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Bob
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 Posted: Thu May 31, 2007 9:23 am Post subject: Re: plz someone help with this problem relating to chemical |
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On Wed, 30 May 2007 09:18:47 +0200, Borek
<m.borkowski@delete.chembuddy.whats.com.invalid> wrote:
| Quote: |
On Wed, 30 May 2007 06:58:21 +0200, Bob <bbx107.XYZ@excite.XYZ.com> wrote:
OK, my bad, it's at 25 C.
and has water vapor in it
My take is that partial pressure of water is to be ignored. Seems like
basic pV=nRT question.
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Well, going back to the original question...
| Quote: |
The h2 is
collected over water at a temperature of 25c and a total pressure of
762 mmhg.
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If it says "collected over water" and "total pressure", I'd take the
water pressure into account. But who knows. The OP has vaporized.
bob |
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The_Man
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| Posted: Thu May 31, 2007 11:03 am Post subject: Re: plz someone help with this problem relating to chemical |
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On May 31, 12:23 am, Bob <bbx107....@excite.XYZ.com> wrote:
| Quote: |
On Wed, 30 May 2007 09:18:47 +0200, Borek
m.borkow...@delete.chembuddy.whats.com.invalid> wrote:
On Wed, 30 May 2007 06:58:21 +0200, Bob <bbx107....@excite.XYZ.com> wrote:
OK, my bad, it's at 25 C.
and has water vapor in it
My take is that partial pressure of water is to be ignored. Seems like
basic pV=nRT question.
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It's more than that. It is a "collection of gas over water" problem.
| Quote: |
Well, going back to the original question...
The h2 is
collected over water at a temperature of 25c and a total pressure of
762 mmhg.
If it says "collected over water" and "total pressure", I'd take the
water pressure into account.
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No. Once the water level reaches equilibrium during the experiment, it
means that the total pressure inside the collection vessel equalls the
atmospheric pressure. The atmospheric pressure is read using a
barometer. The pressure inside the vesel consists of two terms - the
partial pressure of the H2, and the partial pressure of the water
vapor.
The partial pressure of water vapor is well-tabulated (just look it up
in a table, based on the temperature). This procedure doesn't work for
gases which either recat with the water or dissolve in it.
| Quote: |
But who knows. The OP has vaporized.
bob |
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Bob
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| Posted: Fri Jun 01, 2007 7:33 am Post subject: Re: plz someone help with this problem relating to chemical |
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On 31 May 2007 03:34:26 -0700, The_Man <me_so_horneeeee@yahoo.com>
wrote:
| Quote: |
Well, going back to the original question...
The h2 is
collected over water at a temperature of 25c and a total pressure of
762 mmhg.
If it says "collected over water" and "total pressure", I'd take the
water pressure into account.
No.
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No what?
What you wrote below is simply an elaboration of what I said. I assume
you meant yes.
bob
| Quote: |
Once the water level reaches equilibrium during the experiment, it
means that the total pressure inside the collection vessel equalls the
atmospheric pressure. The atmospheric pressure is read using a
barometer. The pressure inside the vesel consists of two terms - the
partial pressure of the H2, and the partial pressure of the water
vapor.
The partial pressure of water vapor is well-tabulated (just look it up
in a table, based on the temperature). This procedure doesn't work for
gases which either recat with the water or dissolve in it.
But who knows. The OP has vaporized.
bob
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The_Man
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| Posted: Sat Jun 02, 2007 12:15 am Post subject: Re: plz someone help with this problem relating to chemical |
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On May 31, 10:33 pm, Bob <bbx107....@excite.XYZ.com> wrote:
| Quote: |
On 31 May 2007 03:34:26 -0700, The_Man <me_so_hornee...@yahoo.com
wrote:
Well, going back to the original question...
The h2 is
collected over water at a temperature of 25c and a total pressure of
762 mmhg.
If it says "collected over water" and "total pressure", I'd take the
water pressure into account.
No.
No what?
What you wrote below is simply an elaboration of what I said. I assume
you meant yes.
bob
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Yes, I misunderstood what you meant by "water pressure" - I though
maybe you had some notion of hydrostatic pressure, rather than the
water vapor pressure. But then I looked and saw your previous post. My
mistake :-)
| Quote: |
Once the water level reaches equilibrium during the experiment, it
means that the total pressure inside the collection vessel equalls the
atmospheric pressure. The atmospheric pressure is read using a
barometer. The pressure inside the vesel consists of two terms - the
partial pressure of the H2, and the partial pressure of the water
vapor.
The partial pressure of water vapor is well-tabulated (just look it up
in a table, based on the temperature). This procedure doesn't work for
gases which either recat with the water or dissolve in it.
But who knows. The OP has vaporized.
bob- Hide quoted text -
- Show quoted text - |
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Bob
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| Posted: Sat Jun 02, 2007 5:52 am Post subject: Re: plz someone help with this problem relating to chemical |
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On Fri, 01 Jun 2007 12:15:33 -0700, The_Man
<me_so_horneeeee@yahoo.com> wrote:
| Quote: |
On May 31, 10:33 pm, Bob <bbx107....@excite.XYZ.com> wrote:
On 31 May 2007 03:34:26 -0700, The_Man <me_so_hornee...@yahoo.com
wrote:
Well, going back to the original question...
The h2 is
collected over water at a temperature of 25c and a total pressure of
762 mmhg.
If it says "collected over water" and "total pressure", I'd take the
water pressure into account.
No.
No what?
What you wrote below is simply an elaboration of what I said. I assume
you meant yes.
bob
Yes, I misunderstood what you meant by "water pressure" - I though
maybe you had some notion of hydrostatic pressure, rather than the
water vapor pressure. But then I looked and saw your previous post. My
mistake 
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Thanks for clarifying!
I was a little sloppy with terminology there, tho it seemed ok in
context. I try to not spend too much energy with hit and run
questions, where the student posts a question but then does not enter
the discussion.
bob |
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