Monday, April 4, 2011

Lecture #2 Wednesday, March 30th

Ksp was introduced and we discussed the similarities/differences between solubility in terms of the amount (in grams) that dissolves per liter of solution, the molar solubility, and the Ksp.

First we need to define what we mean by solubility and we need to consider what we already know about solubility and compare that to what a chemist thinks about when they hear the term solubility.

Overview of Solubility

When chemists discuss solubility they do so in terms of the solubility product constant.

The Solubility Product Constant

Example Problem: 1.4 x 10-6 grams of ZnCO3 dissolve in 1.000 mL of solution and 2.8 x 10-6 grams of BaCrO4 dissolve in 1.000 mL of solution, which one has the largest Ksp?

Solution: They are the same. Click here to see the explanation.

One common mistake students make is to simply look at the Ksp and think that constant tells them everything they need to know about the solubility when two slightly soluble salts are compared. If you are thinking this way, then you certainly aren't thinking like a chemist. A chemist would think through the process shown in the example below.

Ranking the solubility of slightly soluble salts given the Ksp. Note: This is sped up to keep the content under the time limit for YouTube. Forgive me for sounding like Alvin and the Chipmunks.

After reviewing this material you should be able to complete the following problems:

Mastering Chemistry Solubility Assignment
Solubility Constant Expression Tutorial
Introduction to Solubility and the Solubility Product Constant Tutorial
The Solubility Product in Medicine Tutorial
*Solubility Quiz Question #1
*Solubility Quiz Question #2

Questions 1-18 from the Solubility homework set posted on Carmen.

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