Enthalpy: Pressure Change & Problem Solving

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SUMMARY

The discussion centers on the concept of enthalpy and its relationship with pressure changes. It clarifies that while enthalpy can change with pressure, it is not a requirement, contradicting some textbook assertions. The fundamental equation H=U+PV is highlighted, emphasizing that enthalpy can be simplified under specific conditions. Additionally, the discussion suggests that enthalpy is applicable in various scenarios, including constant volume processes, and encourages problem-solving using enthalpy in practical situations.

PREREQUISITES
  • Understanding of thermodynamic concepts, particularly enthalpy and internal energy.
  • Familiarity with the equation H=U+PV and its components.
  • Basic knowledge of calculus and algebra as they apply to thermodynamics.
  • Awareness of constant pressure and constant volume processes in thermodynamics.
NEXT STEPS
  • Explore the derivation and applications of the equation dH=dU+PdV+VdP.
  • Investigate real-world problems where enthalpy calculations are essential, such as in chemical reactions.
  • Study the implications of enthalpy changes in constant volume processes.
  • Learn about the role of enthalpy in phase transitions and heat transfer.
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Students and professionals in chemistry and engineering, particularly those focused on thermodynamics, chemical engineering, and energy systems.

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i understand enthalpy, what it is, how it changes. I have only two questions... first, as enthalpy changes the Pressure can change also (i know it doesent have to, but my book seems to be attempting to tell me that it never changes) and secondly could someone present a problem in which enthalpy could be usefull in solving? (only a concept for a problem would suffice)
 
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fortunately enthalpy has an fundamental description. H=U+PV. You can apply calculus, algebra...whatever, but it's not going to help you to assume any absolutes about such concepts. Enthalpy is useful for most situations, if you're given specific limitations, you can even simplify enthalpy to internal energy for instance.

enthalpy doesn't have to be constant pressure, dH=dU+PdV+VdP, and you don't need to have constant pressure, you can even apply enthalpy towards a constant volume process.
 
ohh.. duh its just a simplification (or an attempt therof) to help in the finding of volume or pressure or one of the other described variables.. as allways, thanks
 

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