Today I went over the concepts behind the separations in Exp #25 Group I. This content serves two purposes: #1. To get you to understand the concepts behind the lab you are performing, and #2. To set the stage and introduce some concepts such as the common ion effect, which will enable us to manipulate solubility.
After describing the separations from Group I, I calculated the molar solubility of Cd(OH)2 given the amount (in grams) that dissolved per liter. I then used this example to tie into the common ion effect, which directly ties into Le Chatlier's principle to predict the solubility of a slightly soluble salt.
The four main factors influencing solubility that we will look over in class are:
1. Common Ion Effect
2. pH
3. Complex Ion Formation
4. Amphoterism
I did a calculation of the common ion effect today and briefly introduced the strong acids and bases. The following link shows the complete list of strong acids and strong bases. Everything else is weak. You will need to know this list in order to determine how acidic/basic the salts of conjugate acids/bases are. We will start class on Wed. covering how pH influences solubility.
Song played before class:
Rihanna - Umbrella
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