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Volume of a gas

  1. Nov 29, 2012 #1
    1. The problem statement, all variables and given/known data
    An electric generating plant boils water to produce high pressure steam. The steam spins a turbine that is connected to the generator.
    a) how many liters of water must be boiled to fill a 5.0 m^3 boiler with steam at 50 atm and 400 degrees Celsius.
    b) The steam has dropped to 2.0 atm at 150 degrees Celsius as it exits the turbine. How much volume does it now occupy?

    2. Relevant equations
    pv=nRT (not sure...but think you have to use some sort of ideal gas equation)

    3. The attempt at a solution
    Can you somehow find moles of the steam and then convert that to the liquid state somehow... do you use stochiometry?
  2. jcsd
  3. Nov 29, 2012 #2


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    Re: Homework help.. would be super appreciated

    I'd assume an ideal gas unless you've been told to do otherwise.

    If you can calculate the number of moles of water you need, then you can calculate the mass of water you need. Then just look up the density of water to get the volume.
  4. Nov 30, 2012 #3
    Do not use the ideal gas law. You are dealing with superheated water vapor. Use steam tables and find the specific volume of the steam at the indicated pressure and temperature. Since you know the volume you can determine the mass of the water vapor.
  5. Nov 30, 2012 #4


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    My advice would be to follow RTW69's advice, not mine.
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