00:01
All right, so we have dry ice sublime, and dry ice is carbon dioxide.
00:08
And if we want to know a volume, i'm sorry, a pressure, we may want to use the ideal gas law.
00:16
Pv equals nrt.
00:20
P is pressure, v is volume, n is number of moles, r is the gas constant, t's temperature and kelvin.
00:27
So we're going to have to rearrange this in order to find pressure, divide both sides by v.
00:39
But we're going to have to do some conversions.
00:42
We don't know the number of moles, but we do know the number of grams of carbon dioxide.
00:48
And so the molar mass of carbon dioxide is 44 .01 grams.
00:57
And so that will give us 0 .0273 moles of our carbon dioxide.
01:10
So this is n.
01:13
Now we're also told that we're at 25 degrees c.
01:19
We have to make that kelvin, so we have to add 273, 298 kelvin is our temperature.
01:34
0 .821 liter atmospheres over mole kelvin is r, but you have your pressure in millimeters of mercury.
01:47
So we have to convert r into millimeters of mercury.
01:53
There's 760 millimeters of mercury in one atmosphere.
01:58
So that winds up giving us our value of r to be 62...