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# Solubility and Intermolecular Forces

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Sections
Solutions
Solubility and Intermolecular Forces
Solutions: Mass Percent
Percent Concentrations
Molarity
Osmolarity
Parts per Million (ppm)
Solubility: Temperature Effect
Intro to Henry's Law
Henry's Law Calculations
Dilutions
Solution Stoichiometry
Electrolytes (Simplified)
Equivalents
Molality
The Colligative Properties
Boiling Point Elevation
Freezing Point Depression
Osmosis
Osmotic Pressure

Solubility deals with the dissolving of a solute in a solvent in order to create a solution.

###### Solubility and the Intermolecular Forcess

Concept #1: Understanding the Theory of "Likes" dissolve "Likes"

Transcript

Why was it so important that we identify a compound as polar or nonpolar? Because we're going to say that compounds with the same intermolecular force, or polarity, will dissolve into each other to form a solution. Now we're going to say that if you have a polar and a polar, they're going to mix together well. If you have a non-polar and a polar, their polarities are different, so they won't be able to dissolve into each other to form a solution.
We're going to say according to the theory of likes dissolve likes, basically, the two compounds have to have the same intermolecular force. If they have the same intermolecular force, they have the same polarity. But they could also have different intermolecular forces.
Let's say one compound had hydrogen bonding and the other one had dipole-dipole, that's okay because hydrogen bonding and dipole-dipole are both polar forces. Because they're both still polar, they'll be able to dissolve with one another. But let's say one had dipole-dipole and the other one had London-dispersion. Dipole-dipole is polar. London-dispersion is non-polar. Because of their differences in polarity, they will not mix.
Also, we're going to say that there's a difference between a mixture and a solution. We're going to say mixtures, we've talked about this so many weeks ago, mixtures come in two types. We have homogeneous or heterogeneous. We're going to say homogeneous mixtures mix together. They dissolve into each other. We're going to say that heterogeneous mixtures do not mix.
Oil and water is a good example that we've talked about. They won't mix because why? Oils are non-polar solvents. They're non-polar. Water, on the other hand, is polar. As a result, polar and non-polar do not mix. That's why oil and water don't mix together at all. Mixtures come in these two types.
A solution, all solutions, are just homogeneous mixtures. Remember the difference. Mixtures come in two types. They can either be homogeneous, where they mix together, or heterogeneous, where they don't. All solutions are just homogeneous mixtures. In a solution, we can dissolve both things into each other, so they do mix.

In order for a solvent to dissolve a solute both components have similar polarities.

Example #1: Identify the intermolecular forces present in both the solute and the solvent, and predict whether a solution will form between the two.

CCl4 and P4

Example #2: Identify the intermolecular forces present in both the solute and the solvent, and predict whether a solution will form between the two.

CH3OH and C6H6

Example #3: Identify the intermolecular forces present in both the solute and the solvent, and predict whether a solution will form between the two.

C6H5CH2NH2 and HF

Example #4: Identify the intermolecular forces present in both the solute and the solvent, and predict whether a solution will form between the two.

IF4­ -   and NH3

Practice: Which of the following statements is/are true?

a) Methane will dissolve completely in acetone, CH3COCH3.

b) Hydrofluoric acid (HF) will form a heterogeneous mixture with tetrachloride, CCl4.

c) Pentane will form a homogeneous mixture with CBr4.

d) Methanethiol (CH3SH) is miscible in fluoromethane (CH3F).