Help understanding this thermodynamic problem
Started by super112
Reversal causes inversion of the numerator and denominator (our "products" are now our reactants, and vice versa). The reduction of the stoichiometric coefficients by half is why the power is halved.
Since the reaction was reversed you take the reciprocal of the equilibrium constant.
Hope this helps.
Dr. Romano
Last edited:
Wasn't it divided by 2 since we are doing it in reverse? So instead of K=2.0 you would do 1/2.0 because originally products/reactants = 2 and now the products (2) are the reactants so products/reactants became 1/2 instead? I thought halving the coefficient makes it to the power of 1/2 not the 1/2.0 part
Please correct me if I'm wrong but I think you meant when the reaction is halved you square root it.
Just remember: K(original) = [Product] / [Reactants]
Thus if the reaction is reversed then the original reactants become products and the original products become reactants: K(reverse) = [Reactants] / [Products]
Mathematically this these equations are the inverse of each other:
K(reverse) = 1/ K(original) ======> 1 / { [Product] / [Reactants] } ===> [Reactants] / [Products]
Say, [Product] = 5
[Reactant] = 1
Koriginal = 5/1 This equals 5...
Now for the reverse
K reverse = 1 /(5/1) ===> 1/5 The inverse of the original.
Use my values and double their concentrations and see whats happens...
Product = 5*2
Reactants = 1*2
K(double) = [10]^2 / [2]^2 == 100/4 == 25 Double the concentration equals K(original) squared! 5 squared is 25
Thus if the reaction is reversed then the original reactants become products and the original products become reactants: K(reverse) = [Reactants] / [Products]
Mathematically this these equations are the inverse of each other:
K(reverse) = 1/ K(original) ======> 1 / { [Product] / [Reactants] } ===> [Reactants] / [Products]
Say, [Product] = 5
[Reactant] = 1
Koriginal = 5/1 This equals 5...
Now for the reverse
K reverse = 1 /(5/1) ===> 1/5 The inverse of the original.
Use my values and double their concentrations and see whats happens...
Product = 5*2
Reactants = 1*2
K(double) = [10]^2 / [2]^2 == 100/4 == 25 Double the concentration equals K(original) squared! 5 squared is 25
Honest mistake..I read the question too quickly...I have corrected my response.
Thanks and keep up the good work..
Dr. Romano
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