00:03
Let's solve for the mass percent of palmetic acid and the stearic acid sample, given the information given.
00:10
So we can calculate from the information given, delta tf.
00:14
We're told that the freezing point of the solution, it is 5 .072 degrees celsius, and the freezing point of the solvent is 5 .533 degrees celsius.
00:28
So delta tf will work out to minus 0 .461 .1.
00:33
Degrees celsius.
00:37
Knowing delta tf, we can calculate the molality using this formula here, negative, minus .461 degrees celsius minus the constant here is going to be 5 .12 degrees celsius per moleal and we'll solve for the molality here.
00:58
So the molality will work out to point 0900.
01:05
So we're told that the solution contains 50 milliliters of benzene and we're given its density.
01:13
So let's solve for the mass of benzene.
01:23
So starting with 50 milliliters times the density.
01:28
0 .879 grams per milliliter.
01:31
Density given for benzene.
01:32
This will work out to 43 .9 grams or converted to kilogram.
01:42
0 .0439 kilograms.
01:44
We'll need this in kilograms as we bring in our molality.
01:50
So we can calculate the moles of the solute, which would be equal to the molality, 0 .0900 moles of the solute.
02:05
The solute would be the mixture of palmetic and stearic acids.
02:12
It's dissolved in benzene, so per kilogram benzene, times the mass of benzene.
02:19
0 .0439 kilograms of benzene will cancel, and this would leave us with 0 .00395 moles of the solute.
02:35
So the moles of solute is the mixture.
02:40
So the total mass is given as the total mass for the mixture is given as 1 .15 grams.
02:56
So let's let the mass of let mass of stearic acid equal to x and the mass of pulmonary.
03:20
Acid equal to y, therefore combining these together, x plus y would be equal to 1 .115 grams...