxygen disappear?

    Hi everyone! I have some trouble figuring out the following question: If oxygen, nitrogen and ozone did not absorb UV radiation, what would you expect the temperature profile in the atmosphere to look like between the surface and top of the atmosphere? Specify the temperatures at Tropopause...
  26. KF81

    Is Oxygen Used for More Than Just Respiration in the Body?

    Hiya.. I know we need Oxygen to remove Electrons from the end of the ATP Cycle in Mitochondria but do we use Oxygen for anything else in the body ? Cheers
  27. F

    Pressure drop / dissolved oxygen

    Hello Everyone, I've been trying to find an answer to this but am not getting anywhere. Any help would be greatly appreciated! I need to be able to calculate (or more likely estimate) the pressure drop I can expect when putting water under pressure if I know there is air in the system. For...
  28. Navin

    Difference between Oxygen Tension and Partial Pressure

    Homework Statement What's the difference between Oxygen Tension And Partial Pressure Homework Equations ...uh...rules of grammar ? The Attempt at a Solution If I knew the solution I wouldn't be here now would I ? Here are a few links https://en.m.wikipedia.org/wiki/Blood_gas_tension...
  29. M

    Thermodynamics question: venting a tank of liquid oxygen

    I am trying to figure out how you can subcool a dewar of liquid oxygen (vacuum insulated) just by releasing the pressure sitting on top of it. The liquid I am thinking of in this case is liquid oxygen, which boils at -297.33 F at 1 atm. Let's say I fill a dewar with LO2, then pressurize that...
  30. Morlaf

    Stargazing Why is Oxygen so abundant?

    Basically H is most abundant obviously... He is next, also obvious... Why is oxygen the next most abundant element? and by the way... I am a big boy I can handle answers of the sort: "Because that is just how it is..." but any more scientific insight is more than welcome! Thanks, Morlaf
  31. D

    BOD (biochemical oxygen demand) calculation

    Homework Statement A seeded BOD test is to be conducted on meat-processing wastewater with an estimated strength of 800 mg/L. The seed is supernatant from aged, settled, domestic wastewater with BOD of about 150 mg/L. Calculate the BOD value for the industrial wastewater if the initial DO in...
  32. Space_Girl

    B Life Outside Our Planet Without Oxygen and Water

    Hello everyone :) I have a question.Is it possible for life to exist in other planets without oxygen and water? I mean just because we need it to survive here on Earth.It doesn’t mean all planets need it to support life as well.
  33. M

    Can you separate hydrogen and oxygen molecules?

    Is separating hydrogen and oxygen molecules possible? If so, how?
  34. M

    What happens if you add oxygen to water lacking oxygen?

    Does adding oxygen influence any physical properties of water which is oxygen deficient? Is it possible that adding oxygen leads to some temperature change and expansion?
  35. M

    Is water at the bottom of the ocean oxygen deficient?

    Is water at the bottom of the ocean oxygen deficient? Compared to water at the higher levels.
  36. wolram

    When did hydrogen combine with oxygen

    This maybe a silly question but I do not know the answer. Did hydrogen combine with oxygen to form water in geological times or did they combine before that
  37. M

    Energy diagram for hybridized oxygen in CO

    Homework Statement Please look at the screenshot attached. The answer is "Yes", but I am not sure why. Homework Equations N/A The Attempt at a Solution Oxygen have six electrons, but the energy diagram shows only five. That was why I thought it was wrong, but the diagram shown is correct...
  38. I

    Why is there a negative charge on the oxygen atom with the single bond?

    My question is that why is the negative charge on the oxygen atom with the single bond, why not on the oxygen atom with the double bond? I am confused. Source: https://chem-net.blogspot.in/2012/01/simple-procedure-for-writing-lewis.html
  39. menniandscience

    Seeds Need Oxygen Before Growing - Why?

    hi anyone and everyone! why do seeds need oxygen before they grow, in the time they are waiting for the right conditions to grow thanks
  40. T

    Pressure caused by beam of molecular oxygen

    Homework Statement A beam of molecular oxygen containing 1010 molecules/cm3 and average speed of 500 m/s strikes (elastic collision) a plate at an angle of 30º with the normal direction. Calculate the exerted pressure on the plate. Homework Equations P = Impluse x Flux The Attempt at a...
  41. J

    A Oxygen 760nm spectroscopy - quick 'n' dirty

    'Morning all, I wish to use a 760nm laser to measure the concentration of molecular oxygen in a gas. I've a laser (multi-mode, not TDLAS:QLD-760-10S), a photodiode (Si), and I've built an oven to hold the laser diode at a constant temperature to avoid mode-hopping. Is it really as 'simple' as...
  42. F

    Removing Dissolved Oxygen from Water

    Hello, I am working with an artist to build enclosures that would hold magnetite sculptures in water filled test tubes... and they are rusting. One of the specifications I was given is it has to be chemical free water, so that rules out oxygen scavengers. Seeing as it is the dissolved oxygen I...
  43. C

    B The Most Primitive Star-Forming Galaxy Ever Found

    Lying 620 million light-years away, this galaxy has the lowest oxygen abundance ever seen in a star-forming galaxy. Link: New Scientist
  44. I

    What influences ignition temperature and oxygen consumption

    Hello, This is for my independent game development project. I am aiming to simulate simple environmental properties in grid-based world. I have world made of cells (or blocks) and I consider each physical property to be constant and uniform in given cell. Some properties spread from a cell to...
  45. M

    Light and oxygen acting upon the eye and the lung during the process of Evolution

    Did the evolution of the eye include interaction/reaction with a specific frequency of light? Did the evolution of the lung include interaction/reaction with the air density, humidity, and temperature of its environment?
  46. R

    Anyone have any experience with Oxygen meters?

    If anyone has used or uses an oxygen meter and could offer some advice it would be greatly appreciated. I degassed a solution of potassium iodide for 10 minutes each time and did experiments. However to get a more accurate measurement of the amount of O2 present I've decided to use an oxgen...
  47. E

    How would lower oxygen affect the greenhouse effect?

    If a terrestrial, earth-like planet had an atmosphere similar to Earth but with only around 15% oxygen concentration and 84% nitrogen, what impact would that have on the greenhouse effect of the planet's atmosphere? Are there other factors that would be relevant to calculating the greenhouse effect?
  48. M

    MHB Calculate Oxygen Mass at RT & Pressure: 78 cm3

    Calculate the mass of 78 cm3 of oxygen at room temperature and pressure . Im trying to work out the number of moles and then multiply by 32.
  49. physea

    Understanding Oxygen Pump Function | NGK 2008 News and Image

    hello! I want to know how oxygen pumps work. This photo displays one: http://www.ngk.co.jp/english/news/2008/image/0611_04.gif from: http://www.ngk.co.jp/english/news/2008/0611.html My question is, in order to pump the oxygen, does the oxygen have to go through the platinum electrode? or we...
  50. Robert House

    Fire suppression in a sealed system

    Here is the scenario. An astronaut is conducting experiments inside of a laboratory module within a space station when all of a sudden, a fire breaks out. The astronaut escapes from the laboratory module he was currently using and then proceeds to seal it off using an airlock. He then...
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