Assume that the density of water is 1.00 g/ml . Calculate the quantity of KBr that would need to be added to lower the freezing point of 535 ml of water by 1.40 degree celsius:(adsbygoogle = window.adsbygoogle || []).push({});

What I'm trying to do is the following:

Step 1:

Tf = Kf . m

I took Tf = 1.4

Kf = 1.86

and found the molality as 0.75

Step 2:

then I used the molality equation which is

molality = moles solute/kg solvent

molality = 0.75

kg solvent = 0.535 kg

and got the no. of moles as 119 g/mol

Step 3

no. of moles = mass /molar mass and

got 47.6 g for mass

but the answer is still wrong ... I don't know where I'm making mistake. It's an online assignment so I don't know what the answer should be. But please guys help me and check if I'm doing everything right.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Density and freezing point

**Physics Forums | Science Articles, Homework Help, Discussion**