The Ideal Gas Law Example 2

Jules Bruno
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here in this example question. It says how many moles of ammonia are contained in 25 liter tank at 190 degrees Celsius and 5.20 atmospheres. All right, so they're asking me to find moles of ammonia, so that would be my end Variable. They're giving me leaders. So that would be volume. They're giving me degrees Celsius, which is temperature, and they're giving me atmospheres, which is a unit for pressure. We can see that we have PV and Mt. So we have the ideal gas law to deal with and the variable that's missing, the one that we're looking for is moles. So all we have to do here is isolate moles. So divide both sides here by rt. And then we're gonna say here that moles equals P V over R T. Pressure is on writing atmosphere, So no need to convert. Then we're gonna have here volume which is already in leaders. So no need to convert. Then we have our our constant remember is 0.8 to And now that we know that we're using the ideal gas law, we have to use the units of leaders Times, atmospheres over moles times k temperature, Remember, has to be in Kelvin, so there is a little bit of converting here necessary. So we have 190 degrees Celsius. So add to 73.15 to that, and that will give us 4. 63.15. Calvin. So take those and plug it in 4. 63.15 Kelvin. So what cancels out atmospheres? Cancel out leaders, Cancel out Calvin's cancel out and you'll see that the only unit left are the moles that we need to find. So we're going to get initially 342050 moles. If we look back on the question, this has 366 to sig figs, three sig figs. We go with the least number of sick fix. So we're gonna put our answer asked 3.4 moles of ammonia. So this would be our final answer. So just realize, what variables are you being given? What's the missing variable? Just use your algebra skills toe. Isolate that one very variable and you'll get your answer at the end