List the following aqueous solutions in order of increasing boiling point: 0.120 m glucose, 0.05

List the following aqueous solutions in order of increasing...

Key Concepts

Colligative Properties

Colligative properties are characteristics of a solution that depend on the number of solute particles present rather than on the identity of the solute. These properties include boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure, and they are useful for understanding how solute particles affect the physical properties of solvents.

Boiling Point Elevation

Boiling point elevation is a colligative property where the boiling point of a solvent increases when a non-volatile solute is dissolved in it. This increase is directly proportional to the molal concentration of the solute particles and the boiling point elevation constant, reflecting the fact that more solute particles cause a greater disruption of the solvent's ability to vaporize.

Molality

Molality is a concentration unit defined as the number of moles of solute per kilogram of solvent. It is particularly useful in colligative property calculations because it does not change with temperature, ensuring that the concentration value remains constant despite thermal variations.

van't Hoff Factor

The van't Hoff factor is a dimensionless quantity that represents the number of discrete particles produced in solution per formula unit of solute. It is critical in colligative property calculations because electrolytes, which dissociate into ions, effectively increase the concentration of particles, thereby enhancing the boiling point elevation effect relative to non-dissociating solutes.

Transcript

00:01 Okay, problem 71, we have three different equate solutions, and each would contain these three different solutes dissolve in it.

00:08 Okay, so each of these will change the boiling point of water differently.

00:13 So we're just going to arrange the equate solutions in increasing boiling point.

00:19 Okay.

00:20 So we're starting with glucose.

00:22 Glucose, once you dissolve it in water, it doesn't really dissociate into different components.

00:28 It just stays as glucose.

00:31 So glucose particles just kind of dissolved in water.

00:37 For lithium bromide, however, it dissociates into a lithium ion, right, in a bromide.

00:48 So each of these, according to our information, would be 0 .050m.

00:54 1 .050 for each, okay? so that would give us a total of 0 .10m.

01:07 Okay, so we just add these.

01:11 And for zinc nitrate, okay, zn, no3, 2, that would dissociate to zinc ion, okay, zn2 plus, and no3 minus.

01:26 Okay, no3 minus.

01:30 But as you notice no3 has a subscript of two so that means there's going to be two nitrate ions for each zinc ion that we get okay and again just like lithium bromide each of those would be 0 .050 5 .0 .0 .050 okay so we're just adding all these three which gives us a total of 0 .1 5 -0m okay and then at this point we're using the boiling point elevation constant for water so kb for water right kb equals 0 .512 degrees celsius per m okay so in order to get the boiling point elevation of water we take this kb and we multiply it by the molality that we get after dissociating in water.

02:44 Okay.

02:45 So again for glucose, for glucose, that's just 0 .1 to 0.

02:49 It doesn't dissociate further.

02:52 So for glucose, let's do it over here, okay.

03:03 So for glucose, again, we just multiply that kb, multiply that kb, and the molality...

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