chem
posted by paula .
what is the molality of a solution of 50.0 grams of propanol in 152 mL water if the density of wate is 1.0 g/mL and the density of the solution is 0.78 g/mL

m = moles/kg solvent
moles propanol = g/molar mass propanol = ??.
m = ??moles/0.152 
I am not sure what to do with the density of the solution of 0.78 g/mL.
The answer I came up with is 5.47 mol/kg. I found the density of the water in grams then I converted it to kg (152 x .001 = .152. I divided 50 g by the molar mass of 60.09502 g/mol = .8320 moles. Next, I divided that by .152. However, I didn't use the .78 g/mL beacause I am not sure what to do with it. Please explain. 
5.47 molal is correct. You don't need the density of the solution.
Respond to this Question
Similar Questions

chemistry
A solution of HCI has a density of 1.18 g/ml and is 36% (m/m). what is the molarity and molality of this solution? 
Chemistry
A teacher prepares a saturated NaCli solution at 55 Degree C. What is the % by mass 9m/m0 of this solution? 
Chem
I'm having a lot of trouble with a simple problem. I have a 3.0% by man solution of H2O2 in H2O. The density of thr solution is 1.0 g/mL. I need to find the molarity. How do I do this? 
CHM 152
At 20oC, a 2.32 M aqueous solution of Ammonium Chloride has a density of 1.0344g/ml. WHat is the molality of Ammonium Chloride in the solution? 
CHEM
a solution containing 30 g of nh3 in 70 g of water has a density of 0.882 g/ml. what is the molarity and molality 
chem
I am still having a little problem with my original question. However, this is what I have done so far. I am not sure what to do with the density of the solution of 0.78 g/mL. The answer I came up with is 5.47 mol/kg. I found the density … 
Chem
An aqueous KNO3 solution is made using 82.7 grams of KNO3, diluted to a total solution volume of 1.50 L. The density of this solution is 1.05 g/mL. What is the molality of this solution? 
chemistry
this is a really long question. i don't understand how to answer it. help please. A 10.0% aquueous solution of sulfuric acid has a density of 1.0661 g/mL at 20 degrees celsius. A. how many grams of H2SO4 are found in 50.0 g of this … 
CHEMISTRY
An ethanolwater solution is prepared by dissolving 10.00 ml ethanol C2H5OH (density=0.789g/ml) in sufficient water to produce 100.00 ml of solution with a density of 0.982g/ml. What is the concentration of ethanol in this solution? 
chemistry
I have to prepare a 0.2% water solution of npropanol and a water solution of methanol and isopropanol at 0.2% that can be in the same container. It didn't specify but I'm pretty sure the solutions are v/v%. For the npropanol a 0.2% …