Skip to main content

Isobaric Process - Entropy

 

Isobaric Process - Entropy Formula
\( S  \;=\;  \Delta S \cdot C_p \cdot \left( ln \cdot \dfrac{ T_f }{ T_i } \right)  \) 
Symbol English Metric
\( S \) = Entropy \(Btu \;/\; lbm-R\) \(kJ \;/\; kg-K\)
\( \Delta S \) = Entropy Change \(Btu \;/\; lbm-R\) \(kJ \;/\; kg-K\)
\( C_p \) = Heat Capacity at Constant Pressure \(Btu \;/\; R\) \(kJ \;/\; K\)
\( ln \) = Natural Logarithm \(dimensionless\) \(dimensionless\)
\( T_f \) = Final Temperature \(R\) \(K\)
\( T_i \) = Initial Temperature \(R\) \(K\)

 Isobaric process in thermodynamics is a process that occurs at constant pressure.  During an isobaric process, entropy changes directly correlate with changes in temperature since pressure is constant.

Key Points about Isobaric Process - Entropy

Isobaric Process  -  The pressure of the system remains constant while other parameters like volume and temperature might change.
Entropy Change  -  Entropy changes during an isobaric process because entropy is a function of both heat and temperature.
If heat is added to the system (increasing temperature), entropy increases because there's more disorder or randomness in the system.
If heat is removed (decreasing temperature), entropy decreases, leading to a more ordered state.

P D Logo 1

Isobaric Process - Entropy Formula
\( S  \;=\;   \Delta S \cdot ( n \cdot C_v) \cdot  \left( ln \cdot \dfrac{ T_f }{ T_i } \right)  \) 
Symbol English Metric
\( S \) = entropy \(Btu \;/\; lbm-R\) \(kJ \;/\; kg-K\)
\( \Delta S \) = Entropy Change \(Btu \;/\; lbm-R\) \(kJ \;/\; kg-K\)
\( n \) = Number of Moles \(dimensionless\) \(dimensionless\)
\( C_v \) = Heat Capacity at Constant Pressure \(Btu \;/\; R\) \(kJ \;/\; K\)
\( ln \) = Natural Logarithm \(dimensionless\) \(dimensionless\)
\( T_f \) = Final Temperature \(R\) \(K\)
\( T_i \) = Initial Temperature \(R\) \(K\)