Deep-sea diving

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... 

Dr. Joseph Macinnis has a medical degree, but he does not work in a clinic, a hospital, or a typical doctor s office. His office is the ocean, and he is an expert in deep-sea diving. He combines his medical expertise with his knowledge of the properties of gases to study the effects of deep-sea diving on humans. 

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... 

Nitrogen (N2) is responsible for the bends, a potentially fatal problem associated with deep-sea diving. How many moles of N9 are there in 9.5 x 1018 molecules of... 

Applications in enhanced combustion and life-support systems provide the majority of the demand for oxygen. It is used extensively in medical applications for therapeutic purposes, for resuscitation in asphyxia, and with other gases in anesthesia. Also it is used in high-altitude flying and deep-sea diving, and it is used for life-support and as a fuel oxidizer in the U.S. space program.1... 

B22. Behnke, A. R., Jr., Physiologic studies pertaining to deep sea diving and aviation especially in relation to the fat content and composition of the body. Harvey Lectures 87, 198-226 (1941). 

This convenient method has been used successfully to keep air breathable for humans living in extreme environments like deep-sea diving apparatuses, submarines, space suits, and spacecraft. One of the many serious problems that occurred during the Apollo 13 lunar mission involved LiOH canisters that didn t fit the air purification system. 

Helium (He) is a valuable gas used in industry, low-temperature research, deep-sea diving tanks, and balloons. How many moles of He are in 6.46 g of He ... 

The helium we use for deep-sea diving and filling balloons is separated from natural gas as it is brought to the surface. This helium was formed in the depths of the earth by radioactive decay and remains trapped with the natural gas deposits. 

Helium was identified by its characteristic emission spectrum as a component of the sun before it was found on earth. The major sources of helium on earth are natural gas deposits, where helium was formed from the a-particle decay of radioactive elements. The a particle is a helium nucleus that can easily pick up electrons from the environment to form a helium atom. Although helium forms no compounds, it is an important substance that is used as a coolant, as a pressurizing gas for rocket fuels, as a diluent in the gases used for deep-sea diving and spaceship atmospheres, and as the gas in lighter-than-air airships (blimps). 

Soda lime eonsists of hydrated lime treated with caustic soda solution. It is used for absorbing carbon dioxide from air in medical, deep sea diving and military applications. It is manufactured by mixing hydrated lime with about 3 % of caustic soda and sufficient water to enable the paste to be extruded into pellets some 4 mm in diameter and 8 to 15 mm long. The pellets are then dried, screened and re-hydrated to a moisture content of about 20 %. 

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