# Process such as isobaric, isochoric, quasistatic, adiabatic

1. May 28, 2009

### cos(e)

Just say an ideal gas goes through process such as isobaric, isochoric, quasistatic, adiabatic etc, is there any special cases where entropy is conserved, or am i thinking enthalpy. Also how is enthalpy found in adiabatic processes?

2. May 28, 2009

### Mapes

Re: entropy

Total entropy is conserved in reversible processes. System entropy is conserved in reversible processes without heat flow (reversible work doesn't carry entropy).

For an ideal gas, enthalpy $H$ is $nc_PT+H_0$, so for any process $\Delta H=nc_P\Delta T$.

3. May 28, 2009

### cos(e)

Re: entropy

do we use delta H= n*Cp* delta T even when the pressure is not constant?

What do u mean by reversible process, i havnt learnt that yet :S

4. May 28, 2009

### Mapes

Re: entropy

For an ideal gas; it's a special case.

A reversible process is an idealization in which no gradients exist in temperature, pressure, or any intensive properties. It's not realizable in real life, where the only way to transfer energy is by differences in temperature, pressure, etc. But if we assume the differences are small enough to be negligible, it makes the calculations easier precisely because we can assume that entropy generation is zero. More http://en.wikipedia.org/wiki/Reversible_process_(thermodynamics)" [Broken].

Last edited by a moderator: May 4, 2017