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Homework Help: Ideal gas question

  1. Nov 23, 2006 #1
    Here's an ideal gas law question:

    A scuba diver is 32 m below the surface of a lake, where the temperature is 5°C. He releases an air bubble with a volume of 12 cm^3. The bubble rises to the surface, where the temperature is 25°C. What is the volume of the bubble right before it breaks the surface? (Hint: Remember that the pressure also changes.)

    I thought it would be the following:

    Pressure @ 32m = 4.2atm, since 10m=1atm under water
    12cm^3=.012 litres
    5C= 278K

    Pressure @ 0m = 1atm
    V= unknown
    25C= 298K

    Then, use PV/T=PV/T... but apparently it's wrong - does anyone know why?
  2. jcsd
  3. Nov 23, 2006 #2
    seems right, whats the correct answer?
  4. Nov 23, 2006 #3


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    Staff Emeritus
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    Gold Member

    Should be fine, all you have to do is rearrange the final equation you wrote for the second volume and plug the numbers in.
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