Equilibrium Constnant Discrepancy: SO2 + O2 -> Kc = 279

[nhrock3]

we put 64 grams of SO2 and 32 grams of oxygen
it reaches equilibrium in 1000k
what is the equlibrium constnant
$$\frac{(\frac{0.85}{5})^2}{(\frac{1}{5})^2\frac{1}{5}}=3.61$$

but the book says 279
why
?

 

[Borek]

Is this whole question? I am sure it is not, I am sure there were more information provided that could be used to calculate final amounts of all three gases.

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[nhrock3]

you are correct i forgot to mention the formula
2SO2+O2=2SO3
and we put 0.85 moles of SO3

 

[Borek]

This is probably still not all or you are not quoting the information properly. So far you have listed substances that were put into the mixture, I believe these amounts are not what was present at equilibrium.

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methods

 

[nhrock3]

i forgot to mention that this whole thing in 5 litter container

 

[Borek]

And this is probably still not all. If the mixture was left to react till it reached equilibrium, final concentrations are not the initial ones. So far you have listed what was put into the container - that's not enough to calculate final concentrations.

Any other information you have forgot to mention?

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[nhrock3]

sorrry again
in the end we find 0.85 moles of SO3

 

[Borek]

You won't get much more from me: use stoichiometry to calculate how much sulfur dioxide and oxygen were left, then use these values to calculate concentrations (or partial pressures) of all gases.

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