Today we looked at percent composition and a couple ways to use percent composition to determine empirical and molecular formulas. In one of the problems I worked through on the board, I made a slight mistake, so I'll try to clear that up here. We worked through a problem where we came up with an empirical formula of CH_2_. The molar mass of this substance was stated to be 84 g/mol. So the question here is, what is the molecular formula of this substance? The mass of the empirical formula is 14 g/mol (OK, 14.027 g/mol, but that's close enough to 14 g/mol that we can round...). Since the molecular formula must be a multiple of the empirical formula, then we know that 14*(some whole number)=84. Solving, 84/14 = 6, so the molecular formula must be 6x the empirical formula, or C_6_H_12_.
Check out the Natural Sciences Research Night this evening at 5:30 in SL104. A number of faculty in the natural sciences will present brief descriptions of their research, so if you're interested in doing research this is a great opportunity to learn about what's going on.
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Is there another SI session anytime soon?
ReplyDeleteHey everyone!
ReplyDeleteSI is tomorrow at 1:30-2:20! Let's meet outside the lecture room where you usually meet and we will go up to the third floor of the science building again!
Hope to see you all there :)
Sara
p.s. I'm still waiting to hear about the room assignments. As of now the only room I have is for the Wednesday session at 5:30-6:20 in Bridges (BR 269).
ReplyDeleteHey!
ReplyDeleteTuesday SI is in LO 84 at 1:30
Wednesday BR 269 at 5:30
Thursday 12:30 in BR 268
Those are the SI times and places...
See ya there!
Sara