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Scuba tanks get hot when you fill them. Putting them underwater keeps them cool. If they overheat, the burst disk may blow. But even if it doesn't, a "hot" fill will cool down to a lower pressure, so if you think you have filled the tank to 3,000 PSI, when it cools down you will find that you only have, say, 2,750 PSI in your tank.

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14y ago
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14y ago

As compressed air is added to a scuba cylinder the air entering the valve and moving within the cylinder creates heat. Cylinders are placed in water to dissipate this heat and keep the cylinder from overexpanding while still allowing the tank to be filled to its rated cylinder pressure.

As a cylinder expands with the heat from air entering the valve, if not placed in water, as the cylinder cools once the incoming air has stopped the pressure within the cylinder will decrease as cooler air molecules take up less space and therefore the pressure of warmer air once cooled will be a much lower rates psi within the cylinder.

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13y ago

The air you breathe in the atmosphere is about 70% Nitrogen and 12% Oxygen, You do not need 100% oxygen at any time unless you are injured or have trouble breathing. 100% Oxygen can scar your lungs, but when diving you need regular air to breathe. The problem with Nitrogen in the air we breathe while SCUBA diving is once you dive deeply enough, usually around 40M or 130 ft. you begin to suffer from Nitrogen Narcosis, a condition caused by breathing under extreme pressure. As 40M is not a 'Normal' dive. The way to alleviate the problem is to ascend to a shallower depth, that's why it is always Best to have a Dive Buddy.

The Bends is another factor, usually caused by ascending too quickly from a deep dive.

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The answer above is wrong and diverts from the question. Air is roughly 79% nitrogen and 21% oxygen. A scuba cylinder cannot be filled with pure oxygen because oxygen is toxic when it is breathed under pressure (i.e. at depth underwater). The depth and time limit for pure oxygen is 45 minutes at 20 feet and this is only used during special technical decompression dives. Exceeding this depth (or time limit) can result in underwater convulsions and result in drowning. Any extra percentage of oxygen used in a dive (including pure oxygen) requires special training.

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10y ago

The air we breathe is about 21% oxygen and 79% nitrogen. Less that one percent of our air is composed of trace gases like carbon dioxide and helium. This normal surface air is the breathing gas used by the vast majority of scuba divers.

There are a number of reasons why recreational scuba divers do not dive using pure oxygen. The first, and most important, of these is that oxygen is toxic to humans at the elevated pressures experienced in diving. While the exact depth limit varies with a diver's physiology, a good rule of thumb us that pure oxygen should not be used below about 27 feet of sea water. At that depth, the partial pressure of oxygen makes it toxic to most divers.

Pure oxygen IS used as the breathing gas in shallow water rebreathers like the Drager LAR V. These special purpose scuba rigs are used for combat swimmer delivery by highly trained combat divers such as US Navy SEALs. The oxygen toxicity depth limit still applies, even with these highly trained divers.

Pure oxygen is also used as a decompression gas at shallow depths by technical and commercial divers who have used other breathing gases during the dive.

Mixed gas rebreathers use pure oxygen as one of the two breathing gases which are mixed throughout a dive. Another diluent gas such as air is used to maintain optimum oxygen partial pressure for the diver to minimize both oxygen toxicity and decompression illness risk.

Another reason standard surface air is typically used to fill recreational scuba tanks is convenience and expense. Normal air is easy to obtain and inexpensive. Oxygen is difficult to work with and expensive.

Some recreational scuba divers do use a breathing gas called "Enriched Air Nitrox" (EANx). This is air to which oxygen has been added, increasing the percentage from 21% to as much as 40%. The increased oxygen reduces the amount of nitrogen, allowing longer dives without the risk of decompression illness.

It is important to note that pure oxygen can be very dangerous to work with due to the risk of fire and explosion. Diving gear that is to be used with breathing gases containing elevated levels of oxygen is designed with special seal materials and non-petroleum-based lubricants.

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6y ago

Because oxygen is toxic at high concentrations. If you breathed in pure oxygen, you would eventually get very sick.

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13y ago

they don't

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Q: Why cant a scuba filled with oxygen only?
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Which element has only on completely filled engery level?

Oxygen


Does atmospheric pressure have any effect on the oxygen level in the scuba tank?

No, only when it is released into the atmosphere at the ambient pressure.


Why cant you light a match in space?

No. Because there is no oxygen as there is only vacuum.


How ozone hole can be probably filled?

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Why only oxygen is not used in tanks of scuba divers?

Using only oxygen in scuba tanks for breathing underwater is not a common practice for several important reasons: Oxygen Toxicity: Breathing pure oxygen at elevated pressures, as experienced in scuba diving, can lead to oxygen toxicity. This condition can cause seizures, which can be extremely dangerous and potentially life-threatening. Oxygen toxicity typically occurs at partial pressures of oxygen (PPO2) greater than 1.4 to 1.6 atmospheres, which is encountered at relatively shallow depths when breathing pure oxygen. To avoid this risk, scuba divers must stay within safe oxygen exposure limits. Limited Depth Range: Using pure oxygen limits the depth to which divers can safely go without risking oxygen toxicity. It's suitable only for very shallow dives or for decompression stops during deeper dives. Recreational divers often wish to explore greater depths, and using pure oxygen would not allow this safely. Lack of Inert Gas: Pure oxygen does not provide the inert gas, such as nitrogen, that is typically used for dilution in breathing gases. Nitrogen helps reduce the risk of decompression sickness, also known as "the bends." Using pure oxygen for extended periods, especially at depth, can increase the risk of decompression sickness. Fire Hazard: Oxygen supports combustion, and using pure oxygen in scuba tanks increases the risk of fires. Scuba equipment and tanks need to be specifically designed for handling oxygen-rich gas mixtures to mitigate this risk. For recreational diving, the most commonly used breathing gas is air, which contains approximately 21% oxygen and 79% nitrogen. Divers can extend their dive times and depths by using gas mixtures with different oxygen and inert gas levels, such as nitrox, trimix, or heliox. These mixtures allow for a balance between the benefits of increased oxygen and the safety provided by inert gases like nitrogen or helium. Diving with specific gas mixtures is an essential aspect of scuba diving safety, and divers are trained to understand gas management and choose appropriate gas mixtures for their dive profiles to mitigate the risk of oxygen toxicity and decompression sickness.


Is the bond between hydrogen and oxygen an ionic bond?

No..It is hybridised to be precise.. See oxygen forms 3 sp2 hybrid orbitals with two half filled orbitals and one orbital filled with the lone pair.. hence the half filled orbitals are each filled by the hydrogen atoms respectively( as hydrogen requires only one atom for stability)..


Can humans breathe oxygen and hydrogen combine?

no it is completely different are bodies cant breathe that only pure oxygen(o2). although fish can breathe the dissolved oxygen in water


Is it possible to live in a area filled with carbo dioxide?

Dude, you already do live in an area filled with carbon dioxide. If you mean an area without oxygen, and only CO2, then no, it's not possible to breathe there. The only thing that can live there is plants.


Could life on earth if air contained only oxygen?

Not "life as we know it". Oxygen is poisonous, as all Scuba divers know; below about 30 feet depth, pure oxygen will kill you, and a few people react badly to oxygen in normal pressures. And without nitrogen and carbon dioxide, plants would be unable to live.


Why cant you breath underwater?

Because you have lungs and fish have gills.


Can you suffocate a cockroach?

Yes you can but only by draining all the oxygen. If the bedbug is in a room, and the oxygen is removed, this will also suffocate any other animals - and people.


Why must oxygen gas always be written as O2 in a chemical equation?

As oxygens only have 6 electrons, two oxygen molecules bond together to create a full shell.A single oxygen atom will never be present unless forced, as shells are always filled