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Because of helium's relatively low molar (atomic) mass, its thermal conductivity, specific heat, and sound speed in the gas phase are all greater than any other gas except hydrogen. For these reasons and the small size of helium monatomic molecules, helium diffuses through solids at a rate three times that of air and around 65% that of hydrogen ...
But helium — a nonrenewable element found deep within the Earth’s crust — is running low, leaving hospitals wondering how to plan for a future with a much scarcer supply.
Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures.Liquid helium may show superfluidity.. At standard pressure, the chemical element helium exists in a liquid form only at the extremely low temperature of −269 °C (−452.20 °F; 4.15 K).
Helium also has a very low boiling point (-268.9°C or -452°F), allowing it to remain a gas even in super-cold environments, an important feature because many rocket fuels are stored in that ...
The combination of helium’s extremely low molecular weight and weak interatomic reactions yield interesting properties when helium is cooled below its critical temperature of 5.2 K to form a liquid. Even at absolute zero (0K), helium does not condense to form a solid under ambient
Helium and hydrogen are two gases whose Joule–Thomson inversion temperatures at a pressure of one atmosphere are very low (e.g., about 40 K, −233 °C for helium). Thus, helium and hydrogen warm when expanded at constant enthalpy at typical room temperatures.
Helium and neon are also used as refrigerants due to their low boiling points. Industrial quantities of the noble gases, except for radon, are obtained by separating them from air using the methods of liquefaction of gases and fractional distillation. Helium is also a byproduct of the mining of natural gas.
While helium-4 is common on Earth, helium-3 is more readily found elsewhere in the cosmos, which is why scientists were surprised to detect a larger amount of the element than had been previously ...