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!

Entropy change for isobaric heating

  1. Mar 7, 2010 #1
    Hi guys, is this right?

    1. The problem statement, all variables and given/known data
    A mole of nitrogen is heated at constant external pressure of 1 atm from 25° C to 100° C. The heat capacity of nitrogen is 29.1 J/mol·K.

    Calculate ΔSsurr




    2. The attempt at a solution
    delta_S=Q/T = -1*29.1*75/373=-5.85 J/K

    (heat transferred to the system divided by T_surr which we assume to be equal to T_final)

    The solution in my lecture notes says -22 J/K, I can't see where that came from.
     
  2. jcsd
  3. Mar 7, 2010 #2

    lightgrav

    User Avatar
    Homework Helper

    even if they heat it "infinitely slow", it only goes up to about 6½ J/K ,
    no-where near 22 J/K .
    { they must've divided by 100 degrees C by mistake , rather than 373 K }
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook