# Homework Help: Compare a system to equilibrium

## what are you doing in the summerrr?

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4. ### studying chemistry:my one and only love

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1. May 12, 2007

### oceanflavored

1. The problem statement, all variables and given/known data
Determine whether or not each of the following system is in equilibrium. If the system is not in equilibrium, predict whether it will proceed in the forward or reverse direction:
2 H2(g) + O2(g) ---> 2H2O(g)
and Kc (equilibrium constant) is 9.1 x 10^80
and the concentrations are H2: 3 x 10^-30 M...for O2: 2.2 x 10^-24...for 2H2O: 0.0180 M

2. Relevant equations
To compare a system to equilibrium, you have to compare K to Q. where Q is [products]^coeffecients / [reactants]^coeffecients
and if Q = K, the reaction is at equilibrium...if Q < K, the reaction will move in the forward direction...and if Q > K, the reaction will move in the reverse direction.

3. The attempt at a solution
so i solved it like this...
[0.0180]^2 / [3 x 10^-30]^2[2.2 x 10-24] and i got...1.64 x 10^79 for Q
and since Q < K i said the reaction would move in the forward direction

and here's where the problem comes in :yuck:
the book says: that for Q i should get 9.1 x 10^80, meaning that Q would be equal to K and reaction would be in equilibrium.

please help me. am i inputing the things in my calculator wrong? or is the book wrong? thanks muchhh

Last edited: May 13, 2007
2. May 13, 2007

### oceanflavored

come on guysssssss.
you can do this.
&gracias.

3. May 13, 2007

### hage567

Well, I'm no chemist, but I think your calculation for Q is correct. I can't see a mistake in it. Are you sure you copied everything correctly? Perhaps the book is wrong.

4. May 13, 2007

### oceanflavored

Thanks!

i'm positive i copied everything correctly.&i did it like 10 times.
so the book is probably wrong.
thanks so much hage657 :tongue: