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] Impossible Heat Transfer Problem

  1. Oct 1, 2012 #1
    An insulated Thermos contains 122 g of water at 91°C. You put in a 13.7 g ice cube at 0°C to form a system of ice + original water.

    Use mc(ΔT) |water + mc(ΔT) |ice + Lm |ice = 0

    Final T = [(m*c*T) |water + (m*c*T) |ice - (L*m) |ice] / [m*c |water + m*c |ice]

    Final T = [(.122*4.18*364) + (.0137*2.108*273) - (334*.0137)] / [.122*4.18 + .0137*2.108]

    [STRIKE]Final T = 77.63K[/STRIKE]
    IS WRONG

    What am I doing wrong??
     
  2. jcsd
  3. Oct 1, 2012 #2

    256bits

    User Avatar
    Gold Member

    assuming you went from
    to
    What is L and why is it 334.
     
  4. Oct 1, 2012 #3
    In the denominator, you should be using the heat capacity of liquid water in both terms, since the ice is melted.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook