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  2. Abundance of the chemical elements - Wikipedia

    en.wikipedia.org/wiki/Abundance_of_the_chemical...

    The order of elements by volume fraction (which is approximately molecular mole fraction) in the atmosphere is nitrogen (78.1%), oxygen (20.9%), [20] argon (0.96%), followed by (in uncertain order) carbon and hydrogen because water vapor and carbon dioxide, which represent most of these two elements in the air, are variable components. Sulfur ...

  3. Van der Waals constants (data page) - Wikipedia

    en.wikipedia.org/wiki/Van_der_Waals_constants...

    The following table lists the Van der Waals constants (from the Van der Waals equation) for a number of common gases and volatile liquids. [ 1 ] To convert from L 2 b a r / m o l 2 {\displaystyle \mathrm {L^{2}bar/mol^{2}} } to L 2 k P a / m o l 2 {\displaystyle \mathrm {L^{2}kPa/mol^{2}} } , multiply by 100.

  4. Table of specific heat capacities - Wikipedia

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

    Note that the especially high molar values, as for paraffin, gasoline, water and ammonia, result from calculating specific heats in terms of moles of molecules. If specific heat is expressed per mole of atoms for these substances, none of the constant-volume values exceed, to any large extent, the theoretical Dulong–Petit limit of 25 J⋅mol ...

  5. Valence (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Valence_(chemistry)

    The valence is the combining capacity of an atom of a given element, determined by the number of hydrogen atoms that it combines with. In methane, carbon has a valence of 4; in ammonia, nitrogen has a valence of 3; in water, oxygen has a valence of 2; and in hydrogen chloride, chlorine has a valence of 1. Chlorine, as it has a valence of one ...

  6. Lifting gas - Wikipedia

    en.wikipedia.org/wiki/Lifting_gas

    Methane (density 0.716 g/L at STP, average molecular mass 16.04 g/mol), the main component of natural gas, is sometimes used as a lift gas when hydrogen and helium are not available. [citation needed] It has the advantage of not leaking through balloon walls as rapidly as the smaller molecules of hydrogen and helium. Many lighter-than-air ...

  7. Hydrocarbon - Wikipedia

    en.wikipedia.org/wiki/Hydrocarbon

    They are composed entirely of single bonds and are saturated with hydrogen. The formula for acyclic saturated hydrocarbons (i.e., alkanes) is C n H 2n+2. [1]: 623 The most general form of saturated hydrocarbons, (whether linear or branched species, and whether with or without one or more rings) is C n H 2n+2(1-r), where r is the

  8. Helium - Wikipedia

    en.wikipedia.org/wiki/Helium

    Under high pressures helium can form compounds with various other elements. Helium-nitrogen clathrate (He(N 2) 11) crystals have been grown at room temperature at pressures ca. 10 GPa in a diamond anvil cell. [130] The insulating electride Na 2 He has been shown to be thermodynamically stable at pressures above 113 GPa. It has a fluorite ...

  9. Template:Periodic table (micro) - Wikipedia

    en.wikipedia.org/wiki/Template:Periodic_table...

    No description. Template parameters [Edit template data] Parameter Description Type Status title title no description Unknown optional mark mark no description Unknown optional caption caption no description Unknown optional float float no description Unknown optional style style no description Unknown optional form form no description Unknown optional number number no description Unknown ...