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Topic: Trick Question? (Equilibrium problem)  (Read 12237 times)

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Offline trinhn812

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Trick Question? (Equilibrium problem)
« on: January 02, 2008, 08:17:44 PM »
For the reaction    NH3(g) + H2S(g) ↔ NH4HS(s)   

K = 400. at 35.0°C.  If 2.00 mol each of NH3, H2S, and NH4HS are placed in a 5.00-L vessel, what mass of NH4HS will be present at equilibrium?  What is the pressure of H2S at equilibrium?



Since the product is a solid, wouldn't the equation be
K = 0/ [NH3] [ H2S].  Hence I wouldnt have to finish the problem?

or would it just be [NH4HS]/ [NH3] [ H2S]?

Offline LQ43

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Re: Trick Question? (Equilibrium problem)
« Reply #1 on: January 02, 2008, 09:26:44 PM »
Sorry, can't get out of doing the problem

the concentration of a pure solid or liquid in an equilibrium is constant at a given temperature and so becomes part of K,

K = 1/ ([NH3][H2S])

Offline yosh

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Re: Trick Question? (Equilibrium problem)
« Reply #2 on: January 02, 2008, 10:19:34 PM »
First use the ideal gas law to find the total pressures of the gases.  Then use Dalton's law to find out the pressure of H2S.

Offline Borek

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Re: Trick Question? (Equilibrium problem)
« Reply #3 on: January 03, 2008, 03:58:58 AM »
First use the ideal gas law to find the total pressures of the gases.  Then use Dalton's law to find out the pressure of H2S.

No. You have to account for the reaction taking place. LQ43 already hinted in the right direction (no surprise here ;) ).
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Offline LQ43

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Re: Trick Question? (Equilibrium problem)
« Reply #4 on: January 03, 2008, 09:16:43 PM »

 thanks Borek! :)

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