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Topic: Gas Stoichiometry Question  (Read 3485 times)

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Offline blah2

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Gas Stoichiometry Question
« on: May 31, 2009, 03:15:04 PM »

A 2L storage tank contains F₂(g) at 125 kPa, and 303K. A 1L reaction vessel contained Xe(g) at 50.4 kPa and 303K. The F₂ was pumped into the reaction vessel containing the Xe and the reaction heated for a few hours. Allowing the reaction Xe + 2F₂ ->XeF4 to occur. After all the Xe had been used up, the reaction vessel cooled to 263K. Assuming all the XeF4 remained in solid phase, what pressure of F₂ remained in the reaction vessel?


I could only get so far, I am not able to find the volume of F₂ that reacted.

Here is my attempt:
Xe + 2F₂ ->XeF4
Since the two gases combine, the pressure is added.
Therefore P = 175.4 kPa
PV=nRT
n=PV/RT
n=(175.4kPa)(1L)/(8.31)(303K)
n=0.06966 mol Xe

Therefore 0.9966*2=molF2
=0.13932mol F2

Don't know where to go from here.

Offline Borek

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Re: Gas Stoichiometry Question
« Reply #1 on: May 31, 2009, 04:27:29 PM »
No, you can't add pressures, that's completely off.

How many moles of Xe in reaction vessel before F2 was added?

How many moles of F2 in storage tank before it was transferred to reaction vessel?
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Offline blah2

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Re: Gas Stoichiometry Question
« Reply #2 on: May 31, 2009, 04:39:05 PM »
Oh.
For F2
PV=nRT
n=(PV)/(RT)
n=(125kPa)(2L)/(8.31)(303K)
n=0.09929 mol

For Xe
n=PV/RT
n=(50.4kPa)(1L)/(8.31)(303K)
n=0.02002 mol

Offline Borek

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Re: Gas Stoichiometry Question
« Reply #3 on: May 31, 2009, 06:37:38 PM »
OK, now it is a limiting reagent question. Do you see it?
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Offline blah2

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Re: Gas Stoichiometry Question
« Reply #4 on: May 31, 2009, 06:57:21 PM »
I got it to the point where i found out the moles of F2 that is unreacted, but for pv=nRT, i need a volume, so i am stuck there.

Offline Borek

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Re: Gas Stoichiometry Question
« Reply #5 on: May 31, 2009, 07:17:39 PM »
What is a volume of a reaction vessel?
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Offline blah2

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Re: Gas Stoichiometry Question
« Reply #6 on: May 31, 2009, 07:42:18 PM »
oh 1 L, ty for your help  ;D

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