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At about 891 kJ/mol, methane's heat of combustion is lower than that of any other hydrocarbon, but the ratio of the heat of combustion (891 kJ/mol) to the molecular mass (16.0 g/mol, of which 12.0 g/mol is carbon) shows that methane, being the simplest hydrocarbon, produces more heat per mass unit (55.7 kJ/g) than other complex hydrocarbons.
2 He helium-4; Hoffer et al. 0.19085 g/cm 3 (from 20.9730 cm 3 /mole; hcp crystal melting to He-II superfluid at 0 K, 25.00 atm) : 0.19083 g/cm 3 (from 20.9749 cm 3 /mole; at local min. density, hcp melting to He-II: 0.884 K, 25.00 atm)
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 ...
8.17 kJ/mol Std entropy change of vaporization, Δ vap S o? J/(mol·K) Solid properties Std enthalpy change of formation, Δ f H o solid? kJ/mol Standard molar entropy, S o solid? J/(mol K) Heat capacity, c p? J/(mol K) Liquid properties Std enthalpy change of formation, Δ f H o liquid? kJ/mol Standard molar entropy, S o liquid? J/(mol K) Heat ...
Metallic hydrogen (recombination energy) 216 [2] Specific orbital energy of Low Earth orbit (approximate) 33.0: Beryllium + Oxygen: 23.9 [3] Lithium + Fluorine: 23.75 [citation needed] Octaazacubane potential explosive: 22.9 [4] Hydrogen + Oxygen: 13.4 [5] Gasoline + Oxygen –> Derived from Gasoline: 13.3 [citation needed] Dinitroacetylene ...
In all, the higher heating value of hydrogen is 18.2% above its lower heating value (142 MJ/kg vs. 120 MJ/kg). For hydrocarbons, the difference depends on the hydrogen content of the fuel. For gasoline and diesel the higher heating value exceeds the lower heating value by about 10% and 7%, respectively, and for natural gas about 11%.
The ideal gas equation can be rearranged to give an expression for the molar volume of an ideal gas: = = Hence, for a given temperature and pressure, the molar volume is the same for all ideal gases and is based on the gas constant: R = 8.314 462 618 153 24 m 3 ⋅Pa⋅K −1 ⋅mol −1, or about 8.205 736 608 095 96 × 10 −5 m 3 ⋅atm⋅K ...
In that case, the specific volume would equal 0.4672 in 3 /lb. However, if the temperature is changed to 1160 °R, the specific volume of the super heated steam would have changed to 0.2765 in 3 /lb, which is a 59% overall change. Knowing the specific volumes of two or more substances allows one to find useful information for certain applications.