00:01
Here in this problem, 100 grams solution of urea in water has 40 grams urea.
00:06
The molar mass of urea is 60 grams per mole.
00:10
We have to find out the molarity of the urea solution and then we have to find out the mole fraction of urea in the solution.
00:18
Now first we'll find out moles of urea.
00:26
That will be the mass of urea 40 grams divided by the molar mass of urea 60 grams per mole.
00:35
And we get 0 .667 moles.
00:43
Now here given 100 grams of solution of urea in water.
00:50
So we are assuming this water, it is water 100 grams.
00:56
And we'll find out the volume of water.
01:02
Volume of solution, which is basically water, and that we'll be the mass times density.
01:14
Mass is 100 grams and density is, sorry, mass divided by density.
01:27
And here we have mass divided by density 1 gram per milliliter, density of water.
01:37
So we get 100 milliliters.
01:41
We divide by 1000, we get 0 .1 ,000.
01:44
Liters because one liter is thousand milliliters.
01:49
So we can now can calculate the molarity of the solution, that is moles of salute, which is 0 .667 moles divided by volume of solution in liters, this one, 0 .1010 liters...