 Okay, guys, so stop me if you have any questions while we're going over this problem, but anyways, so But let me read it to you It says the reaction used in the deployment of automobile airbags is the high temperature decomposition of sodium azide And a M3 It's a solid to produce nitrogen. So that's actually what's in your In your car, you know before You get into an accident right and then then this this equation happens But anyways, it's just to produce nitrogen gas According to the following equation and the nitrogen gas is what actually blows up the air bag The equation is this chemical equation. So two sodium azide solid goes to two Sodium solid Plus three nitrogen gas Um What volume and liters of nitrogen gas at a final pressure and temperature of? 1.15 ATM, so let's write these things down. So we're looking for the volume The pressure 1.15 ATM So that's cool. So it's already in the units that you're gonna want it in and 30 0.0 degrees Celsius So of course remember we're gonna have to change that to kelvin, right? So when we do that 273.1 That's gonna equal 303.1 Okay Respectively, would you expect to be produced by the decomposition of 45 grams of sodium azide? So it gives you the mass of sodium azide 45.0 grams And Remember grams is not really as useful in chemistry We need to Make it into moles because that gives us an actual value of the number of units of molecules that we have Okay, so I calculated the Molar mass of sodium azide before this problem, so let me just put it in Calculated it to be 65.01 grams The molar mass of sodium azide So remember we need to cancel out grams and we need moles so we're gonna put moles on top Grams on the bottom use that as our conversion factor, right? So 65.01 Grams or one mole grams cancel and of course that's grams of sodium azide. So let's do this problem So we're actually So zero point and we'll just do it to a few sig figs out At the end Cut it down to the three sig figs Okay, so that's how many moles of sodium azide. We're starting with, okay so we want to know the Volume of nitrogen gas, so how do we do volume? Well we don't really have a Way to do it with those things, but we remember the equation PV equals nRT Okay, and you guys know stoichiometry from the last chapter. We've done stoichiometry before okay, so what we can do is Put those PV equals nRT, which we learned earlier in this chapter and the stoichiometry stuff which we learned from the last chapter together and Figure it all out. Okay, so we know the man or the this is now the number of moles of sodium azide All right, so zero point six nine two two moles Okay, and we're looking for The number of moles of nitrogen. Okay, so what do we know about that that there's a ratio of two to three To the of sodium azide to nitrogen and the number of moles right because the chemical equation tells you the number of moles so Let's go ahead and figure out the number of moles of nitrogen that we've got Okay, so the number of moles of nitrogen that we've got is going to be zero point six nine two two moles Times and that's here. Let's do it this way. So it'll be more clear So this is going to be moles of what sodium azide right? times And what did we say our conversion factor was? a two to three conversion factors so for every two and a And threes we have three and twos remember you can use these as kind of conversion factors so So for want to put two moles And a and three at the bottom Three moles And two at the top notice moles Cancel cancel and all we got to do is so I have one of these calculators that will keep my answer in there So I'm just going to answer times three divided by two And I get this answer so zero point or one point zero Three eight will take it to so that's the number of moles of nitrogen Okay, so now we know the number of moles of nitrogen We know the pressure of nitrogen. We know the temperature of nitrogen so pressure number of moles Temperature you know are that's given to you always so Now we should be able to figure out the volume right and what'll happen is everything will cancel out So you guys getting this thing does it make sense? Okay? Remember you need to write it all down, you know because what did I read this this morning? It's like watching me do chemistry and expecting you to learn chemistry is like watching What do you say? aerobics instructor do aerobics and expecting yourself to lose weight, you know, so anyways, so let's just Isolate the variable that we want right so we want V isolated so we'll divide both sides by P Cancel cancel so what do we have? V equals in RT Over P so that's what we're going to use okay So let me write This number of moles of nitrogen Way down here at the bottom. So hopefully those of you are watching this in the video can still see this Okay, and well I'm gonna erase all of this stuff because of course I'm gonna need this part of the property board And we'll use this equation Okay, so the volume of nitrogen is gonna be the number of moles of nitrogen Times R times the temperature of nitrogen over the pressure and so let's just plug in chug now. So number of moles 1.038 moles So our remember it's given to you But it's given to you in that like text message 0.0 Leaders ATM Over 1 mole Kelp so remember that's the way I like to write it so we can cancel things out And then we got the temperature here 303.15 Kelvin and divide all that by the pressure and remember what I told you before if you can't remember What the units are supposed to be by this time you better remember, but if you somehow just blank on the test or something just remember what the units of the Gas constant is and that'll tell you the units that you want to put all your other things in okay So watch moles cancel there right Kelvin's cancel there. So 1 over is 1 over right? So 18 will cancel there and what are we left with is leaders? So and that's what we wanted because it asks. What's the volume of nitrogen in leaders? So let's do it so times 0.0821 Enter times 303.15 divided by 1.15 So what did I get? 22.47 22.47 leaders is 22.5 Leaders because we got three there three there, so the volume of nitrogen is going to be 22.5 leaders When your airbag goes off, so Enormously huge if you think about that right, but that's good because you want your head to ricochet off of something That's bouncy instead of that So are there any questions about that one you guys if I put this on the test you should be able to get it right? Okay, or something similar because it's not gonna be exactly this problem Leave much more exciting problem than an airbag deploying if you can imagine okay