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!

Homework Help: Thermodynamics and Entropy- reservoir and block problem

  1. Sep 14, 2011 #1
    1. The problem statement, all variables and given/known data
    A 382 g block is put in contact with a thermal reservoir. The block is initially at a lower temperature than the reservoir. Assume that the consequent transfer of energy as heat from the reservoir to the block is reversible. Figure 20-22 gives the change in entropy ΔS of the block until thermal equilibrium is reached. The scale of the horizontal axis is set by Ta = 280 K and Tb = 520 K. What is the specific heat of the block?


    2. Relevant equations
    ΔS= mCspln(T/To)

    3. The attempt at a solution
    ΔS= mCspln(T/To)


    ΔS= 100 J/K
    m= .382 kg

    plug and chug,
    Csp= 100/(.382*ln(520/280)) =422.88J/K*kg

    where did I go wrong ):
  2. jcsd
  3. Sep 15, 2011 #2
    your T0 is not Ta

    look carefully at the graph^^
  4. Sep 17, 2011 #3

    Ohhhhh my gosh this is why i miss points on exams lol! Thanks c:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook