Determining the Reaction Quotient

Jules Bruno
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Hey, guys. So here, if we take a look at this example, it says for the following reaction are equilibrium. Constant is equal to 25. Now. They tell us at a particular time the following concentrations are measured for the given compounds. So each one of these compounds is giving a new concentration, and they're asking us which of the following statements is true. Realize that here they're talking about the amounts of each one of these compounds either increasing or decreasing. And the only way we could know this for sure if it's increasing or decreasing, is to know which way is my reaction shifting. It's shifting towards the product side or the react inside. So what this question is really asking us to do? It's to do Q versus K. Remember. Q. Is your reaction quotient it's used to determine? Are we at equilibrium when Cuba is equal to K were at equilibrium and there will be no shifting, So just like equilibrium, constant Q. Is equal toe products overreact? It's and just like a it ignores solids and liquids. Everything here is a gas, so we're going to keep them around. So we have NH three remember, the coefficient becomes the power. There's a two here, so this is squared. Divided by H two. There's a three year. So this is cube Times end to So What we do now is we're gonna input each of the values for each one of these compounds and federal Q. It's so NH three here is 1.50 times 10 to the negative, too, which is going to be squared, divided by H two, which is 2.25 times 10 to the negative. Six cube times 3.30 times 10 to the negative one. When we punch all that in, it's gonna give us as an answer 5.9 nine times 10 to the 13. Now that we have Q, we can compare it to K to determine which way will our equation shift. So remember K is 25. Que was to the 10 to the 13th Powers. What's much larger? Remember, case what we wanna be? We wanna be an equilibrium. So which way will queue shift? To get to K, you will have to shift to the left so it's gonna go in the reverse direction, which means in our equation. It also goes on the left or reverse direction. Remember, whichever way you're heading will be increasing. And if this side is increasing, the other side has to be decreasing. So now let's see. We're looking for what's true. H two will increase. Yes, that's true because we're heading towards its side here. The equilibrium constant will increase. The only variable that we can use to increase or decrease K is heat. He does not being added or removed, so okay will not change. The concentration of NH three will increase. Now it's decreasing. The concentration of end to will decrease. No, it's increasing. No change will occur only if we're at equilibrium. If Q was equal to K, which we saw that they're not equal, so it does not work. Now that we've seen this, we'll move on to the second example question. You could take a look ahead and see if you can figure it out. If not, don't worry. Just come back and take a look at how I attempt to do this question.