QUICK Chem question!!!

[yhelothar]

How do you find the freezing point of an aqueous solution just from knowing the density of the solution?

YES, I did google. All links seem to show that the molality is required to find the freezing point.

EDIT:
Oh yeah, I forgot to mention the solution is ChER2Y, and it has a molar mass of 15.74g.

 

[darkswordsman17]

You know, I should be able to help you with this, considering that I've taken Chem twice in college, and one of those times being just this last semester, but I don't have any idea. Let me see if I can find my book.

 

[TheoPetro]

isnt this related to freezing point depression or something>?

 

[dug777]

well, the only change to the density of the solution will be due to the solute, if you know what the solute is you should be able to work it out from there...?

 

[l Xes l]

what flavor is the liquid?

 

[TheoPetro]

o god. you know the freezing point of water and you know the density of the solution from these two you should be able to find the freezing point of the water w/ stuff in it. im done with my chem and dont care to EVER relive those memories so im not gonna grab my book. sorry.

 

[yhelothar]

Oh yeah, I forgot to mention the solution is ChER2Y, and it has a molar mass of 15.74g.

 

[TheoPetro]

...

 

[darkswordsman17]

Originally posted by: TheoPetro
o god. you know the freezing point of water and you know the density of the solution from these two you should be able to find the freezing point of the water w/ stuff in it. im done with my chem and dont care to EVER relive those memories so im not gonna grab my book. sorry.

Amen to that. I lied, I'm not looking for my book, partly because I'm doing Econ stuff and don't want to send my brain off on a tangent. That, and I really don't like chemistry anymore for some reason (which is odd, because I really enjoy science in general, and never had a problem with it before).

 

[TheoPetro]

Originally posted by: darkswordsman17

Originally posted by: TheoPetro
o god. you know the freezing point of water and you know the density of the solution from these two you should be able to find the freezing point of the water w/ stuff in it. im done with my chem and dont care to EVER relive those memories so im not gonna grab my book. sorry.

Amen to that. I lied, I'm not looking for my book, partly because I'm doing Econ stuff and don't want to send my brain off on a tangent. That, and I really don't like chemistry anymore for some reason (which is odd, because I really enjoy science in general, and never had a problem with it before).

i was all setup to major in chem then i took my first few classes. kicked ass on the labs but the lecture was so Fing boring. needless to say im onto physics and EE now

EDIT: must be a platypus thing

 

[yhelothar]

Well I guessed how to do it before, but the answer didn't look right.
Basically since density is inversely related to the freezing point(higher density means lower freezing point).
So I divided the density of H2O, or 1g/mL, with the density of the solution, or 1.023g/mL, and that gives me around 97%
Then I multiplied that number by the freezing point of water, 273 kelvins, and I get 266.6938 kelvins, or around -6°C
That temp seems a bit cold for the freezing point.

 

[TheoPetro]

any solution will drop the freezing point.....i think

 

[darkswordsman17]

Originally posted by: TheoPetro

Originally posted by: darkswordsman17

Originally posted by: TheoPetro
o god. you know the freezing point of water and you know the density of the solution from these two you should be able to find the freezing point of the water w/ stuff in it. im done with my chem and dont care to EVER relive those memories so im not gonna grab my book. sorry.

Amen to that. I lied, I'm not looking for my book, partly because I'm doing Econ stuff and don't want to send my brain off on a tangent. That, and I really don't like chemistry anymore for some reason (which is odd, because I really enjoy science in general, and never had a problem with it before).

i was all setup to major in chem then i took my first few classes. kicked ass on the labs but the lecture was so Fing boring. needless to say im onto physics and EE now

EDIT: must be a platypus thing

Haha, yeah.

I took it first semester when I was a Mechanical Engineer Major, and got stuck with a 7:30AM class for lecture, and I had some majore issues adjusting, so I never went to lecture. The labs were so easy, but I didn't study much for the tests and ended up pulling a D. Took it again last semester, thinking I'll like it more this time around, and of course they had switched to a brand new book, and I hated the class just as much this time around. At least I didn't have to redo the labs.

 

[dug777]

Originally posted by: virtualgames0
Well I guessed how to do it before, but the answer didn't look right.
Basically since density is inversely related to the freezing point(higher density means lower freezing point).
So I divided the density of H2O, or 1g/mL, with the density of the solution, or 1.023g/mL, and that gives me around 97%
Then I multiplied that number by the freezing point of water, 273 kelvins, and I get 266.6938 kelvins, or around -6°C
That temp seems a bit cold for the freezing point.

why?

i have no idea myself but...

this is kinda cool

http://www.es.flinders.edu.au/~mattom/Utilities/freeze.html

 

[FleshLight]

Freezing Point = Freezing Point Constant of Water * ( (Mass of Substance)/(Molar Mass of Substance) ) / (Volume of Substance)

 

[TheoPetro]

holy ass are we the same person? this is exactly what happened to me. i got screwed on chem 2 spring of 05 and had to retake it fall of 05 but not the labs. i pulled a C round 2 tho.

 

[yhelothar]

Originally posted by: FleshLight
Freezing Point = Freezing Point Constant of Water * ( (Mass of Substance)/(Molar Mass of Substance) ) / (Volume of Substance)

Yeah I found that equation all over google.. So how do I do that when I'm just given the density of a solution?

 

[darkswordsman17]

Originally posted by: TheoPetro
holy ass are we the same person? this is exactly what happened to me. i got screwed on chem 2 spring of 05 and had to retake it fall of 05 but not the labs. i pulled a C round 2 tho.

That is pretty weird. I've heard that every person has a counterpart somewhere in the world, but they pretty much never meet or know of the other's existence, maybe thats the case?

The funniest part is that the first time I took it, two girls from my high school graduating class were in the same class as me, and they went to pretty much every class and took tons of notes, and studied a ton for each test, and they did worse than I did.

I just noticed that we hijacked this thread. At least he got some bumps I guess.

 

[TheoPetro]

you know the desnity of water (look it up) then find the density of the solute then thatll give you grams of solute (napolian) GOSH! (end napolian)

 

[Fenixgoon]

freezing point depression -T = Kf m where Kf is your freezing point constant, and m is your molality (kilograms of solute / kilograms solution)

you can do density solute / density water, perhaps