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back to Kinetics and Equilibrium links Writing the Equilibrium Expression (mass action equation)
What does K imply? Large K > 1 products are "favored", the equilibrium lies to the right K = 1 neither reactants nor products are favored Small K < 1 reactants are "favored", the equilibrium lies to the left
How do we calculate K when given concentrations?
Calculate the equilibrium constant (K_{eq}) for the following reaction: H_{2} + I_{2} <==> 2 HI
The first thing to do is write the equilibrium expression for the reaction as written in the problem. This is what to write: Now, all you have to do is substitute numbers into the problem. K_{eq} is what we want to find, so that's our "x." Here is what we get:
K_{eq}= 60.2 Solving this and rounding to the correct number of sig figs (remember those??), we get 60.2
How do we calculate K when given Moles and Liters?
Another Calculation At a certain temperature, the equilibrium mixture of PCl_{5} , PCl_{3} , and Cl_{2} has the following concentrations: [PCl_{3}] = 0.035 M, [PCl_{5}] = 0.017 M, [Cl_{2}] = 0.074 M Calculate K_{c} for the reaction PCl_{3(g)} + Cl_{2(g)} <> PCl_{5(g)}
