1. Not finding help here? Sign up for a free 30min 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!

Finding the mass of a quantity of gas given P, V, T

  1. Jan 10, 2016 #1
    1. The problem statement, all variables and given/known data

    A welder using a tank of volume 8.00×10−2 m^3 fills it with oxygen (with a molar mass of 32.0 g/mol ) at a gauge pressure of 3.10×105 Pa and temperature of 38.9 ∘C. The tank has a small leak, and in time some of the oxygen leaks out. On a day when the temperature is 23.0 ∘C, the gauge pressure of the oxygen in the tank is 1.75×105 Pa .

    Find the initial mass of oxygen.

    2. Relevant equations

    pV=nRT
    where p is pressure, v is volume, n is number of mole, R is 8.31442(since p is Pa and V is in m^3), and T is kelvin.
    m total = n*M ; where n is number of moles and M is molar mass.
    3. The attempt at a solution

    pV = nRT

    = 3.10 * 10^5 * 8.00 * 10^(-2) = n*8.314472* 312.05

    n = 9.558

    9.558 * 0.032 kg/mol = 0.305856

    however, 0.305856 is incorrect. where did i make mistake?
     
  2. jcsd
  3. Jan 10, 2016 #2

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Gauge pressure.
     
  4. Jan 10, 2016 #3
    thank you for replying, but can you please explain more specific, please?
     
  5. Jan 10, 2016 #4

    Bystander

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    What is the definition of "gauge pressure?"
     
  6. Jan 11, 2016 #5

    gneill

    User Avatar

    Staff: Mentor

    Mentor's note: Thread title has been changed to make it descriptive of the problem.
     
  7. Jan 12, 2016 #6

    rude man

    User Avatar
    Homework Helper
    Gold Member

    Did you take cognizance of the fact that n has changed?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Finding the mass of a quantity of gas given P, V, T
Loading...