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Homework Help: CO2 expansion rates

  1. Sep 24, 2007 #1
    I need a formula to figure out the expansion of CO2.
    Ex: if I'm at sea level, "room temp", I've got 1cubic foot of co2 at 120psi, What is the volume when its released to ambient air ?

    Can anyone help?

    Shawn
     
  2. jcsd
  3. Sep 24, 2007 #2

    mgb_phys

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    Any gas follows a law P V = n R T where P = pressure (pascals) V = volume (m^3), n is the number of moles (44g for CO2), R is a constant 8.3145 J/(mol K) and T is the absolute (kelvin ) temperature.

    Alternatively 44g of CO2 occupies 24litres at room temmp/pressure. The volume decreases linearly with pressure and increases linearly with absolute temperature.
     
  4. Sep 24, 2007 #3

    Gokul43201

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    That's a little confusing. To clarify, n is not 44g (which is the value of the molar mass).
     
  5. Sep 24, 2007 #4

    mgb_phys

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    Sorry, yes to make it clearer. n is the number of moles, each mole of CO2 weighs 44g.

    But you can work it all out from just knowing that P * V is constant so long as temperature doesn't change.
     
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