Enthelpy so commonly described only in constant pressure situations?

Click For Summary
SUMMARY

Enthalpy is primarily described in constant pressure situations due to its simplicity in accounting for work and heat variations. While it can be applied in varying pressure environments, using enthalpy in these cases necessitates additional considerations for pressure changes. The use of enthalpy streamlines thermodynamic equations, making them more readable and manageable. This preference for constant pressure scenarios is rooted in the desire for clarity and efficiency in thermodynamic analysis.

PREREQUISITES
  • Understanding of thermodynamic potentials
  • Familiarity with the concept of enthalpy
  • Knowledge of Gibbs free energy
  • Basic principles of thermodynamics
NEXT STEPS
  • Explore the relationship between enthalpy and Gibbs free energy
  • Study the implications of varying pressure on enthalpy calculations
  • Learn about thermodynamic cycles involving enthalpy
  • Investigate practical applications of enthalpy in engineering
USEFUL FOR

This discussion is beneficial for students and professionals in thermodynamics, chemical engineers, and anyone involved in energy systems analysis who seeks to deepen their understanding of enthalpy and its applications.

pivoxa15
Messages
2,250
Reaction score
1
Why is enthalpy so commonly described only in constant pressure situations? It applies to change in pressure environments as well.
 
Science news on Phys.org
It is just a matter of taste: choosing what makes a balance simple or choosing to write a little longer balance equation.

The enthalpy can be related to other thermodynamic potentials.
It was probably defined to make things simpler. Try to re-write all the thermodynamics without the enthalpy or without the Gibbs free energy, you will see that some chapters will grow in page number and will be much less readable. That's all, I think.

When pressure is kept constant, work or heat can be accounted directly in terms of enthaply variations.
If pressure is not kept constant, you can still use enthalpy in the accounting but you will need to include not only the effect of work or heat but also the effect of pressure variation.
 
Last edited:

Similar threads

High School Gas cylinder at constant pressure being exposed to atmosphere, how?
  • · Replies 8 ·
Replies
8
Views
3K
Undergrad Availability at fixed pressure and temperature
  • · Replies 10 ·
Replies
10
Views
2K
Undergrad Enthalpy change in a flow process
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad How can heat change be measured under constant pressure?
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad External Pressure vs. Internal Pressure when considering work
  • · Replies 16 ·
Replies
16
Views
8K
Graduate Confused about use of external vs internal pressure in thermodynamics
  • · Replies 13 ·
Replies
13
Views
4K
Graduate How Safe Is The Constant Pressure Assumption For Enthelpy?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Calculating Entropy & Enthalpy: SRK, Wilson, Antoine & Clausius-Clapeyron
  • · Replies 5 ·
Replies
5
Views
3K
Undergrad Why work is PdV and not (P+dP)dV in an isothermal process?
  • · Replies 6 ·
Replies
6
Views
1K
Undergrad Pressure delta 1.0 bar: 0.0 to 1.0 vs 1.0 to 2.0
  • · Replies 10 ·
Replies
10
Views
2K