# Isobaric Process - Entropy

Written by Jerry Ratzlaff on . Posted in Thermodynamics

Isobaric process is a thermodynamic process where the pressure is kept constant, $$\Delta p = 0$$.

## Isobaric process - entropy Formulas

 $$\large{ S = \Delta S \; C_p \; \left[ ln \left( \frac{T_f}{T_i} \right) \right] }$$ $$\large{ S = \Delta S \; \left( n\; C_v \right) \; \left[ ln \left( \frac{T_f}{T_i} \right) \right] }$$

### Where:

 Units English Metric $$\large{ S }$$ = entropy $$\large{\frac{Btu}{lbm-R}}$$ $$\large{\frac{kJ}{kg-K}}$$ $$\large{ \Delta S }$$ = change in entropy $$\large{\frac{Btu}{lbm-R}}$$ $$\large{\frac{kJ}{kg-K}}$$ $$\large{ C_p }$$ = heat capacity at constant pressure $$\large{\frac{Btu}{R}}$$ $$\large{\frac{kJ}{K}}$$ $$\large{ C_v }$$ = heat capacity at constant volume $$\large{\frac{Btu}{R}}$$ $$\large{\frac{kJ}{K}}$$ $$\large{ ln }$$ = natural logarithm $$\large{dimensionless}$$ $$\large{ n }$$ = number of moles $$\large{dimensionless}$$ $$\large{ T_f }$$ = final temperature $$\large{R}$$ $$\large{K}$$ $$\large{ T_i }$$ = initial temperature $$\large{R}$$ $$\large{K}$$ 