00:02
Hey there, in this question we are trying to determine pressure when we are given volume, number of grams of a gas, and its temperature.
00:12
Well, this is an ideal gas law problem because the ideal gas law gives us pressure times volume is equal to the number of moles.
00:27
Well, we have mass but we can use molar mass to calculate moles times universal gas constant r multiplied times temperature in kelvin.
00:37
Alright, so if we rearrange this equation to solve for pressure, what we need to do is divide both sides by volume.
00:46
That tells us that pressure is equal to nrt, number of moles times universal gas constant times temperature, divided by the volume.
00:58
Alright, let's list out each of these variables here and determine the value that we need to use.
01:07
Alright, so we want the pressure in atmospheres.
01:14
So what i'm going to do is select my r first.
01:17
The one that has its pressure units of atmospheres is 0 .0821 liters times atmospheres over mole times kelvin.
01:31
Alright, going, just going on down then, our temperature we are told is 25 degrees celsius, but that has to be in kelvin.
01:39
So we can convert it to kelvin by, not by doing dimensional analysis, but by adding 273.
01:48
Anytime we're converting celsius to kelvin, we need to add 273.
01:52
That gives us 298 kelvin.
01:56
Our volume is already in liters, so that is good.
02:00
That matches up with our universal gas constant which is in liters.
02:05
Alright, so the only thing we have left to figure out is our number of moles.
02:08
Well, we have 8 .20 grams of nitrogen.
02:13
To convert that to moles, we need to use nitrogen's molar mass...