00:01
So you're looking at this sample here that has 215 tor of n2, 102 tor of o2, and 117 tor of h .e.
00:09
So the total pressure of the mixture is this equal to the sum of the partial pressures, right? so it just equals 215 plus 102 plus 117.
00:29
434 tor.
00:35
Okay.
00:36
And so to find the mass of each gas present, we are looking at a 1 .3 liter sample or 1 .35 liter sample at 25 degrees celsius.
00:56
So we can just use the ideal gas law to find the number of total moles of gas first.
01:03
Right.
01:05
So we know the total pressure is 434 tor.
01:18
There's 1 .35 liters.
01:21
There's n moles and the ideal gas constant we want to use since we're given it in tours, we would want to use 62 .36.
01:46
Okay, and this is in liter tours per kelvin per mole.
01:54
And then the temperature is going to be 298 .2 kelvin.
02:00
So the total number of moles of this gas is going to be 62 .36 times 298 .2.
02:08
And then take 434 divided by that.
02:16
And so in total you have 0 .0 .315 moles of gas.
02:27
And so now you just multiply by the mole fraction of each times 215 over 434 is 0 .0156 moles of n2, which corresponds to roughly 0 .4.
02:59
437 grams of n2.
03:06
You can do the same thing for oxygen...