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Ethane (US: / ˈ ɛ θ eɪ n / ETH-ayn, UK: / ˈ iː θ eɪ n / EE-thayn) is a naturally occurring organic chemical compound with chemical formula C 2 H 6. At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petrochemical by ...
Standard enthalpy of formation is the enthalpy change when one mole of any compound is formed from its constituent elements in their standard states. The enthalpy of formation of one mole of ethane gas refers to the reaction 2 C (graphite) + 3 H 2 (g) → C 2 H 6 (g).
For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hess' law, which states that the sum of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction.
Std enthalpy change of formation, Δ f H o liquid? kJ/mol Standard molar entropy, S o liquid: 126.7 J/(mol K) Heat capacity, c p: 68.5 J/(mol K) at −179 °C Gas properties Std enthalpy change of formation, Δ f H o gas: −83.8 kJ/mol Standard molar entropy, S o gas: 229.6 J/(mol K) Enthalpy of combustion, Δ c H o: −1560.7 kJ/mol Heat ...
Regardless of the equation format, the heat of formation of a compound at any temperature is ΔH° form at 298.15 K, plus the sum of the heat content parameters of the products minus the sum of the heat content parameters of the reactants. The C p equation is obtained by taking the derivative of the heat content equation.
A representation of Hess's law (where H represents enthalpy) Hess's law of constant heat summation, also known simply as Hess's law, is a relationship in physical chemistry and thermodynamics [1] named after Germain Hess, a Swiss-born Russian chemist and physician who published it in 1840.
The Van 't Hoff equation relates the change in the equilibrium constant, K eq, of a chemical reaction to the change in temperature, T, given the standard enthalpy change, Δ r H ⊖, for the process. The subscript r {\displaystyle r} means "reaction" and the superscript ⊖ {\displaystyle \ominus } means "standard".
Enthalpy (/ ˈ ɛ n θ əl p i / ⓘ) is the sum of a thermodynamic system's internal energy and the product of its pressure and volume. [1] It is a state function in thermodynamics used in many measurements in chemical, biological, and physical systems at a constant external pressure, which is conveniently provided by the large ambient atmosphere.