00:02
In there, in this question, we are dealing with the colligative property of boiling point elevation.
00:08
So boiling points are increased when we add a solute to a solvent, making the new boiling point, whatever the original or normal boiling point is, plus that change in the boiling point.
00:27
And to calculate how much the boiling point changes, we need to take the equation, change in boiling point, that greek letter sign, or greek, sign delta means change in, and it's equal to kb, which is the boiling constant for the solvent, multiplied by the molality.
00:48
Since our solute here is molecular, we don't have to worry about the vantorff factor because molecules do not break into ions when placed in solution.
00:56
Okay, so we're given our kb here.
00:59
We're told the kb is 1 .22 degrees celsius per molow.
01:06
But we do need to calculate the molality.
01:10
Malality is defined as moles of solute per kilogram of solvent.
01:22
Well, we are given the mass of our solute.
01:24
We are told it's 85 .0 grams.
01:36
And this is of our sugar solution.
01:43
And it is dissolved in 500 grams of the ethanol.
01:52
Okay, so our numerator needs to be in moles.
01:54
To do that, we use the molar mass.
01:58
In one mole of the sugar, we are given the molar mass in the problem.
02:02
We are told it is 342 .34.
02:10
I need that in the denominator because i want the grams of sugar to cancel.
02:15
So now i have moles in the numerator, which is what i need.
02:19
And now i need to focus on the denominator, because that is in grams right now.
02:24
Well, 1 ,000 grams are in every kilogram...