 # Is the enthalpy change 0 only for ideal gases in an isothermal reaction or for real gases as well?

Is the enthalpy change 0 only for ideal gases in an isothermal reaction or for real gases as well?

I think you made a mistake it is not enthalpy it should be internal energy change.

I guess it's enthalpy only as for enthalpy= U+PV, So ∆ H= ∆U+∆(PV). This implies ∆H=∆U+nR∆T now as ∆T is 0 so ∆H is 0 as ∆ U is 0 as well...This is for ideal gases...Is there any equation which proves enthalpy change is 0 for or not for real gases?

In a real gas, we don't usually see stuff like internal energy remaining constant due to non ideal conditions. So it's for ideal gas only.

Hello, i think the enthalpy change is not zero for solids, liquids and real gases. As, the H = f (Temp, Pressure) and on partial differentiate del H = (del H/ del T) dT + (del H/del P) dP . This is the general expression for ∆H and it is valid for real gases also. Even, ∆U ≠ 0 for real gases.
For ideal gases,
The term in second bracket becomes zero as we know that in ideal gas the particles are of negligible size and hence exert no Pressure..

Hope it will help....

1 Like