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!

Calculated the pressure of the alcohol

  1. Nov 27, 2007 #1

    sun

    User Avatar

    1. The problem statement, all variables and given/known data
    Air is trapped above liquid ethyl alcohol in a rigid container. If the air pressure above the liquid is 1.10atm, determine the pressure inside a bubble 4.0m below the surface of the liquid.

    Image: Think of a cylindrical container with a layer of air at the top. The remaining is filled with ethyl alcohol. 4m below the top of the alcohol is a bubble of air.

    2. Relevant equations

    P=P(atm)+pgh
    p(ethyl-OH)=.806X10^3kg/m^3

    3. The attempt at a solution

    So i calculated the pressure of the alcohol 4m below the surface and got 1.3X10^5Pa. However, i'm not sure what to do in order to get the pressure in the bubble.
    Suggestions would be appreciated.

    thanks
     
    Last edited: Nov 28, 2007
  2. jcsd
  3. Nov 27, 2007 #2

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    How did you go from a density of 0.8X10^3 to a pressure of 1.3X10^5? What units are all these quantities in?
     
  4. Nov 28, 2007 #3

    sun

    User Avatar

    This is what i did in order to get the pressure of the ethyl 4m down:

    P=1.01310^5Pa+(.806X10^-3kg/m^3)(9.8m/s^s)(4m)=1.33X10^5Pa
     
  5. Nov 28, 2007 #4

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Looks okay so far.

    Now, since they don't tell you the size of the bubble, you are probably expected to assume that the pressure inside the bubble is equal to the pressure of the liquid around it. So you've got the answer you need.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Calculated the pressure of the alcohol
  1. Pressure Calculation (Replies: 11)

Loading...