Analysis of a silicon wafer exposed to the solar wind in space and returned by the crashed Genesis spacecraft has shown that the Sun has a higher proportion of oxygen-16 than does the Earth. Pure or nearly pure O2 use in diving at pressures higher than atmospheric is usually limited to rebreathers, or decompression at relatively shallow depths (~6 meters depth, or less),[109][110] or medical treatment in recompression chambers at pressures up to 2.8 bar, where acute oxygen toxicity can be managed without the risk of drowning. [65] 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. Organic compounds important in industry and commerce that are made by direct oxidation of a precursor include ethylene oxide and peracetic acid. [134], Oxygen toxicity to the lungs and central nervous system can also occur in deep scuba diving and surface supplied diving. Oxygen is the most abundant chemical element by mass in the Earth's biosphere, air, sea and land. [15] Oxygen constitutes 49.2% of the Earth's crust by mass[61] as part of oxide compounds such as silicon dioxide and is the most abundant element by mass in the Earth's crust. How fast is the molecule moving? Share Oxygen (O - Standard atomic weight), molar mass. Mass of one proton = 1.67262158 x 10-27 Kg, Mass of protons in one oxygen atom = 1.338097264 x 10-26 Kg, Mass of one neutron: 1.674927293 x 10-27 Kg, Mass of neutrons in one oxygen atom: 1.33994183 x 10-26 (for 8 neutrons). [89], In the field of astrobiology and in the search for extraterrestrial life oxygen is a strong biosignature. [87], Variations in atmospheric oxygen concentration have shaped past climates. [16] 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. Water-soluble silicates in the form of Na4SiO4, Na2SiO3, and Na2Si2O5 are used as detergents and adhesives. This class of compounds includes the heme proteins hemoglobin and myoglobin. [55], Fourteen radioisotopes have been characterized. Acetone ((CH3)2CO) and phenol (C6H5OH) are used as feeder materials in the synthesis of many different substances. Hydrogen atoms are covalently bonded to oxygen in a water molecule but also have an additional attraction (about 23.3 kJ/mol per hydrogen atom) to an adjacent oxygen atom in a separate molecule. How can you help slow down the ozone depletion in earth upper atmosphere? [3][139] Oxygen is the oxidant, not the fuel, but nevertheless the source of most of the chemical energy released in combustion. [93], Oxygen gas can also be produced through electrolysis of water into molecular oxygen and hydrogen. Deeper diving requires significant dilution of O2 with other gases, such as nitrogen or helium, to prevent oxygen toxicity.[109]. [117] On the other hand, the electrochemical synthesis of hydrogen peroxide from oxygen is a promising technology to replace the currently used hydroquinone-process. Molecular mass (molecular weight) is the mass of one molecule of a substance and is expressed in the unified atomic mass units (u). Reactive oxygen species also play an important role in the hypersensitive response of plants against pathogen attack. Breathing air is scrubbed of carbon dioxide by chemical extraction and oxygen is replaced to maintain a constant partial pressure. (I) At room temperature, an oxygen molecule, with mass of 26 10 31. Oxygen condenses at 90.20 K (−182.95 °C, −297.31 °F), and freezes at 54.36 K (−218.79 °C, −361.82 °F). x [65] A steady stream of oxygen gas is then produced by the exothermic reaction. [68] 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. [90][91][92], One hundred million tonnes of O2 are extracted from air for industrial uses annually by two primary methods. [15] Oxygen gas is the second most common component of the Earth's atmosphere, taking up 20.8% of its volume and 23.1% of its mass (some 1015 tonnes). This was calculated by multiplying the atomic weight of hydrogen (1.008) by two and adding the result to the weight for one oxygen (15.999). 2) Divide the substance's molar mass by Avogadro's Number. Oxygen is present in the atmosphere in trace quantities in the form of carbon dioxide (CO2). This is not a problem except for patients on mechanical ventilators, since gas supplied through oxygen masks in medical applications is typically composed of only 30%–50% O2 by volume (about 30 kPa at standard pressure). [55] 17O is primarily made by the burning of hydrogen into helium during the CNO cycle, making it a common isotope in the hydrogen burning zones of stars. The element is similarly found in almost all biomolecules that are important to (or generated by) life. From the formula (H 2 O), you know there are two hydrogen atoms and one oxygen atom. [54] All of the remaining radioactive isotopes have half-lives that are less than 27 s and the majority of these have half-lives that are less than 83 milliseconds. [k][141], Liquid oxygen spills, if allowed to soak into organic matter, such as wood, petrochemicals, and asphalt can cause these materials to detonate unpredictably on subsequent mechanical impact.[139]. [74], Reactive oxygen species, such as superoxide ion (O−2) and hydrogen peroxide (H2O2), are reactive by-products of oxygen use in organisms. 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. [16] 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. In chemistry, the formula weight is a quantity computed by multiplying the atomic weight (in atomic mass units) of each element in a chemical formula by the number of atoms of that element present in the formula, then adding all … I hope u like It .. Make sure To hit thanks We now know that a hydrogen atom has a mass of 1.6735 x 10-24 grams, and that the oxygen atom has a mass of 2.6561 X 10-23 grams. The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass. Hydrogen is a chemical element with atomic number 1 which means there are 1 protons and 1 electrons in the atomic structure.The chemical symbol for Hydrogen is H. With a standard atomic weight of circa 1.008, hydrogen is the lightest element on the periodic table. Now double the mass of one oxygen atom to get the mass of one molecule. Molecular nitrogen (N2) would … [65] Oxygen is used in oxyacetylene welding, burning acetylene with O2 to produce a very hot flame. Harvey, 1955, citing C.J.J. Cons. [97] Increased O2 concentration in the lungs helps to displace carbon monoxide from the heme group of hemoglobin. [69] 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. [65], Oxygen storage methods include high pressure oxygen tanks, cryogenics and chemical compounds. People who climb mountains or fly in non-pressurized fixed-wing aircraft sometimes have supplemental O2 supplies. Please remember that you need the molar mass first when trying to find the average mass of one molecule. The most stable are 15O with a half-life of 122.24 seconds and 14O with a half-life of 70.606 seconds. 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 O2. You use the periodic table to look up the mass of each atom (H is 1.01 and O is 16.00). Other animals use hemocyanin (molluscs and some arthropods) or hemerythrin (spiders and lobsters). Scientists assess this aspect of water quality by measuring the water's biochemical oxygen demand, or the amount of O2 needed to restore it to a normal concentration.[65]. We know its mass, which is 5.31 times 10 to the minus 26 kilograms. The mole (symbol: mol) is the unit of measurement for amount of substance in the International System of Units (SI). [111] Professional athletes, especially in American football, sometimes go off-field between plays to don oxygen masks to boost performance. In the present equilibrium, production and consumption occur at the same rate. 0.125 mol molar mass 32g mol -1 Moles F321 1 At room temperature, an oxygen molecule, with mass of 5.31x10 -26 kg, typically has a kinetic energy of about 6.21x10 -21 J. The O2 surrounding those planets is produced solely by the action of ultraviolet radiation on oxygen-containing molecules such as carbon dioxide. [53], Naturally occurring oxygen is composed of three stable isotopes, 16O, 17O, and 18O, with 16O being the most abundant (99.762% natural abundance). Molecular mass of oxygen (O 2) = 16 x 2 = 32 g. 1 mole of oxygen is 32 g = 32 x 10-3 kg. (1 u is equal to 1/12 the mass of one atom of carbon-12) How much money do you start with in monopoly revolution? [94][102][103] Normobaric oxygen administration at the highest available concentration is frequently used as first aid for any diving injury that may involve inert gas bubble formation in the tissues. Oxygen tents were once commonly used in oxygen supplementation, but have since been replaced mostly by the use of oxygen masks or nasal cannulas. O [130], Oxygen gas (O2) can be toxic at elevated partial pressures, leading to convulsions and other health problems. What word has 8 letters with the 4th letter is v? [72] The O2 remaining (after production of the water molecule) is released into the atmosphere.