Dalton's Law and Partial Pressure

AI Thread Summary
The discussion focuses on applying Dalton's Law and calculating total and partial pressures in gas mixtures. The first calculation involves determining the total pressure in an 83.00L cylinder with nitrogen, oxygen, and argon, resulting in a total pressure of approximately 6.60 atm. The second part examines the partial pressure of nitrogen in a 6.00L cylinder containing multiple gases, initially yielding a partial pressure of 2.79 atm before correcting for helium, leading to a revised total pressure of 13.95 atm and a partial pressure of nitrogen still calculated as 2.79 atm. Participants confirm the calculations are correct but highlight the importance of including all gas components. The thread emphasizes accuracy in calculations and the significance of considering all gases in a mixture.
Soaring Crane
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1) Determine the total pressure (in atm) inside a 83.00L cylinder containing 5.00 mole of nitrogen, 6.00 mole of oxygen, and 5.00 mole of argon at 417.00 kelvin.

P_total = (n1 + n2 + n3)*(RT/V)
P_total = (5.00 + 5.00 + 6.00 mol)*(0.08206*417.00 K/83.00 L) = 6.60E0 atm?? (correct sig. digits?)

2) Determine the partial pressure of nitrogen in a 6.00 L cylinder that contains 0.600 moles of oxygen, 0.600 moles of nitrogen, 0.800 moles of hydrogen, and 1.000 moles of helium at 340.00 kelvin.

P_N = X_N*(P_total)

X_N = (0.600 mol N)/(0.600 N + 0.600 mol O + 0.800 mol H) = 0.300

P_total = (0.600 + 0.600 + 0.800 mol)*(RT/V)

P_total = (2.000 mol)*(0.08206*340.00K/6.00 L) = 2.000 mol*(4.6501) = 9.30 atm

P_N = 9.30 atm(0.300) = 2.79E0 atm ? (correct sig. digits?)

Thank you.
 
Last edited:
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Are my calculations correct?

Thank you for any replies.
 
Yes, they are both correct
 
For #2, I just realized that I forgot to include the 1.000 mol He!


Now, is it this?

P_N = X_N*(P_total)

X_N = (0.600 mol N)/(0.600 N + 0.600 mol O + 0.800 mol H + 1.000 mol He) = 0.200

P_total = (0.600 + 0.600 + 0.800 mol + 1.000 mol)*(RT/V)

P_total = (3.000 mol)*(0.08206*340.00K/6.00 L) = 3.000 mol*(4.6501) = 13.95020 atm

P_N = 13.95020 atm(0.200) = 2.79E0 atm ? (correct sig. digits?)

Yet somehow I get the same answer!:redface:
 
(I didn't check your work- I only checked your answers. :-P )
 

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