Question

Why hydrogen and helium gases show heating effect in Joule Thomson expansion?

Answer 1

Showing of heating effects by a gas depends upon its temperature of inversion.

If the temperature of any gas is above than its temperature of inversion then shows heating effects. And if temperature of any gas is below than its temperature of inversion then shows cooling effects.

For hydrogen and helium, temperature of inversion is much lower than the ordinary room temperature. Hence, these gases show heating effects at ordinary room temperature while others do not.

Actually, temperature of inversion for hydrogen and helium is -80°c and -238°c respectively.

Answer 2

Answer:

Due to the low inversion temperature, hydrogen and helium experience heating during the Joule-Thomson expansion.

Explanation:

During a Joule-Thomson expansion, pV for an ideal gas remains constant. Because of this, the temperature does not change, the internal energy does not change, and the Joule-Thomson coefficient is zero.

What is Joule-Thomson effect?

Heat transfer serves as the foundation for the Joule Thomson effect. Additionally, all genuine gases expand at standard pressure and temperature; this phenomenon is exploited to liquefy gases. The temperature of inversion for hydrogen and helium is significantly lower than the ambient air temperature.

As a result, only these gases exhibit heating effects at standard room temperature.