Answer to Question #183540 in General Chemistry for Mugiwara

Question #183540

A solution containing 4.50 g of a non electrolyte (i=1) dissolved in 125 g of water

freezes at -0.372ºC. Calculate the molar mass of the solute.

Step 1: First compute the molality of the freezing point equation.

Step 2. Then, from the definition of molality, compute the number of moles

solute, n(solute), in the sample.

Step 3. Solve for the molar mass.

Expert's answer

"\\Delta T_{f}=i*m*K_{f}"

where "\\Delta T_{f}" is depression in freezing point.

m is molality of the solution.

"K_{f}" is molal freezing point depression constant

calculating m now,

"m = \\frac{w_{solute}}{M_{solute}*w_{solvent}(in kg)}"

"\\Delta T_{f} =0.372\\degree C"

"\\Delta K_{f}= 1.86\\degree C\/m"

From here we can calculate m, which turn outs to be 0.2 m.

from here using Molality formula, "M_{solute}=" 180 g.

Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!


No comments. Be the first!

Leave a comment

Ask Your question

New on Blog