Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Kinetic theory and ideal gas

  1. Jul 26, 2011 #1
    1. The problem statement, all variables and given/known data
    An ideal gas in a cylinder occupies a volume of 0.065 m3 at room temperature (T = 293 K). The gas is confined by a piston with a weight of 100 N and an area of 0.65 m2. The pressure above the piston is equal to one atmosphere (atm = 1.013x10^5 Pa). The piston is free to move up and down.
    What is the pressure of the ideal gas?
    After heat is added (piston moves up), What is the pressure of the ideal gas?

    2. Relevant equations

    P= Patm + W/A

    3. The attempt at a solution

    For the first question, I found the pressure to equal 1.0145x10^5 Pa by using the equation I provided [P=1.013x10^5 + (100/.65)]

    Is that right?

    For the second question I figured the pressure would be the same because after the heat is added, the piston moves initially and then is again fixed in equilibrium (not moving). If there was a net force caused from a larger internal or external pressure, the piston would continue moving. But, since it is in equilibrium the pressure would stay the same...? The pressure builds up when the temp is increased, but since the piston is pushed up and stops, the volume has been increased resulting in equilibrium.
  2. jcsd
  3. Jul 27, 2011 #2


    User Avatar
    Homework Helper

    Good logic, your argument is right.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook