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Classroom vs. Lab

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This morning I was sitting in on the intro organic chemistry class that I am TAing.  Suddenly I was struck by the disparity between "paper" or "classroom" chemistry and the chemistry that we actually carry out in the lab.  For example, a simple Grignard reaction with an aldehyde is easy to draw out on paper.  However, there is quite a lot of technique involved in actually performing a Grignard reaction.  It seems that all of these subtleties are glossed over in the classroom.

So, my question is do you think students learn chemistry better in the lab or in the classroom?  I realize that both are necessary, but which is more effective?

Comments from anyone at any level are welcome!

The Lab.  Humans are visually perceptive creatures and we tend to remember things better if we see them rather than just read about them.  (Hence why so many people find quantum mechanics such a pain in the ass.  You really can't 'see' what's being talked about).  Another example is when you're driving someplace.  If you are given directions with specific landmarks that you know about used to guide you, you have an easier time getting there than if someone just says 'make a right here, a left there, and another right here'.  

In a lab, you actually get to see the chemistry happening.  You can remember how you did this, then this, and that compound was formed.  In conjunction with the lecture, there's a greater chance that it will be retained.  That's why demos are CRUCIAL to the success of any general chemistry course.

Okay, so what do you think about universities where they have a discrete lecture class and a discrete lab class.  The one lab classes covers most of the fields of chemistry (organic, inorganic, physical/analytical) but is not directly tied to the lecture portion of the class and need not be taken concurrently with any lecture classes.  

(By the way, I believe that this kind of class is what is required for an ACS accredited degree)

So how do make a grinard. Do you just toss some magnesium chips with an alkylhalide in an air-free sensitive environment?


--- Quote from: Mitch on February 23, 2005, 11:51:48 PM ---So how do make a grinard. Do you just toss some magnesium chips with an alkylhalide in an air-free sensitive environment?

--- End quote ---

It's a little more difficult than that.  Magnesium oxidizes in air so rapidly that you have to either crush the turnings once they are in the flask and under degassed solvent or activate the surface by some chemical means (e.g. iodine or dibromoethane).  Even then you often have to heat the solution to get the oxidative addition to go.  Beyond that your glassware has to be meticulously dried and air excluded.

To a grad student or someone who does bench chemistry regularly all of this stuff is pretty routine, but for a student just starting out these subtleties are far from obvious.


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