1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Physics: Expansion at constant pressure

  1. Apr 8, 2012 #1
    An unknown number of moles of an ideal monoatomic gas expand reversibly from Vi = 2.30 m3 to Vf = 3.10 m3, at a constant pressure of 1.71 atm and an initial temperature of 300 K.
    Find the number of moles of gas.
    Find the final temperature of the gas K.
    Calculate the work done by the gas.

    I cannot find the number of moles and I don't know what I'm doing wrong.
    I'm using PV=nRT
    Converting the pressure in atm to N/m^2 and m^3 to L. I'm using the initial volume for V, 8.315 for R and the initial temp in K and solving for n. I keep getting the same answer and it is coming up wrong. Please help!
  2. jcsd
  3. Apr 8, 2012 #2


    User Avatar
    Gold Member

    Keywords are "ideal monoatomic gas expand reversibly "
    What does that mean to you?
  4. Apr 8, 2012 #3
    that's how much it fluctuate's?
  5. Apr 8, 2012 #4
    Can you show what you did (and how do you know is wrong)?
    The method (using equation of state for initial state) seems OK.
  6. Apr 9, 2012 #5
    Don't change m^3 to litres
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook