00:01
First let's write down the van der waals equation p plus a n square divided by p square multiplied by p minus n, p is equal to nr.
00:14
Now let's find the units of a and p.
00:17
We know that the units of pressure are atm, the units of volume are liquid, the units of n are mole and the units of r are atm liter per mole kelvin.
00:29
The units of temperature are kelvin.
00:31
For a we can look the term a n square divided by b square.
00:35
This term must have the same units as pressure since it is added to p.
00:41
Therefore the units of a are atm liter square divided by mole square.
00:50
For b we look the term b minus nb.
00:54
This term must have the same units as volume.
00:58
Since it is multiplied by p therefore the units of b are liquid per mole.
01:06
Now let's use the van der waals equation to calculate the pressure of a sample of ammonia at 220 degree celsius with a molar volume of 2 .89 liters per mole...