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It was first prepared by the free-radical reaction of cyclohexane using carbon disulfide as a sulfur source. [1]It is produced industrially by the hydrogenation of cyclohexanone in the presence of hydrogen sulfide over a metal sulfide catalyst:
Thermodynamic data is usually presented as a table or chart of function values for one mole of a substance (or in the case of the steam tables, one kg). A thermodynamic datafile is a set of equation parameters from which the numerical data values can be calculated. Tables and datafiles are usually presented at a standard pressure of 1 bar or 1 ...
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.
Enthalpy is the transfer of energy in a reaction (for chemical reactions, it is in the form of heat) and is the change in enthalpy. Δ H {\displaystyle \Delta H} is a state function, meaning that Δ H {\displaystyle \Delta H} is independent of processes occurring between initial and final states.
Hess's law states that the change of enthalpy in a chemical reaction is the same regardless of whether the reaction takes place in one step or several steps, provided the initial and final states of the reactants and products are the same. Enthalpy is an extensive property, meaning that its value is proportional to the system size. [4]
Std enthalpy change of vaporization, Δ vap H o: 32 kJ/mol Std entropy change of vaporization, Δ vap S o: 111.80 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) Enthalpy of transition, Δ trs H o: 6.7 kJ/mol at –87.0 °C crystal II ...
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
An enthalpy–entropy chart, also known as the H–S chart or Mollier diagram, plots the total heat against entropy, [1] describing the enthalpy of a thermodynamic system. [2] A typical chart covers a pressure range of 0.01–1000 bar , and temperatures up to 800 degrees Celsius . [ 3 ]