1. Not finding help here? Sign up for a free 30min 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!

Phase Change

  1. Feb 11, 2009 #1
    Hoping someone could double-check for me....

    1. The problem statement, all variables and given/known data

    1) A 90 g block of unknown metal is heated to 86 degrees C and put in an insulated cup with 175 g water at 23 degrees C. At equilibrium, they are both 25.8 degrees C. What is the specific heat of the metal block?

    2) A well insulated cup contains 145 g of ice at 0 degrees C. We pour in 45 g watwer at 75 degrees C.
    a- Once equilibrium is established, how many grams of ice remain?
    b- What is the final temp in the cup?




    3. The attempt at a solution
    1) c ( 90 g) (-60.2 degrees c) + 1 cal/g degrees C) (175 g) (2.8degrees C) = 0
    c = 0.0904 cal/g degree C

    2)
    a- energy available to melt ice: 1 cal/ g Celcius (45 g) ( 75 degrees ) = 3375 cal
    energy needed to melt ice: 145 g (80 cal/g) = 11600 cal
    not all will melt

    80 cal /g (mass melted) = 3375 cal
    mass melted = 42.19 g

    b- Temp is 0 since there is still ice.
     
  2. jcsd
  3. Feb 11, 2009 #2

    Delphi51

    User Avatar
    Homework Helper

    Looks good to me!
     
  4. Feb 12, 2009 #3
    OK, great. Thanks for looking it over!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Phase Change
  1. Phase change (Replies: 7)

  2. Phase changes (Replies: 2)

  3. Phase Change (Replies: 0)

Loading...