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  2. Prices of chemical elements - Wikipedia

    en.wikipedia.org/wiki/Prices_of_chemical_elements

    Per-kilogram prices of some synthetic radioisotopes range to trillions of dollars. ... Helium: 0.0001785: 0.008 (2. ... (2.632 × 10 19 kg) 1.82: 13.6: 2019 ...

  3. Lifting gas - Wikipedia

    en.wikipedia.org/wiki/Lifting_gas

    The amount of mass that can be lifted by hydrogen in air per unit volume at sea level, equal to the density difference between hydrogen and air, is: (1.292 - 0.090) kg/m 3 = 1.202 kg/m 3. and the buoyant force for one m 3 of hydrogen in air at sea level is: 1 m 3 × 1.202 kg/m 3 × 9.8 N/kg= 11.8 N

  4. Scuba gas planning - Wikipedia

    en.wikipedia.org/wiki/Scuba_gas_planning

    A reasonable approximation is to use the volume at 20 °C, ignore the mass of helium and take all nitrox and air components to be 1.3 kg/m 3. Using these approximations the estimate for the previous example is: Mass of mixture = 0.7 × 0.024m 3 /bar × 232 bar × 1.3 kg/m 3 = 5.1 kg

  5. Liquid helium - Wikipedia

    en.wikipedia.org/wiki/Liquid_helium

    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).

  6. Helium storage and conservation - Wikipedia

    en.wikipedia.org/wiki/Helium_storage_and...

    To ensure that the revenue from future sales would amortize the cost, the Secretary of the Interior raised the price of high purity helium from $12 per thousand cubic feet to $35. [1] [4] This price jump was an incentive for private companies to enter the market and sell helium at lower prices. [1] [3] [4] By 1970, it also became evident that ...

  7. Table of specific heat capacities - Wikipedia

    en.wikipedia.org/wiki/Table_of_specific_heat...

    The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution of the fat and skin is approximately 24%. The specific heat of tissues range from ~0.7 kJ · kg1 · °C−1 for tooth (enamel) to 4.2 kJ · kg1 · °C−1 for eye (sclera). [13]

  8. Specific volume - Wikipedia

    en.wikipedia.org/wiki/Specific_volume

    The standard unit is the meter cubed per kilogram (m 3 /kg or m 3 ·kg1). Sometimes specific volume is expressed in terms of the number of cubic centimeters occupied by one gram of a substance. In this case, the unit is the centimeter cubed per gram (cm 3 /g or cm 3 ·g −1). To convert m 3 /kg to cm 3 /g, multiply by 1000; conversely ...

  9. Isotopes of helium - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_helium

    In Earth's atmosphere, the ratio of 3 He to 4 He is 1.343(13) × 10 −6. [5] However, the isotopic abundance of helium varies greatly depending on its origin. In the Local Interstellar Cloud, the proportion of 3 He to 4 He is 1.62(29) × 10 −4, [6] which is ~121 times higher than in Earth's atmosphere.