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!

Latent heat

  1. Jul 31, 2009 #1
    1. The problem statement, all variables and given/known data
    You are given 2.5 102 g of coffee (same specific heat as water) at 70.0°C. In order to cool this to 60.0°C, how much ice (at 0.0°C) must be added? Neglect heat content of the cup and heat exchanges with the surroundings.

    2. Relevant equations
    Q=(m ice)(c ice)(delta T ice+ m ice)(Lf)
    Q=(m coffee)(c coffee)(delta T coffee)

    3. The attempt at a solution
    If these are the right formulas I still have the problem that there are 2 variables, since I don't know Q or m ice.
  2. jcsd
  3. Jul 31, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper

    The Q's in both equations are the same, energy lost by coffee = energy gained by ice.
    so you simply set the two equations equal to eahc other
  4. Jul 31, 2009 #3
    do you mean (m ice)(c ice)(delta T ice+ m ice)(Lf)=(m coffee)(c coffee)(delta T coffee)?
  5. Jul 31, 2009 #4


    User Avatar
    Science Advisor
    Homework Helper

    Almost, remember ther is energy to melt the ice (which doesn't depend on temperature) and then the energy to heat the resulting water to the final temperature.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Latent heat
  1. Latent heat (Replies: 4)

  2. Latent Heat (Replies: 8)

  3. Latent heat? (Replies: 6)