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When 0.600 atm of NO­­2 was allowed to come to equilibrium the total pressure was 0.875 atm

Jules Bruno
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Hey, guys, In this brand new video, we're gonna continue with our conversation on calculating equilibrium Concentrations. So let's take a look at this particular question we're gonna say when 0. atmospheres of n 02 was allowed to come to equilibrium, the total pressure was 20.875 atmospheres calculate the KP of the reaction. Now all I'm giving you is 0.600 atmospheres of Eno to I'm saying I'm allowed me to come to equilibrium. What that tells me is this amount is not my equilibrium amount. It's rather my initial amount. So this is my initial pressure. So all we say to ourselves is Do we have to use a nice chart? And the answer here is Yes, because we're gonna have this missing equilibrium amount. This is missing equilibrium amount, and this is missing an equilibrium amount. Any time. More than one of my compounds in my balanced equation is missing an equilibrium amount. I have to do a nice chart. This number here I'm giving it time to get to equilibrium, which means it's my initial pressure. So we're gonna say I is initial. See, it's change. E is equilibrium. So we're gonna say Initially, we're starting out with 0.600 atmospheres. Remember Atmospheres Goals with KP. I don't tell us anything about N. O or 02 so they're initially at zero. Remember the important phrase we've been saying? We're losing reactant to make products. So this is going to be minus two X because of the two and it's minus because it's reacted. Plus two x the two there. That's why it's plus two x plus x Bring down everything. 0.600 minus two X plus two X plus X. Now what we should realize here is they're telling me what the total pressure is now this goes back to Henry's law or actually not Henry's Law. But more importantly, Dalton's law Dalton's Law says that the total pressure that we experience is equal to the pressure of all of the gas is added up. So my total pressure is equal to the pressure of n 02 plus the pressure of Eno plus the pressure of +02 and at equilibrium. That's my equilibrium. Total pressure. So what we're gonna do here is say, at equilibrium. Each of these gasses is equal Thio Each of these equations. So at equilibrium are total pressures. 0.875 atmospheres at equilibrium N 02 is 20.600 minus two x at equilibrium. Eno is two x at equilibrium. 02 was just X. We're going to say that this negative to in this positive to basically cancel each other out. So our equation becomes 0. atmospheres equals 0.600 plus X. We need to isolate X here, so we're gonna subtract 0.600 0.600. So x here equals 0.275 atmospheres. Remember, this is Dalton's law. The total pressure we experience is the pressure from all of the gas is added up together. And this is this an equilibrium, total pressure. We use the equilibrium equations for each of the compounds we just isolated. What? Exes. So all we need to do is take this X answer, plug it in here, plug it in here, plug it in here and we'll know each of them at equilibrium. And if we know each of them at equilibrium, then it's those equilibrium amounts that we plug into KP. Remember, KP is just products overreacting. So it's Enel squared times out to divided by N 02 squared because the two on the two here. So when we plug in the X in for N we get 0.50 atmospheres when we plug it in for N o at equilibrium and ah equals two x plug in the X. And so we just found. So that's a no. And then 02 is just equal to exit equilibrium. So with that same exact number now take all those numbers and plug it in. Okay? And when you do all that, you'll get your KP equal to 33. Now, to do this question, you had to have a knowledge off Dalton's law. Remember that deals with gasses and then apply that concept to this new idea of a nice chart. So it's kind of taking a little bit of old information, combining with some new information in order to obtain R K P value