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Topic: Chemical equilibrium question, it seems simple but i just can't get it right  (Read 3985 times)

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1101

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Chemical equilibrium question, it seems simple but i just can't get it right
« on: August 14, 2009, 04:02:11 PM »
The said question:

Consider the following equilibrium at high temperature:

2H2(g) + S2(g) <--> 2 H2S(g)

Analysis of the contents of a 4.0L flask reveals that there are 5.7 moles of hydrogen gas, 2.4 moles of sulfur gas, and 5.3 moles of hydrogen sulfide gas in the flask at equilibrium. Calculate the equilibrium constant Kc.

Something must be flying way over my head because this question looks incredibly easy. I just find the concentrations of each substance by dividing the given number of moles by 4 and then plug those values into the equilibrium equation.

Anyways here's what i'm doing:

[H2] = 5.7/ 4 = 1.425
[S2] = 2.4/4 = .6
[H2S] = 1.325

and the equilibrium equation

Kc = ([H2S])^2 / ([S2])*([H2])^2

= 1.325^2 / (.6)(1.425^2)
= 1.44

no matter what i try i always seem to get back to 1.44 as being the equilibrium constant, but its not right.

Borek

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Re: Chemical equilibrium question, it seems simple but i just can't get it right
« Reply #1 on: August 14, 2009, 05:27:45 PM »
Why do you think it is wrong?
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1101

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Re: Chemical equilibrium question, it seems simple but i just can't get it right
« Reply #2 on: August 14, 2009, 05:32:25 PM »
It's for a class, i have to input it online and it keeps telling me is the wrong answer (i've already tried scientific notation and everything).

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