collig prop demo

[robert zellmer]

Unfortunately I couldn't get the VP-lowering demo to work on Monday or Wed.
last week. Some of you may not have been in lecture on Tuesday last week 
when
it did work.  There was a crack in one of the stoppers which may have 
meant the
system wasn't sealed properly.  These were fixed and our demo staff did 
it and it
turned out really well. Here's the video.

As the solute dissolves in the flask on the left the VP decreases when 
compared
to the pure solvent on the right.  Since the VP in the flask is lower 
the higher
pressure due to the pure solvent in the flask on the right pushes the 
fluid in the
U-tube down on that side and up on the other side.

I've put it on my class web page at the "Notes" link,

http://chemistry.osu.edu/~rzellmer/chem1250/notes/vp_lowering.mp4
<http://chemistry.osu.edu/%7Erzellmer/chem1250/notes/vp_lowering.mp4>
Dr. Zellmer