 |
02-05-2009, 06:09 PM
|
#1
|
|
Registered User
Join Date: Jun 2008
Stats: 5'3", 121 lbs
Posts: 450
BodyBlog Entries: 0
BodyPoints: 0
|
chem help, freezing point depression
This is a practice problem in our book that I can't figure out and I will likely be quizzed with a similar problem tomorrow, so help would be greatly appreciated
A solution is prepared by mixing 2.17 g of an unknown non-electrolyte with 225.0 g of chloroform. The freezing point of the resulting solution is -64.2 degrees C. The freezing point of pure chloroform is -63.5 degrees C and its kf is 4.68 degrees C m^-1. What is the molecular mass of the unknown
Here's how I set it up
deltaT: -64.2 - -63.5 = -.7
(kf x g solute) / (deltaT x kg solvent)
(-4.68 x 2.17) / (-.7 x .225)
I'm getting 64.48 g/mol, but the answer is supposed to be 69.3 g/mol...did I set it up all wrong?
|
|
|
|
02-05-2009, 06:13 PM
|
#2
|
|
500 Internal Server Error
Join Date: Sep 2008
Age: 17
Stats: 5'11", 164 lbs
Posts: 2,989
BodyBlog Entries: 0
BodyPoints: 0
|
IDK, that's what I'm getting...
|
|
|
|
02-05-2009, 06:14 PM
|
#3
|
|
Registered User
Join Date: Jun 2008
Stats: 5'3", 121 lbs
Posts: 450
BodyBlog Entries: 0
BodyPoints: 0
|
Quote:
Originally Posted by SomeRandomName
IDK, that's what I'm getting... although if it doesn't dissociate there shouldn't be an answer anyway.
|
I'm not even sure if I set the problem up correctly, that was kind of pieced together after loads of google searching. This book was written by my school's staff, so there are possible errors. I hope that's the case.
|
|
|
|
|
02-05-2009, 06:16 PM
|
#4
|
|
Registered User
Join Date: Jun 2008
Location: Canada
Age: 19
Stats: 6'0", 164 lbs
Posts: 391
BodyBlog Entries: 0
BodyPoints: 0
|
bout 350 g/mol
__________________
Weak Ass Legs Crew
****
"Everything you do, every decision you make, either takes you a step closer or a step further away from your goal. You either grow or you regress; nothing stands still."
|
|
|
|
|
02-05-2009, 06:17 PM
|
#5
|
|
lolololololololololololol
Join Date: May 2007
Location: New Jersey, United States
Age: 18
Stats: 5'7", 150 lbs
Posts: 2,061
BodyBlog Entries: 0
BodyPoints: 1263
|
if you did not get 69.3, youre wrong.
|
|
|
|
|
02-05-2009, 06:19 PM
|
#6
|
|
let's hug it out, bitch
Join Date: Jun 2008
Stats: 6'1", 175 lbs
Posts: 1,769
BodyBlog Entries: 0
BodyPoints: 0
|
I'm lolling at the fact that I did a bunch of these problems earlier for my chem class. However, I don't really have time to do other people's chem, I shouldn't even be miscing right now. It could be that your rounding throughout the problem was different than what the professor/TA had done.
__________________
MMMC
|
|
|
|
|
02-05-2009, 06:19 PM
|
#7
|
|
Registered User
Join Date: Jun 2008
Stats: 5'3", 121 lbs
Posts: 450
BodyBlog Entries: 0
BodyPoints: 0
|
Quote:
Originally Posted by TheSpectre
I'm lolling at the fact that I did a bunch of these problems earlier for my chem class. However, I don't really have time to do other people's chem, I shouldn't even be miscing right now. It could be that your rounding throughout the problem was different than what the professor/TA had done.
|
But, I'm not other people, I'm powerbarsssssss!
|
|
|
|
|
02-05-2009, 06:20 PM
|
#8
|
|
let's hug it out, bitch
Join Date: Jun 2008
Stats: 6'1", 175 lbs
Posts: 1,769
BodyBlog Entries: 0
BodyPoints: 0
|
Quote:
Originally Posted by powerbarsssssss
But, I'm not other people, I'm powerbarsssssss!
|
Your attention whore antics shant work on me m'lady.
__________________
MMMC
|
|
|
|
|
02-05-2009, 06:21 PM
|
#9
|
|
Registered User
Join Date: Jun 2008
Stats: 5'3", 121 lbs
Posts: 450
BodyBlog Entries: 0
BodyPoints: 0
|
Quote:
Originally Posted by TheSpectre
Your attention whore antics shant work on me m'lady.
|
Only I don't post pics in thongs, my avatar isn't of my boobs, I'm not begging the misc to buy me a car, and I'm not posting stories of made up gang bangs for reps.
Shoot, I deserve help for not being an attention whore 
|
|
|
|
|
02-05-2009, 06:27 PM
|
#10
|
|
lolololololololololololol
Join Date: May 2007
Location: New Jersey, United States
Age: 18
Stats: 5'7", 150 lbs
Posts: 2,061
BodyBlog Entries: 0
BodyPoints: 1263
|
you made a thread about chemistry, nuff said.
|
|
|
|
|
02-05-2009, 06:38 PM
|
#11
|
|
Registered User
Join Date: Apr 2007
Age: 23
Stats: 6'3", 215 lbs
Posts: 3,662
BodyBlog Entries: 0
BodyPoints: 14188
|
|
|
|
|
|
02-05-2009, 06:41 PM
|
#12
|
|
Registered User
Join Date: Jun 2008
Stats: 5'3", 121 lbs
Posts: 450
BodyBlog Entries: 0
BodyPoints: 0
|
Quote:
Originally Posted by AppleCat
|
You're awesome. Thanks and reps!
|
|
|
|
|
02-05-2009, 06:41 PM
|
#13
|
|
500 Internal Server Error
Join Date: Dec 2008
Age: 19
Posts: 801
|
Here's a visual aid that should help you out.
|
|
|
|
|
02-05-2009, 06:45 PM
|
#14
|
|
Registered User
Join Date: Jun 2008
Stats: 5'3", 121 lbs
Posts: 450
BodyBlog Entries: 0
BodyPoints: 0
|
I was originally going to add "in before chloroform joke" at the bottom of my post. I regret that I didn't!
|
|
|
|
| Thread Tools |
|
|
| Display Modes |
Rate This Thread |
 Linear Mode
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
Member Login
Sign in for more FREE features and tools!
|
|
