Automobile air bags inflate following a serious impact. The impact triggers the chemical reaction: 2 NaN3(s)¡2 Na(s) + 3 N2( g) If an automobile air bag has a volume of 11.8 L, what mass of NaN3 (in g) is required to fully inflate the air bag upon impact? Assume STP conditions.

Video transcript

Welcome back everyone to another video automobile air bags inflate following a serious impact. The impact triggers the chemical reaction, two moles of sodium azide produce two moles of sodium plus three moles of nitrogen. If an automobile air bag has a volume of 18.2 L, what mass of sodium azide in grams is required to fully inflate, inflate the airbag upon impact assume STP conditions which stands for standard temperature and pressure. So let's solve this problem. And the good news is is that we can actually solve it in a single step. We're starting with an air bag of 18.2 L. Ok. So we have liters of nitrogen. Why? Well, basically when nitrogen is released, it will fill our bag completely. So we have the liters of nitrogen and we can essentially use that information to convert liters of nitrogen into the number of moles. Let's recall that at standard temperature and pressure, one mole of any gas occupies 22.4 L. So we can say that one mole of nitrogen occupies 22.4 L of nitrogen. And using dimensional analysis, we can clearly see that liters cancel out and we end up with moles of nitrogen. OK. So if we are looking for sodium azide, we want to convert the number of moles of nitrogen into the number of moles of sodium azide. And for that purpose, we need to use the balanced chemical equation. Let's notice that there are two moles of sodium azide per three moles of nitrogen. And now we can clearly see that most of nitrogen they cancel each other out and we end up with most of sodium azide. Our final step is to get the mass of sodium azide. And once again, we can use the molar mass. Let's take one mole of nan three. And we know or we can essentially calculate the molar mass of sodium azide as 65.02 g per mole using the periodic table. So in this case, once again, what we notice is that moles cancel each other out and we end up with grams. And the answer that we get is 35.2 g of sodium azide. That would be our final answer to this problem. Let's sleep on it and that will be it for today. Thank you for watching.