I have a sealed container with a volume of 1 liter. I want to go from an initial pressure of $p_1 = 1\text{ atm}$ and an initial temperature of $T_1=298\text{ K}$ to a final pressure of $p_2=9.95\text{ atm}$ and a final temperature of $T_2=453\text{ K}$.

I want to to use water to create the pressure. But I do not know how to determine the amount of water, how would I do that?

  • $\begingroup$ How do you think you can have water at 453K which is 197 degree Celsius?Boiling point of water is 100 degree Celsius. Also, if you are going by ideal gas equation, it's applicable to gas only. So, try considering steam power. $\endgroup$
    – xCodeZone
    Dec 5 '16 at 1:56
  • $\begingroup$ please read again my question. I put water in sealed container and then give temperature. temerature cause increasing pressure ( Antoine equation Log P= a-b/c+T, a,b,c are Antione constant). my problem is that do not know how to determine the amount of water! $\endgroup$
    – EMHA
    Dec 5 '16 at 2:46
  • $\begingroup$ Possible duplicate of Is there an ideal proportion for water to air in an espresso machine? $\endgroup$ Dec 5 '16 at 5:23

The equilibrium vapor pressure of water at 180 C is about 10 bars. If you add the pressure of the air in the head space, that would give a pressure of over 11 bars. So, you need to evaporate all the water you initially have in the container to keep the final pressure below 10 bars.

A total pressure of 10 bars is not too high for the ideal gas law to provide a pretty good approximation. Assume that the initial amount of liquid water in the container was very low. How much water would have to be present along with an initial volume of 1 liter of air for the final total pressure to be 10 atm? Once you have this result, you can check it (and improve it, if necessary) by treating the final mixture as a non-ideal gas and taking into account the initial volume of the liquid water.


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