00:01
What is the number of molecules per cubic meter for this problem? so for part a, we're given our initial temperature is 20 degrees celsius, so 20 plus 273, gives us 293 kelvin, and we're also given our pressure.
00:17
Now, we can use our initial relation pv is equal to nrt.
00:23
N is our number of moles is pv over rt.
00:26
So we can plug in our 1 atm, which is 1 .01 times 10 to the 5 pascels, times our volume, which is 1 meters cubed, divided by 8 .314 times our temperature of 293 kelvin.
00:43
So now let's plug this into a calculator.
00:46
1 .01 times 10 to the 5 times 1, divided by 8 .314 times 293 gives us 41 .46 as our number of moles.
00:58
But we want our number of moles in a molecule, so we multiply this by avogadro's number, 6 .02 times 10 to the 23.
01:09
So we take our 41 .46 times 6 .02 times 10 to the 23, and we get 2 .49 times 10 to the 25 molecules for part a.
01:20
Now for b, what's the mass of one cubic meter of this error? so we want to assume a certain distribution...