Posted by: unlikelygrad | April 13, 2010

grading again

My quant lab students were supposed to determine the Ka of both a known and unknown acid. Reading their lab reports is interesting:

One student has plotted his titration data with pH on the x-axis and volume NaOH on the y-axis. This makes for an interesting-looking titration curve.

One student called her known solution “acidic acid”–as opposed to “basic acid,” I assume? (For the record, it was acetic acid. And since this name was written in the instructions, she has no excuse.)

Finally, there’s the student who clearly misunderstood the whole basis for the experiment:

The equilibrium constant of a base (or an acid) is important to know because it tells us the molarity of a solution at a specific temperature. If the molarity of an unknown solution is known then it can be used to find the molecular weight of the unknown substance which will in turn aid in finding out what chemicals or elements are in the solution.

All this from a simple acid-base titration with pH meter! I should investigate her methods…maybe I could revolutionize chemistry and win the Nobel Prize! (Don’t I wish?)

Advertisements

Responses

  1. I think “acetic” is actually from the French for “acidic”…


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Categories

%d bloggers like this: