# Chemistry

posted by Lauren

Confused on these, please explain or show work for the answer if you can. :)

1. What is the morality of a water solution that freezes at -0.633°C?

2. What is the freezing point of a solution that contains 1.99 g of a molecular solute of molar mass 58.5 g/mol in 58.0 g water?

3. What is the molar mass of a molecular solute, if dissolving 100. g of the solute in 1000 g water produces a solution that freezes at -2.12°C?

4. What is the molar mass of a non-electrolyte solute, if dissolving 0.876 g of the solute in 15.0 g water produces a solution that freezes at -1.47°C?

5. How many grams of a solute that has a molar mass of 164 g/mol must be added to 1.330 kg water to produce a solution that freezes at -4.13°C?

1. DrBob222

1. First, this has no answer since you don't know if the solute is ionic or not.Also, I don't know much about the morality of solution. I do know about molality. Assume it is non-ionic, then
dT = Kb*m
dT is 0.633, you know Kb, solve for m.

2.
dT = Kb*m
dT you know, Kb you know.
m = mols/Kg solvent. mols you get from grams/molar mass and kg solvent is 0.058 L.

3.
dT = Kb*m
dT 2.12. Substitute and solve for m = molality. Then m = mols/kg solvent. You know m and kg solveent , solve for mols. Then mols = grams/molar mqass. You know mols and grams, solve for molar mass.

4.
See #3.

5.
Same as 3 and 4 except you will solve for grams and not molar mass in the last step

Post your work if you get stuck.
In the future it would be better to post one problem at a time.

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