posted by tracy .
When the concentration of I2 is increased to 1.5 M, the ratio of products to reactants is 28. The equilibrium constant for the reaction is 83. In which direction will the reaction shift to regain equilibrium?
reactants ==> products
K = 83 = (products)/(reactants)
Q = 28 which means products are too small and reactants too large. That's the only way you can get a smaller number than Kc. Reaction must shift to the right.
Actually, you don't need to know Q = 28 to predict the same thing.
reactants = products.
You ADD to make reactants 1.5 M (and nothing else). Therefore, you know that adding reactants will force the equilibrium to the right.