00:01
All right, so we're told that four moles of each of these reactants is placed in a one liter container, so that's four molar, is our starting concentration of each.
00:12
And we initially have zero of the product.
00:15
And we want to know what are the final concentrations when we reach equilibrium.
00:22
So we're going to have some amount of each of these species reacting, and we don't know what that is.
00:27
So we'll just call it minus x and minus x.
00:28
And then because there's a two here twice as much, product will form for every amount of reactant that reacts.
00:37
So then we're left with 4 minus x, 4 minus x, and 0 plus 2x, which is 2x, and these are molarities.
00:45
And we know that the equilibrium constant expression is going to be the product squared because of the coefficient.
00:53
And then we have each of the reactants raised to the first power, like so.
01:02
And then we can plug in.
01:04
So this is going to be 2x squared, and this is 4 minus x times 4 minus x, so just 4 minus x squared.
01:13
And we're told that it's equal to 0 .1.
01:16
So they're both squared, so conveniently we could just go ahead and take the square root of both of these.
01:22
Square root of 0 .1, you can do it on your calculator, 0 .36.
01:30
I won't round off yet.
01:31
And that's equal to 2x over 4 minus x...