 Okay, so I'll just show this one again. Let's calculate the concentration of hydrogen sulfide. If we know all of this information and that the equilibrium expression is this shown, okay? So the first thing you're going to need to do is calculate the KVQ. That's going to be the products over the reactants. In this case, SH2, concentration of SH2. Since there's a tube in front of that, we're going to put a square there. So the coefficient equals the superscript. Then you're going to multiply that or divide that by the reactants, which is the concentration of SH2 times the concentration of H2. And again with the coefficient being 2, you want to square that. So now we're looking for the concentration of SH2. So we're going to have them algebraically manipulate this equation. So you want to isolate the variable SH2 together. So that variable there. You want to get rid of all of this stuff from the bottom, put it over here, and you want to get rid of that square, okay? So the first thing you could do, ideally, would be to get rid of the S2 concentration. So if we multiply both sides by S2, which is the concentration of S2, that cancels out the concentration of S2 there. And now we have new expression, concentration of S2 times gay DQ equals the concentration of SH2 squared divided by the concentration of H2 squared. Now what we could do is to get rid of H2 squared, multiply both sides by the H2 squared. We'll cancel out the H2 squared. I want to get that expression there. So now let's just turn this around so we can use that. So SH2 squared now equals the concentration of H2 squared times the concentration of S2 times the gay DQ. So to get rid of the square root, you've got to take the square, I mean to get rid of the square, you've got to take the square root of both sides. So that will get rid of the square root, square in the square root, and so we get, oh, the new expression is that one, okay? So now all we've got to do is take these numbers here and plug them into this equation here. So the concentration of SH2 equals the square root of the hydrogen and ion concentration in the square, which is 2.1 times 10 to the negative 1 squared times the sulfur concentration, 1.1 times 10 to the negative 6. Notice I'm not using any units in this because they won't work out to be just mold, which is what we wanted to do. KEQ is going to be 1.1 times 10 to the 7. And the order of operations you want to do this in is you're going to want to take 2.1 times 10 to the negative 1, square that first. Then you're going to want to multiply that by 1.1 times 10 to the negative 6. Then you're going to want to multiply that times 1.1 times 10 to the 7. And when you do that, all of that, you're going to get this number, 0.73. And you've got to remember that since this is in brackets, that it means mold or concentration. So it's going to be 7.73 mold. And again, if you wanted to put that 7.3 times 10 to the negative 1, all of that, you're okay in doing that. That's your final answer. Hopefully that makes sense.