00:01
So here they're giving us a conditions of this physics classroom and we need to find the number of molecules in the classroom, the number of molecules per cubic meter, and then the mass of the air inside the room.
00:18
So we have our givens p equals one atmosphere and then t equals 27 degrees celsius.
00:28
We're going to add 273 in order to convert this into so we'll have 3 ,300 kelvin.
00:35
We have the volume of this room is 216 meters cubed.
00:40
And this is going to become 2 .16 times 10 to the 5th liters.
00:47
So we're dealing with an atmosphere.
00:49
So we should convert our meters cubed into liters.
00:52
And we know that there are 1 ,000 liters in every cubic meter.
01:01
So that's how we got that conversion there.
01:05
And then we need to find out moles.
01:08
So first we should find out the number of moles that we have.
01:13
So we have pv equals n rt.
01:15
We can just simply solve for n.
01:18
So n is going to be equal to pv over rt.
01:21
And then we can substitute.
01:25
So one atmosphere 2 .16 times 10 to the 5 liters.
01:33
And then our ideal gas constant that we'll be using.
01:36
We're dealing with liters and atmospheres, so we're going to use 0 .8 .0, rather.
01:51
So that would be 0 .0826 times our temperature of 300.
01:59
This is going to be give us n equals 8 ,776 .1 mole approximately.
02:09
And now we have everything we need to answer all these parts.
02:13
So part a, it's asking us for the total number of molecules.
02:16
So n, we can define as a total number of molecules, and it's going to be equal to the number of moles times avagos number.
02:24
So it's going to be 8776 .1 mole.
02:28
And then for every mole, there are 6 .023 times 10 to the 23 molecules...