00:01
To determine the molar concentration of water after the second equilibrium is reached, we first need to calculate the equilibrium constant for this reaction.
00:09
To do that, we'll take the information provided the initial concentrations of h2s and s02 and a final concentration of water.
00:19
The kc expression, excluding the solid, will be the concentration of water squared divided by the concentration of h2s squared and the concentration of s2 in the, denominator.
00:33
With initial concentrations of 0 .5 and nothing of the products, when equilibrium is reached, this will decrease by 2x with its 2 coefficient, this will decrease by x and this will increase by 2x.
00:48
So we need to put a 2 on this right here.
00:52
Then at equilibrium, these will be our equilibrium concentrations.
00:57
They tell us that the concentration of h2o, which is 2x, is equal to 1 .3 times 10 to negative 3, this allows us to calculate x, which will be .00065.
01:13
Knowing x, we can go back and calculate these equilibrium concentrations and then plug all of the concentrations into the kc expression to calculate kc, and the equilibrium constant is 1 .36 times 10 to the negative 5...