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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: raney nickel on September 12, 2013, 03:42:56 PM

Title: gas expansion problem
Post by: raney nickel on September 12, 2013, 03:42:56 PM
Hi, I'm trying to learn a little Pchem and I was wondering if someone could walk me through ths problem:

A careless worker has thrown 1.0 g Zn into an apparatus containing a large amount of aqueous HCl at 1 bar, 25 C.   What chemical reaction occurs and what is the work done during this process?

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so I thought about this:
Zn(s) + 2 HCl  :rarrow: Zn++(aq) + 2 Cl-(aq) + H2(g)

I think v=c, since it is done inside a vessel.  And I think p and t should change, because the mol of gas increase, and v stays the same, so t should increase too, but I'm confused as to what relation I should use to solve this.  Would this be solved with:
w=-nRT ln (P1/P2)  ?

Please help me out with an explanation.  thanks very much!
Title: Re: gas expansion problem
Post by: MrTeo on September 15, 2013, 03:57:24 AM
The reaction is correct.

I think v=c, since it is done inside a vessel.

Is it? I didn't get this from the text, I actually thought it was an expansion against atmospheric pressure.