1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I Is enthalpy change during isothermal process zero?

  1. Dec 2, 2016 #1
    is enthalpy change during isothermal process zero? if it is zero then what is the significance of enthalpies like enthalpy of vapourization or fussion since during phase transformation temperature remains constant.
  2. jcsd
  3. Dec 2, 2016 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    H = U +PV so dH =dU + PdV + VdP. For an ideal gas, dU =0 for an isothermal process, so dH = PdV +VdP.

    For melting ice which occurs at constant T, there may be negligible change in P and V, but is ΔU =0?

  4. Dec 2, 2016 #3
    You answered your own question. Enthalpy is not just a function of temperature. It is also a function of pressure, state of aggregation, and chemical composition.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted