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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: netapparition on September 25, 2004, 03:22:30 PM

Title: Effusion and Kinetic Theory of Gases
Post by: netapparition on September 25, 2004, 03:22:30 PM
We have been given a thought provoking question that requires a relationship to be made between effusion and the kinetic theory of gases in the following question:

You are in the module of the Mir Space Station (ambient temperature 35.0 °C-- they are having trouble with the climate control) and notice a round hole 7.8 mm in diameter.  You look at the pressure gauge and see the pressure is now 0.17 atm.  (The atmosphere normally consists of 0.20 atm of pure oxygen (32 g/mole).  The cabin has a volume of 70.1 m^3.) How long has it been since the hole was formed?  

I am aware of the relationship (dp/dt)=(kT/V)(dN/dt), but am unsure how to apply the relationship to the above question.  The expression (dN/dt) can be derived by Graham's law of effusion.  

Please advise
Title: Re:Effusion and Kinetic Theory of Gases
Post by: Demotivator on September 25, 2004, 07:04:27 PM
First substitute for dN/dt , then integrate dp/dt
dN/dt =  Z  where Z is some expression
dp =  (kT/V)Z dt
integrate:
delta P =  (kT/V)Z(delta t)
Solve for delta t.