jpblomberg
Mechanical
- Feb 1, 2006
- 3
Hello all,
When I am solving a thermodynamics (energy of compressed gas/liquid) problem, which cases should I use Enthalpy and which cases for Internal Energy? It has been 11 years since I took thermodynamics and I don't remember which one should be used.
Things I do remember: The Internal Energy of a substance includes the rotational and translation energy of the atoms/molecules that make up the substance. Enthalpy includes the Internal Energy + (Pressure * Volume). The units for both of these are the same, energy per mass.
I am not clear as to why some calculations use Internal Energy and some use Enthalpy. When is Internal Energy used and when is Enthalpy used?
Credo ut Intelligam -St. Augustine
When I am solving a thermodynamics (energy of compressed gas/liquid) problem, which cases should I use Enthalpy and which cases for Internal Energy? It has been 11 years since I took thermodynamics and I don't remember which one should be used.
Things I do remember: The Internal Energy of a substance includes the rotational and translation energy of the atoms/molecules that make up the substance. Enthalpy includes the Internal Energy + (Pressure * Volume). The units for both of these are the same, energy per mass.
I am not clear as to why some calculations use Internal Energy and some use Enthalpy. When is Internal Energy used and when is Enthalpy used?
Credo ut Intelligam -St. Augustine