What is an Isothermal Process?
An isothermal process is a thermodynamic transformation where the temperature of a system remains constant (ΔT = 0). This typically occurs when a system is in contact with an external thermal reservoir, and the change occurs slowly enough to allow the system to continually adjust to the temperature of the reservoir through heat exchange.
The Formula for Isothermal Work Done
For an ideal gas, the work done (W) during an isothermal expansion or compression is given by the following mathematical expression:
W = nRT ln(V₂ / V₁)
Where:
- n is the amount of substance (moles).
- R is the Ideal Gas Constant (8.314 J/mol·K).
- T is the absolute temperature in Kelvin.
- V₁ and V₂ are the initial and final volumes respectively.
How to Use This Calculator
To find the work done during an isothermal process, follow these steps:
- Enter the absolute temperature of the system in Kelvin. If you have Celsius, add 273.15.
- Input the number of moles of the gas involved.
- Define the starting volume (V1) and the ending volume (V2).
- Click "Calculate" to see the work done in Joules. A positive result indicates expansion (work done by the gas), while a negative result indicates compression (work done on the gas).
Frequently Asked Questions
Q: Does internal energy change in an isothermal process?
A: For an ideal gas, internal energy depends only on temperature. Since temperature is constant, the change in internal energy (ΔU) is zero.
Q: What is Boyle's Law?
A: Boyle's Law states that for a fixed amount of gas at constant temperature, Pressure is inversely proportional to Volume (P₁V₁ = P₂V₂).