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Topic: Partial Pressure of 2L of 20atm O2 and 4L of 10atm H2  (Read 4587 times)

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VinnyCee

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Partial Pressure of 2L of 20atm O2 and 4L of 10atm H2
« on: March 22, 2006, 08:32:55 PM »
There are three tanks, all initially closed to each other:

1) 2 Liters, with 20 atmosphere O2.

2) 1 Liter, with nothing in it.

3) 4 Liters, with 10 atmosphere H2.

What is the new total pressure when the system is opened?

The temperature is below 300K and the O2 and H2 react.


My work so far:

I balanced the O2 and H2 reaction to 2H2 + 2O2 = 2H2O + O2

But that wouldn't really matter because you just add the pressures to get the total pressure, right? So 20 atm + 10 atm = 30 atm TOTAL

I don't think it's right, please help.
« Last Edit: March 22, 2006, 08:33:41 PM by VinnyCee »

Offline AWK

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Re:Partial Pressure of 2L of 20atm O2 and 4L of 10atm H2
« Reply #1 on: March 23, 2006, 03:20:16 AM »
For stoichiometry of reaction you should calculate moles of H2 and O2
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Offline Hunt

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Re:Partial Pressure of 2L of 20atm O2 and 4L of 10atm H2
« Reply #2 on: March 23, 2006, 08:58:39 PM »
You need to find the new partial pressures in the container.
VT = 2 + 1 + 4 = 7 L

If no rxn occurs, and at const temp:

Pf-Hydrogen = Pi-HydrogenVi-Hydogen / VT

Pf-Oxygen = Pi-OxygenVi-Oxygen / VT

Pi-Hydrogen = 10 atm
Pi-Oxygen = 20 atm

Vi-Oxygen = 2 L
Vi-Hydrogen = 4 L

PT = Pf-Oxygen + Pf-Hydrogen

If a rxn occurs, then , I assume the water formed is in the liquid state. The reaction would be a complete one, combustion of Hydrogen. However, to find the pressures, we need to know how much Oxygen and Hydrogen are present. If the Temp is given, we can determine the number of moles and proceed to calculate the final pressure.

2H2(g) + O2(g) ---> 2H2O(l)

« Last Edit: March 23, 2006, 09:12:38 PM by Vant_Hoff »

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