Just now reading this description of the lab solubility and thermo reminded me of a lab I had second year students perform about 35 to 40 years ago. The lab involved the solubility of lead (II) chloride at varying temperatures. At the temperature is lowered from 95 to about 75 in small increments a sample is removed. Some chromate ion is added as sodium chromate. The solution, upon cooling, is then titrated with AgNO3 until all of the chloride becomes AgCl. A drop of excess AgNO3 will form a red ppt of AgCrO4. One then graphs the data in a similar manner to what is described in the article above. Results are quite good for determining delta H and delta S.

Thanks for sharing, Heather. Do you use a graduated cylinder for the potassium nitrate throughout the experiment? It does seem like that would make the volume measurements easiest. Have you tried it with analog thermometers?

Not sure if you've noticed, but we've added a new filter to our resource library - "AP/IB Chemistry". Log on and go to the high school resources page and select a topic. Scroll down and select "Labs" and "AP/IB Chemistry" and "Submit" on the right side of the page. A list of labs that would be appropriate for and AP Chemistry class will be shown on the page.

Hi! Here's one of my favorite AP labs. I can't remember from whom I stole it. Students collect solubility data, calculate Keq, then delta G, delta H and delta S. I use it to review thermochemistry and equilibrium at the end of the term. It's easy to set up and the calculations are interesting in my opinion. Cheers! Heather