Today there were many students away because of the playland field trip for Earth Science and Physics so we did not move too far ahead. We did calculations involving kb -- see the board notes and example below. Essentially, these calculations are the same as what we did on Monday with the ICE charts but because the predominant hydrolysis reaction is basic -- all the calculations must be about a base. Instead of Ka - we use Kb (remember this must be caluclated), instead of pH we use pOH, instead of [H30+] we use [OH-].
Students were given class time to complete the following worksheet:
The answers to the questions that were assigned are in the photo below. Watch out for g, h and K -- these ones have amphiprotic species -- so before you can do an ice chart you must compare the ka and kb of both reactions and decide which reaction is the dominant one -- if it is ka that is greater -- then the ice chart and the calculations will all be for an acid. If the kb is greater -- then everything will be calculated for a base!!
There will be a 4 question quiz on ka and kb on Monday!!!
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