Post At6HgMSGpHp6wusiFU by brianb@fosstodon.org
 (DIR) More posts by brianb@fosstodon.org
 (DIR) Post #At6Hg7G1KY6zoa2DZY by brianb@fosstodon.org
       2025-04-15T00:41:52Z
       
       0 likes, 1 repeats
       
       #chemistry people:We're working on pH and acid base equilibria in one of my classes. If I had them do a lab where they prepare two solutions - acetic + ammonium hydroxide - at known concentrations, measure pH, and then calculate Ka/Kb, are there other extensions that would make it more rigorous?We have not done buffers or weak titrations yet - I'm slowly working my way there.#askfedi #teaching
       
 (DIR) Post #At6HgCYzbRG6GrwwL2 by brianb@fosstodon.org
       2025-04-15T00:44:10Z
       
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       My other thought was to have them do the calculations to reach a specific pH and then dilute stock to that concentration and then measure with a pH probe. They can do all the theory work ahead to prepare a specific solution and then practice careful, quantitative lab skills to actually make the thing.That might be a better bridge to buffers, preparing solutions to be a specific pH, before going into common ions and conjugate salts to resist pH change.
       
 (DIR) Post #At6HgHXP6lxVhOFF3Y by brianb@fosstodon.org
       2025-04-15T00:46:04Z
       
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       I kind of like this idea because it will also (probably) mean a _series_ of dilutions, so they'll have to think about how to create their own procedure to get from point A to point B.
       
 (DIR) Post #At6HgMSGpHp6wusiFU by brianb@fosstodon.org
       2025-04-15T00:56:41Z
       
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       That may be too much for this lab. I think I'll stick with a more generalized approach where they make several solutions and then measure the pH. They can calculate the H+ and OH- ion concentrations and then calculate Ka/Kb and compare to published.