Chemistry
posted by Tracy on .
The boiling point of an aqueous solution is 102.16 C. What is the freezing point?
Dr. Bob, If you happen to answer this question, I was the one that a question earlier about how to know what Kf constant to use [water vs benzene?] and i didn't notice that it was given in the problem but I was wondering how you know which K constant to use in problems like these when they don't tell you what the aqueous solution is. Please help! Thank you so much ahead of time if this question is addressed!

They MUST tell you in the problem. If they use the word aqueous you know it is water. Otherwise they will say in benzene, naphthalene, etc. (Aqueous means a solution in water).
delta T = (102.16100) = Kb*m
Solve for m
Then for freezing,
delta T = Kf*m
You know Kf and m, solve for delta T and subtract from O C. 
OHHHHHHHHHHHHHHHHHHHHHHHHHH....... THANKS DR BOB!!!! always so helpful