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!

Homework Help: Problem with ideal gas pressure

  1. Aug 13, 2008 #1
    1. The problem statement, all variables and given/known data

    Diagram here:
    http://img99.imageshack.us/img99/7189/systemgk9.jpg [Broken]

    Two bulbs, A of volume 100cm3 and B of volume 50cm3 , are connected to a three way tap T which enables them to be filled with gas or evacuated. The volume of the tubes may be neglected.
    Initially bulb A is filled with an ideal gas at 10oC to a pressure of 3.0 x 105 Pa. Bulb B is filled with an ideal gas at 100oC to a pressure of 1.0 x 105 Pa. The two bulbs are connected with A maintained at 10oC and B at 100oC. Calculate the pressure at equilibrium.

    2. Relevant equations
    PV = nRT

    3. The attempt at a solution

    I have the total Volume, total n but I can't find the final temperature of the system.

    I'm learning A-level Physics and this problem comes from a book, the Advanced Level Physics by Michael Nelkon. Please help me. Thank you in advance.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Aug 13, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    Initially you have [itex]P_A V_A=n_A R T_A[/itex] and [itex]P_B V_B=n_B R T_B[/itex]. You can figure out all of those numbers, right? Finally you have a new pressure [itex]P[/itex] and new molar numbers [itex]n'_A[/itex] and [itex]n'_B[/itex], three unknowns. So you need three equations to find them. You have two PV=nRT equations in the final state (one for each bulb) and [itex]n_A+n_B=n'_A+n'_B[/itex].
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook