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enthalpy Definition

en·thalpy (en t̸hal′pē, en′t̸həl pē)

noun

a measure of the energy content of a system per unit mass

Etymology: Gr enthalpein, to warm in (< en-, en- < en, in + thalpein, to heat) + -y

enthalpy Usage Examples

Preposition: of

  • vaporization: The data is calculated from the variation with temperature of the pK w and enthalpy of vaporization.
  • combustion: Investigate the difference in enthalpy of combustion for a number of alcohols.
  • fusion: The heat energy required to convert 1 mole of solid into a liquid at its melting point is called the enthalpy of fusion.
  • formation: Here is a very useful equation that follows from the definition for enthalpy of formation.
  • ion: The main reason, tho, is the very high hydration enthalpy of the fluoride ion.
  • reaction: This is the enthalpy of reaction, &#068; H.

Converse of object

calculate: Table 2 shows calculated enthalpy of formation for some fluorinated reagents.

Adjective modifier

  • molar: Now simply add together the molar bond enthalpies involved for the reactants to obtain a total endothermic value.
  • specific: A second fluid 'B ' with a specific enthalpy of 160 kJ/kg also flows into the tank at a steady rate.
  • total: Again, it is impossible to know the total enthalpy ( heat energy content ) of the oxygen.
  • positive: Thus, there is an overall positive enthalpy of unfolding at higher temperatures.
  • standard: Example ii ) The standard enthalpy of formation of ethane represented by: .. ... ... ... ... .
  • low: Note: The reason for fluorine's low bond enthalpy is described on another page.

Modifies a noun

  • change: The symbol used for standard enthalpy changes is D H 298.
  • datum: The enthalpy data were obtained by integrating the specific heat capacity polynomial for each compound.

Noun used with modifier

  • hydration: The hydration enthalpy offsets the enthalpy change in breaking up the lattice.
  • lattice: The first is the comparatively very high lattice enthalpy of the solid fluoride.
  • dissociation: The term we are using here should more accurately be called the " lattice dissociation enthalpy " .
  • bond: Also... Bond enthalpy values apply to molecules in the gaseous state.
  • reaction: We call the heat changes associated with chemical reactions enthalpy changes ( D H ).