Confused with Khan Academy MCAT Chemistry?

[bme94]

Hi guys,

I'm a little confused here. I went to review titrations under the "Chemical and Physical Processes" section for the MCAT, and came across a sub-section that's called "acid-base titration curves." I scrolled down to where they showed the graphs for the titration of a SA w/ a SB and a WA w/ a SB....but the graphs look nearly identical. This isn't right, is it? My Berkeley review book has a completely different graph for the WA w/SB...not to mention, they didn't even include anything about the half-equivalence point. Am I missing something important? Thanks for the help.

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[NextStepTutor_2]

Hi guys,

I'm a little confused here. I went to review titrations under the "Chemical and Physical Processes" section for the MCAT, and came across a sub-section that's called "acid-base titration curves." I scrolled down to where they showed the graphs for the titration of a SA w/ a SB and a WA w/ a SB....but the graphs look nearly identical. This isn't right, is it? My Berkeley review book has a completely different graph for the WA w/SB...not to mention, they didn't even include anything about the half-equivalence point. Am I missing something important? Thanks for the help.

Can you provide a screenshot or link? The KA MCAT materials, particular their passages, have quite a few errors and mistakes. That is why they are ideally used as a supplement, not a primary MCAT resource.

Below are some examples of strong vs. strong and strong vs. weak. To test yourself see if you can identify which species is the titrant and which is the analyte (unknown).

STRONG ACID V STRONG BASE

STRONG ACID V WEAK BASE

WEAK ACID V STRONG BASE

Weak vs weak is much too complex to predict accurately and varies, so the AAMC doesn't bother with it.

hope this helps, good luck!