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: Energy in change of phase

  1. Feb 3, 2013 #1
    I have been given the following problem:

    How much heat is needed to change 50.0g of water at 80.0°C to steam at 110°C?

    The equations that I have used are the following:

    Q = mCΔT
    Q = mL

    I've set up my equation as such:

    Q = mCΔT + mL

    However, I am unsure if I should leave it as it is and solve it or if one more 'mCΔT' is needed. I've used the first mCΔT to find the energy that takes the water to 100.0°C and the latent heat of vaporization to find the energy required to change the phase to steam. Do I need one more 'mCΔT?' or do I solve it as it is? If I need to add one more, would the specific heat capacity needed differ in any way?

  2. jcsd
  3. Feb 3, 2013 #2
    You have to raise the steam from 100 C to 110 C so you require another mCΔT.
  4. Feb 3, 2013 #3
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook