摘要：Hess’s law is a version of the first law of thermodynamics that states that thetotalenthalpy changefor a reaction isindependentof

Hess’s law is a version of the first law of thermodynamics that states that the totalenthalpy changefor a reaction is independentof the route the reaction takes.

The mean bond enthalpy is the enthalpy change that is needed to break the covalent bond in gaseous molecules, averagedover a range of measurements.

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