00:01
We begin this question by calculating the number of moles of water in one liter.
00:06
The number of moles can be calculated as follows.
00:09
It is equal to the total mass divided by the mass of one mole.
00:15
Let me call this the molar mass of water.
00:19
Then, we can calculate the mass of water using the density.
00:23
Roughly, the mass is equal to the density times the volume.
00:27
The density of water is 1 kilogram per liter, and the volume that we have is 1 liter.
00:34
Therefore, the mass is 1 kilogram.
00:36
And now we calculate the molar mass of water.
00:40
The molar mass of water is given by 2 times the molar mass of hydrogen plus the molar mass of oxygen.
00:51
Then we have 2 times 1 plus 16, and this is 18.
00:57
Grams per mole.
00:59
This is the molar mass of water.
01:02
Therefore, the number of moles in one kilogram is given by one kilogram divided by 18 grams, but we can't have kilograms up here and grams down here...