Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Is delta enthalpy zero for

  1. Dec 12, 2009 #1
    Is delta enthalpy zero for....

    Is delta H, for an isothermal process in which a gas expands?
    delta H=delta U+work done,correct?
    delta U is 0,but work done = nCln(V2/V1).
    So,delta H is not equal to 0.But my book says so.
  2. jcsd
  3. Dec 12, 2009 #2


    User Avatar
    Science Advisor
    2017 Award

    Re: Is delta enthalpy zero for....

    No. deltaH = deltaU + delta(PV). Work done is p delta(V) (under conditions of constant pressure).

    For an ideal gas delta(PV) = R delta(nT). As long as the number of gas molecules in the system (n) and the temperature (T) remain constant, delta(PV) = 0.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook