1. Define and describe the Lewis theory of acids and bases.
2. Classify substances as Lewis acids or bases.
3. Define and describe a buffer and, using equations, show how a buffer system works.
4. Based on the hydrolysis of salts, predict the pH of salt solutions as acidic, basic or neutral.
In this video, there's a detailed review of Bronsted-Lowry theory, but that helps to clarify the Lewis theory of acids and bases. He does talk about Bronsted-Lowry rather quickly, so you might want to check out my previous post about this theory.
To get a little history of Gilbert N. Lewis, here's the Wikipedia entry:
Here's a worksheet with answers that touches on both Bronsted-Lowry theory and Lewis acid-base theory:
A buffer is a weak acid and its conjugate base in an equilibrium system. Here is a brief explanation:
Here are 10 multiple choice questions on acid-base buffers:
From http://www.science.uwaterloo.ca/~cchieh/cact/c123/salts.html , this explanation of acid-base hydrolysis is presented:
"When weak acids and bases react, the relative strength of the conjugated acid-base pair in the salt determines the pH of its solutions. The salt, or its solution, so formed can be acidic, neutral or basic. A salt formed between a strong acid and a weak base is an acid salt, for example NH4Cl. A salt formed between a weak acid and a strong base is a basic salt, for example NaCH3COO. These salts are acidic or basic due to their acidic or basic ions..."
Here is a demonstration of the hydrolysis of various salts:
Here's one lab procedure to test the pH of salts:
You might have to alter the salts used based on availability.
Here is another lab that might have to be edited.
Rather than use a full set of chemicals for a pair of students, you may want to set up stations that pairs can travel to and test the salt's pH.
Here's an acid-base Powerpoint presentation that you might find useful. This link sends you to a very complete (long) PowerPoint presentation. Warning: it has sound effects!
Here's a worksheet with background and ending in questions:
I have a few links listed under Teaching Resources that could be very useful -- if you haven't checked it out, the link is at the top of this page!
Check out my lab book "Chemistry on a Budget" at amazon.com:
Each lab is presented with two possible report formats -- both labs use the same procedure page but each has a different conclusion page -- one with 10 questions to be answered as a conclusion, the other with a full laboratory report required. This gives the teacher the option of what type of report is desired!
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Have a good end of the week!