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Homework Help: Determine the specific latent heat of vaporization of water

  1. Apr 10, 2008 #1
    1. The problem statement, all variables and given/known data
    from the following observations made during an experiment,determine the specific latent heat of vaporisation of water.

    initial mass of water 400g
    final mass of water 450g
    mass of calorimeter 200g
    initial temperature of water & calorimeter 16 degrees
    final temperature of water & calorimeter 70 degrees
    specific heat capacity of water 4200 j/kg degrees
    specific heat capacity of calorimeter 420 j/kg degrees

    2. Relevant equations

    Q= m hfg

    3. The attempt at a solution

    let suffix s = steam w = water and c = calorimeter

    -ms hfg = mw cw delta tw + mc cc delta tc + ms cw delta ts

    -50 = 400x4200x(70-16)+200x420x(70-16)+50x4200x(70-100)=88.956x10 6

    therefore 50/88.956x10 6 = 562.075 x 10 -9

    if someone would be so kind to check if this is right it will be much appreciated.
  2. jcsd
  3. Apr 11, 2008 #2
    i forgot to state the final mass of water is 450g the extra 50 is condensed steam please can someone tell me if this is right or some pointers if i have it wrong because this question is relevant to my coursework i dont want the answer just help.
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