Pressure diving

From inhalation at pressures above atmospheric, used in tunnelling or diving, or from breathing apparatus or resuscitation equipment, if the pressure is too high or exposure is prolonged. This may cause symptoms from pain to dyspnoea, disorientation and unconsciousness it may be fatal. 

Self-Test 4.17A A 10.0-1. tank containing 25 mol 02 is stored in a diving supply shop at 25°C. Use the data in Table 4.5 and the van der Waals equation to estimate the pressure in the tank. 

The effect of high pressure on organisms, including humans, is studied to gain information about deep-sea diving and anesthesia. A sample of air occupied 1.00 L at 25°C and... 

The amount of gas introduced into a diving tank can be determined by weighing the tank before and after charging the tank with gas. A diving shop placed 80.0 g of O2 and 20.0 g of He in a 5.00-L tank at 298 K. Determine the total pressure of the mixture, and find the partial pressures and mole fractions of the two... 

The partial pressures are large, but diving tanks are built to stand high pressures. To check for consistency, add the mole fractions, which must sum to 1.00. 

Hyperbaric pressure may intensify odors or render odoriferous some odorless gases such as methane. Professional divers, experimentally exposed to hyperbaric pressures, detected odors of krypton and methane when sniffing these during the decompression phase of a dive. The threshold for krypton was 2 ATA (atmosphere absolute), and 100% positive responses occurred at 6 ATA. For methane, the threshold was 3 ATA (100% 13 ATA). The thresholds of individuals differed by as much as a factor of three (Laffort and Gortan, 1987). 

Another area in which the gas laws play a key role is in scuba diving. At the surface, we breath air at a pressure of approximately 1 atmosphere. The partial pressures of nitrogen and oxygen are 0.78 and 0.20 atmosphere, respectively. A scuba diver breaths compressed air that is delivered at a pressure that corresponds to the pressure at the depth of the diver. Because 33 feet of... 

Another example of a diving problem that is a direct consequence of Dalton s Law of partial pressure concerns oxygen toxicity. The deeper a diver descends, the greater the partial pressure of oxygen. At a depth of 130 feet, the total pressure is close to 5 atmospheres and the partial pressure of oxygen will be close to 1 atmosphere (21% X 5 atmospheres). What this means is that breathing compressed air at 130 feet is like... 

Filament-wound structures are often used to store fluid under pressure fuel storage tanks, rocket motor cases, natural gas, and oxygen storage tanks. In some cases, the filament-wound structure is subjected to external pressure a diving bell or submarine. Filament winding has... 

Then, by diving the total pressure drop by the bed length we obtain... 

Was this your answer As she rises to the surface the pressure decreases from 2 atmospheres to 1 atmosphere. Since the pressure halves, the volume of air in her lungs tends to double. A first lesson in scuba diving is not to holdyour breath while ascending.To do so can be fatal. 

In general living beings on the planet earth are behaving very differently with respect to their compatibility towards pressurized environment. Some species of microbes are able to suffer several thousand bar and there are sea mammals such as whales which dive down to a depth of 1000 m - equal to a pressure difference of 100 bar - within short time intervals, a procedure which would kill human beings immediately. 

Helium gas is twice as dense as hydrogen under the same conditions. However, because its density is still very low and it is nonflammable, it is used to provide buoyancy in airships such as blimps. Helium is also used to dilute the oxygen used in deep-sea diving, to pressurize rocket fuels, as a coolant, and in helium-neon lasers. The element has the lowest boiling point of any substance (4.2 K), and it does not freeze to a solid at any temperature unless pressure is applied to hold the light, mobile atoms... 

A helium-oxygen mixture is used in diving gas instead of compressed air (nitrogen-oxygen). If air were used, nitrogen would dissolve in the diver s blood at the high underwater pressures and would be released as painful bubbles when the diver returned to the surface. 

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