Enter the total number of moles, initial volume, and final volume of an ideal gas into the calculator to determine the change in Entropy.

## Entropy Formula

The following equation is used to calculate the change in entropy of an ideal gas.

E = n * R * ln(v2/v1)

- Where E is the change in Entropy (J/K)
- n is the number of moles
- R is the gas constant (8.3145 J/mol*K)
- v1 and v2 are the initial and final volumes respectively

## Entropy Definition

Entropy is defined as the resistance of a substance to convert thermal energy into mechanical work.

## Entropy Example

How to calculate entropy

**First, determine the number of moles.**Calculate the number of moles of the ideal gas being analyzed.

**Next, measure the initial volume.**Calculate or measure the initial volume of the gas.

**Next, measure the final volume.**Measure the final volume after the reaction or change.

**Finally, calculate the change in entropy**Calculate the change in entropy using the information from steps 1-3 and the formula above.

## FAQ

**What is Entropy?**

Entropy is a measure of energy per unit of temperature. In more specific terms, it’s a measure of the unavailability of system to convert thermal energy into mechanical work.

**How do you calculate Entropy?**

Entropy is typically measured as a change in entropy using the formula above. The formula only applies to ideal gases.