[f]. Oxygen was discovered by Carl Wilhelm Scheele, in Uppsala, in 1773. [100][101] 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. [98][99] Oxygen gas is poisonous to the anaerobic bacteria that cause gas gangrene, so increasing its partial pressure helps kill them. Oxygen is the chemical element with the symbol O and atomic number 8. [112], Other recreational uses that do not involve breathing include pyrotechnic applications, such as George Goble's five-second ignition of barbecue grills. Another air separation method is forcing air to dissolve through ceramic membranes based on zirconium dioxide by either high pressure or an electric current, to produce nearly pure O2 gas. Also, 1 mole of H2O have 6.023×10^23 molecules. [139] The fire that killed the Apollo 1 crew in a launch pad test spread so rapidly because the capsule was pressurized with pure O2 but at slightly more than atmospheric pressure, instead of the ​1⁄3 normal pressure that would be used in a mission. Some remote sensing scientists have proposed using the measurement of the radiance coming from vegetation canopies in those bands to characterize plant health status from a satellite platform. Therefore, mass of a single oxygen molecule is 5.35607818 x 10-26 kg. Examples of molecular weight computations: C[14]O[16]2, S[34]O[16]2. [75][76], An adult human at rest inhales 1.8 to 2.4 grams of oxygen per minute. [126], The NFPA 704 standard rates compressed oxygen gas as nonhazardous to health, nonflammable and nonreactive, but an oxidizer. The presence of large amounts of dissolved and free oxygen in the oceans and atmosphere may have driven most of the extant anaerobic organisms to extinction during the Great Oxygenation Event (oxygen catastrophe) about 2.4 billion years ago. Also, although each atom in a molecule is a particular isotope, we use the weighted average, or atomic mass, for each atom in the molecule. [63], Free oxygen also occurs in solution in the world's water bodies. [16] The most common method is fractional distillation of liquefied air, with N2 distilling as a vapor while O2 is left as a liquid. [62] Parts of the immune system of higher organisms create peroxide, superoxide, and singlet oxygen to destroy invading microbes. − [e] Many steps are involved, but the result is the formation of a proton gradient across the thylakoid membrane, which is used to synthesize adenosine triphosphate (ATP) via photophosphorylation. Why don't libraries smell like bookstores? [118][119], Most of the remaining 20% of commercially produced oxygen is used in medical applications, metal cutting and welding, as an oxidizer in rocket fuel, and in water treatment. [82] Even if there was much dissolved iron in the oceans when oxygenic photosynthesis was getting more common, it appears the banded iron formations were created by anoxyenic or micro-aerophilic iron-oxidizing bacteria which dominated the deeper areas of the photic zone, while oxygen-producing cyanobacteria covered the shallows. When oxygen declined, atmospheric density dropped, which in turn increased surface evaporation, causing precipitation increases and warmer temperatures. Among the most important classes of organic compounds that contain oxygen are (where "R" is an organic group): alcohols (R-OH); ethers (R-O-R); ketones (R-CO-R); aldehydes (R-CO-H); carboxylic acids (R-COOH); esters (R-COO-R); acid anhydrides (R-CO-O-CO-R); and amides (R-C(O)-NR2). [111] Available studies support a performance boost from oxygen enriched mixtures only if it is breathed during aerobic exercise. Convert grams Oxygen to moles or moles Oxygen to grams ›› Percent composition by element For reasons of economy, oxygen is often transported in bulk as a liquid in specially insulated tankers, since one liter of liquefied oxygen is equivalent to 840 liters of gaseous oxygen at atmospheric pressure and 20 °C (68 °F). Oxygen is a chemical element with symbol O and atomic number 8. [65] Ethylene is reacted with O2 to create ethylene oxide, which, in turn, is converted into ethylene glycol; the primary feeder material used to manufacture a host of products, including antifreeze and polyester polymers (the precursors of many plastics and fabrics). [60] About 0.9% of the Sun's mass is oxygen. Mer, no. The reactions are exothermic, so the temperature increases to 1,700 °C. Part of this rejection was due to the belief that atoms of one element would have no, Oxygen's paramagnetism can be used analytically in paramagnetic oxygen gas analysers that determine the purity of gaseous oxygen. Calculate the mass of oxygen atom and oxygen molecule in kg(O=16) We also know it's kinetic energy, and we know it's 6.21 time standing, the minus 21 the jewels, and we want to know what its velocity is. [70], A simplified overall formula for photosynthesis is:[71], Photolytic oxygen evolution occurs in the thylakoid membranes of photosynthetic organisms and requires the energy of four photons. In this problem, we have an oxygen molecule. 16 g ÷ 1000 = 0.016 kg. Free oxygen first appeared in significant quantities during the Paleoproterozoic eon (between 3.0 and 2.3 billion years ago). Cellular respiration using O2 enables aerobic organisms to produce much more ATP than anaerobic organisms. [121] Compounds containing oxygen in other oxidation states are very uncommon: −1/2 (superoxides), −1/3 (ozonides), 0 (elemental, hypofluorous acid), +1/2 (dioxygenyl), +1 (dioxygen difluoride), and +2 (oxygen difluoride). Fe It is also the major component of the world's oceans (88.8% by mass). 1 mole of a substance contains 6.022 x 10 23 molecules It is defined as exactly 6.022 140 76 × 10 23 particles, which may be atoms, molecules, ions, or electrons.. Atkins, P.; Jones, L.; Laverman, L. (2016). This preview shows page 2 - 4 out of 5 pages.. 15. The surface of most metals, such as aluminium and titanium, are oxidized in the presence of air and become coated with a thin film of oxide that passivates the metal and slows further corrosion. [127] An exotic and unusual reaction occurs with PtF6, which oxidizes oxygen to give O2+PtF6−, dioxygenyl hexafluoroplatinate.[128]. [109][j][132] Oxygen toxicity usually begins to occur at partial pressures more than 50 kilopascals (kPa), equal to about 50% oxygen composition at standard pressure or 2.5 times the normal sea-level O2 partial pressure of about 21 kPa. Chemical catalysts can be used as well, such as in chemical oxygen generators 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. 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. Hemoglobin binds O2, changing color from bluish red to bright red[39] (CO2 is released from another part of hemoglobin through the Bohr effect). 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. [4] The reaction for aerobic respiration is essentially the reverse of photosynthesis and is simplified as: In vertebrates, O2 diffuses through membranes in the lungs and into red blood cells. Sudden cabin pressure loss activates chemical oxygen generators above each seat, causing oxygen masks to drop. [104][105][106], An application of O2 as a low-pressure breathing gas is in modern space suits, which surround their occupant's body with the breathing gas. Thus, oxygen was assigned an atomic mass of 16. [55] Most 18O is produced when 14N (made abundant from CNO burning) captures a 4He nucleus, making 18O common in the helium-rich zones of evolved, massive stars. [54] The most common decay mode of the isotopes lighter than 16O is β+ decay[56][57][58] to yield nitrogen, and the most common mode for the isotopes heavier than 18O is beta decay to yield fluorine.[54]. [95], Hyperbaric (high-pressure) medicine uses special oxygen chambers to increase the partial pressure of O2 around the patient and, when needed, the medical staff. 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. [9][46] At 25 °C and 1 standard atmosphere (101.3 kPa) of air, freshwater contains about 6.04 milliliters (mL) of oxygen per liter, and seawater contains about 4.95 mL per liter. Oxygen reacts spontaneously with many organic compounds at or below room temperature in a process called autoxidation. (I) At room temperature, an oxygen molecule, with mass of 5.31x10-26 kg typically has a kinetic energy of … Fire and explosion hazards exist when concentrated oxidants and fuels are brought into close proximity; an ignition event, such as heat or a spark, is needed to trigger combustion. [16], The other primary method of producing O2 is passing a stream of clean, dry air through one bed of a pair of identical zeolite molecular sieves, which absorbs the nitrogen and delivers a gas stream that is 90% to 93% O2. Schmidt-Rohr, K. (2020). At room temperature, an oxygen molecule, with a mass of 5.31x10^-26 kg typically has kenetic energy of about 6.21x10^-21. [122], Water (H2O) is an oxide of hydrogen and the most familiar oxygen compound. [113], Smelting of iron ore into steel consumes 55% of commercially produced oxygen. At room temperature, an oxygen molecule, with mass of 5.31×10−26kg, typically has a kinetic energy of about 6.21×10−21J. [77] This amounts to more than 6 billion tonnes of oxygen inhaled by humanity per year. [107][133] In the case of spacesuits, the O2 partial pressure in the breathing gas is, in general, about 30 kPa (1.4 times normal), and the resulting O2 partial pressure in the astronaut's arterial blood is only marginally more than normal sea-level O2 partial pressure. Acute oxygen toxicity (causing seizures, its most feared effect for divers) can occur by breathing an air mixture with 21% O2 at 66 m (217 ft) or more of depth; the same thing can occur by breathing 100% O2 at only 6 m (20 ft). [66] Paleoclimatologists also directly measure this ratio in the water molecules of ice core samples as old as hundreds of thousands of years. [9], Breathing pure O2 in space applications, such as in some modern space suits, or in early spacecraft such as Apollo, causes no damage due to the low total pressures used. 9 of Tutorial chemistry texts), Cambridge, U.K.:Royal Society of Chemistry, p. 153, From The Chemistry and Fertility of Sea Waters by H.W. [124][i], Due to its electronegativity, oxygen forms chemical bonds with almost all other elements to give corresponding oxides. [51] The absorption in the Herzberg continuum and Schumann–Runge bands in the ultraviolet produces atomic oxygen that is important in the chemistry of the middle atmosphere. Refrigerated liquid oxygen (LOX) is given a health hazard rating of 3 (for increased risk of hyperoxia 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. Oxygen gas is increasingly obtained by these non-cryogenic technologies (see also the related vacuum swing adsorption). [9], At one time, premature babies were placed in incubators containing O2-rich air, but this practice was discontinued after some babies were blinded by the oxygen content being too high. [72] 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 2.5 billion years ago during the Great Oxygenation Event, about a billion years after the first appearance of these organisms. [50], Liquid oxygen is a highly reactive substance and must be segregated from combustible materials. [65], Another 25% of commercially produced oxygen is used by the chemical industry. There is epidemiological support for its use from a statistical study of cases recorded in a long term database. Oxygen therapy is used to treat emphysema, pneumonia, some heart disorders (congestive heart failure), some disorders that cause increased pulmonary artery pressure, and any disease that impairs the body's ability to take up and use gaseous oxygen. ***** INCLUDE APPROPRIATE UNITS FOR VELOCITY [81], Free oxygen gas was almost nonexistent in Earth's atmosphere before photosynthetic archaea and bacteria evolved, probably about 3.5 billion years ago. [94], Treatments are flexible enough to be used in hospitals, the patient's home, or increasingly by portable devices. 41, 1907. The mass of oxygen gas occupying a volume of 11.2 litres at a temperature $27^{\circ}C$ and a pressure of 1 atm in kilograms is (Molecular weight of oxygen … Photosynthesis releases oxygen into the atmosphere, while respiration, decay, and combustion remove it from the atmosphere. From Calculating the Mass of an Oxygen Atom and molecule from the periodic table. The measurement is technically difficult owing 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. The formula of an oxygen molecule is O2 (2 is a subscript but now WA doesn't permit to write a subscript).15.9994 g/mol is the molecular mass of oxygen. 6 21 How fast is the molecule moving? The unusually high concentration of oxygen gas on Earth is the result of the oxygen cycle. The average mass of an oxygen atom is 5.3 {eq}\\times {/eq} 10{eq}^{-26} {/eq} kg. [15][62][d] Earth is unusual among the planets of the Solar System in having such a high concentration of oxygen gas in its atmosphere: Mars (with 0.1% O2 by volume) and Venus have much less. At room temperature, an oxygen molecule, with mass of #5.31 x 10^-26 kg#, typically has a KE of about #6.21 x 10-21# J. A similar method is the electrocatalytic O2 evolution from oxides and oxoacids. ", "George Goble's extended home page (mirror)", "Surface chemistry of phase-pure M1 MoVTeNb oxide during operation in selective oxidation of propane to acrylic acid", "Multifunctionality of Crystalline MoV(TeNb) M1 Oxide Catalysts in Selective Oxidation of Propane and Benzyl Alcohol", "NFPA 704 ratings and id numbers for common hazardous materials", "The Four Most Important Equations In Clinical Practice", Roald Hoffmann article on "The Story of O", Scripps Institute: Atmospheric Oxygen has been dropping for 20 years,, Chemical substances for emergency medicine, Biology and pharmacology of chemical elements, Wikipedia articles incorporating a citation from the 1911 Encyclopaedia Britannica with Wikisource reference, Wikipedia indefinitely semi-protected pages, Wikipedia indefinitely move-protected pages, Short description is different from Wikidata, All Wikipedia articles written in American English, Articles containing Ancient Greek (to 1453)-language text, Creative Commons Attribution-ShareAlike License, This page was last edited on 30 December 2020, at 02:27. The pharmacological effect is doubted; a placebo effect is a more likely explanation. Molar mass of O = 15.9994 g/mol. Substances mass g or kg molar mass g mol-1 or kg mol-1 Example Calculate the number of moles of oxygen molecules in 4g oxygen molecules have the formula O2 the relative mass will be 2 x 16 = 32 so the molar mass will be 32g mol-1 moles = mass = 4g ANS. [135] Exposure to an O2 partial pressures greater than 160 kPa (about 1.6 atm) may lead to convulsions (normally fatal for divers). Planetary geologists have measured the relative quantities of oxygen isotopes in samples from the Earth, the Moon, Mars, and meteorites, but were long unable to obtain reference values for the isotope ratios in the Sun, believed to be the same as those of the primordial solar nebula. 10 12. Definitions of molecular mass, molecular weight, molar mass and molar weight. [52] Excited state singlet molecular oxygen is responsible for red chemiluminescence in solution. About Oxygen; 1 cubic meter of Oxygen weighs 1.429 kilograms [kg] 1 cubic inch of Oxygen weighs 0.000826014 ounce [oz] Oxygen weighs 0.001429 gram per cubic centimeter or 1.429 kilogram per cubic meter, i.e. That said it might not be a definite biosignature, being possibly produced abiotically on celestial bodies with processes and conditions (such as a peculiar hydrosphere) which allow free oxygen. Fox, "On the coefficients of absorption of atmospheric gases in sea water", Publ. Problem 34 Easy Difficulty (II) An oxygen molecule consists of two oxygen atoms whose total mass is $5.3 \times 10^{-26} \mathrm{kg}$ and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is $1.9 \times 10^{-46} \mathrm{kg} \cdot \mathrm{m}^{2} .$ From these data, estimate the effective distance between the atoms. ››More information on molar mass and molecular weight. When did organ music become associated with baseball? FREE Expert Solution Show answer. Seawater molecules that contain the lighter isotope, oxygen-16, evaporate at a slightly faster rate than water molecules containing the 12% heavier oxygen-18, and this disparity increases at lower temperatures. Explor. This trade-off of higher oxygen concentration for lower pressure is needed to maintain suit flexibility. 16. Marine organisms then incorporate more oxygen-18 into their skeletons and shells than they would in a warmer climate.