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Homework Help: Energy Required to Change Water into Steam

  1. Jul 20, 2011 #1
    1. The problem statement, all variables and given/known data

    How much energy is required to change one-quarter of 8.0kg of water at 25 C into steam?

    The way I see it, the entirety of the 8.0kg of water must be brought from 25 C to 100 C, then only 2.0kg is changed to steam so...

    Specific heat capacity (of water) = 4200 J / kg C
    Latent heat of vaporization (of water) = 2.3 * 10^6 J/kg

    Q total = (8.0kg) (4200 J / kg C) (100-25) + (2.0kg) (2.3 * 10^6 J/kg)
    Q total = 7.12 * 10^6 J

    I'm not 100% sure if I'm doing this properly. Does this look correct?
     
  2. jcsd
  3. Jul 20, 2011 #2
    That looks correct to me!
     
  4. Jul 20, 2011 #3
    Cool, thanks!
     
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