00:01
So in this problem, we have one liter of liquid nitrogen in a one by one by two meter room.
00:09
And we want to figure out how much air in that room is displaced when this amount of nitrogen evaporates.
00:16
And so to do that, we want to find the volume of the nitrogen and the volume of the room, and then just divide the volume of nitrogen by the volume of the room to get what percentage of that is now nitrogen.
00:28
And so the first thing we want to do is convert this one liter of liquid nitrogen into number of moles so that we can use the ideal gas law to find the volume of nitrogen gas.
00:42
And so the first conversion here is just converting one liter into milliliters.
00:47
So a thousand milliliters in one liter.
00:51
Then we want to multiply by the density given, which is 0 .807 grams per milliliter.
01:00
And now that we have grams, milliliters have cancelled and liters have cancelled, we can divide by the molar mass of n2, which is 28 .0 grams per mole.
01:15
And so now our final answer will be in moles, which is equal to 28 .82 moles.
01:26
So now we want to use the ideal gas law, and so i'll go to a new page here.
01:30
So pv equals nrt.
01:34
And we want to rearrange to solve for volume.
01:37
So volume equals nrt over p.
01:42
Our n, we just calculated to be 28 .82 moles.
01:51
Our r value is 0 .082 -057...