- #1
soggybread
- 20
- 0
Having a massive brain fart... SIMPLE "molarity -> molality" conversion...
This isn't even a homework question per se, I'm just trying to understand how the question converted the molarity to the molality value, via the density given. I just got a different value of molality when trying to solve for it manually... and am pretty sure I did something stupid.
If the osmotic pressure of a 6.02×10-2 M aqueous solution of Ca(NO3)2 was found to be 4.05 atm at 20°C. Note that the corresponding molality would be 6.10×10-2 m, given that the density of the solution is 0.997 g/cm3...
None.
Okay... so the question tells me it has a molality of 6.10×10-2 m,
So if I want to solve for that myself, I would start off with the given molarity, right? So it would be 6.02×10-2 M then multiply it by the density of solution, 0.997g/cm3, or in other words, 0.997kg/1L ... and then we're done, right?
So:
6.02×10-2 mol/L multiply 1L/0.997kg = 6.04x10-2
... but the question tells me it's 6.10×10-2 m ... and I have no idea why I'm not getting that value.
I don't know what's going wrong here... I'm sure I am missing something dead simple...
This isn't even a homework question per se, I'm just trying to understand how the question converted the molarity to the molality value, via the density given. I just got a different value of molality when trying to solve for it manually... and am pretty sure I did something stupid.
Homework Statement
If the osmotic pressure of a 6.02×10-2 M aqueous solution of Ca(NO3)2 was found to be 4.05 atm at 20°C. Note that the corresponding molality would be 6.10×10-2 m, given that the density of the solution is 0.997 g/cm3...
Homework Equations
None.
The Attempt at a Solution
Okay... so the question tells me it has a molality of 6.10×10-2 m,
So if I want to solve for that myself, I would start off with the given molarity, right? So it would be 6.02×10-2 M then multiply it by the density of solution, 0.997g/cm3, or in other words, 0.997kg/1L ... and then we're done, right?
So:
6.02×10-2 mol/L multiply 1L/0.997kg = 6.04x10-2
... but the question tells me it's 6.10×10-2 m ... and I have no idea why I'm not getting that value.
I don't know what's going wrong here... I'm sure I am missing something dead simple...