Entropy Change Calculator
Entropy Change Calculator computes the entropy change (\\(\Delta S\\)) for a reversible process, such as heating a substance or an isothermal process, based on heat transfer, temperatures, and heat capacity.
Formulas Used in Entropy Change Calculator
The calculator computes entropy change based on the process type:
Heating (Constant \\(C_p\\)):
\\[ \Delta S = C_p \ln\left(\frac{T_2}{T_1}\right) \\]Isothermal Process:
\\[ \Delta S = \frac{q}{T} \\]Temperature Conversions:
\\[ T_K = T_C + 273.15 \\] \\[ T_K = \frac{5(T_F – 32)}{9} + 273.15 \\]Where:
- \\(\Delta S\\): Entropy change (kJ/(mol·K))
- \\(C_p\\): Molar heat capacity at constant pressure (kJ/(mol·K))
- \\(q\\): Heat added (kJ)
- \\(T_1, T_2\\): Initial and final temperatures (K)
- \\(T\\): Temperature for isothermal process (K)
- \\(T_C\\): Temperature in Celsius (°C)
- \\(T_F\\): Temperature in Fahrenheit (°F)
Example Calculation
Example: Heating with \\(C_p = 0.075 \, \text{kJ/(mol·K)}, T_1 = 298 \, \text{K}, T_2 = 373 \, \text{K}\\)
Compute: \\(\Delta S = 0.075 \ln\left(\frac{373}{298}\right)\\)
Result: \\(\Delta S \approx 0.017 \, \text{kJ/(mol·K)}\\)
Example: Isothermal with \\(q = 100 \, \text{kJ}, T = 298 \, \text{K}\\)
Compute: \\(\Delta S = \frac{100}{298}\\)
Result: \\(\Delta S \approx 0.336 \, \text{kJ/(mol·K)}\\)