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. 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.
1. To determine the morality of a water solution, you need to know the freezing point depression constant (Kf) of the solvent, in this case, water. The morality can be calculated using the formula:
Morality = (Freezing Point Depression) / (Freezing Point Depression Constant)
In this case, the freezing point of the water solution is given as -0.633°C. The freezing point of pure water is 0°C.
Freezing Point Depression = (0 - (-0.633)) = 0.633°C
The freezing point depression constant for water is 1.86°C/m.
Morality = (0.633°C) / (1.86°C/m) ≈ 0.34 m
2. To find the freezing point of a solution, you can use the formula:
Freezing Point Depression = (Number of moles of solute) * (Freezing Point Depression Constant)
First, you need to determine the number of moles of the solute.
Number of moles of solute = (Mass of solute) / (Molar mass of solute)
In this case, the mass of the solute is given as 1.99 g, and the molar mass of the solute is given as 58.5 g/mol.
Number of moles of solute = (1.99 g) / (58.5 g/mol) ≈ 0.034 mol
Now, you can calculate the freezing point depression:
Freezing Point Depression = (0.034 mol) * (1.86°C/m) ≈ 0.0632°C
The freezing point of the solution is the freezing point of the solvent minus the freezing point depression.
Freezing Point = 0°C - 0.0632°C ≈ -0.0632°C
3. To find the molar mass of a solute, you can use the formula:
Molar mass of solute = (Mass of solute) / (Number of moles of solute)
In this case, the mass of the solute is given as 100. g and the mass of the water is given as 1000 g.
Number of moles of solute = (100. g) / (Molar mass of solute)
Number of moles of water = (1000 g) / (Molar mass of water)
Using the freezing point depression formula as mentioned in the previous explanation:
Freezing Point Depression = (Number of moles of solute) * (Freezing Point Depression Constant) + (Number of moles of water) * (Freezing Point Depression Constant)
In this case, the freezing point depression is given as -2.12°C.
Solving the equation for the molar mass of the solute will give you the answer.
4. The same procedure explained above can be applied to find the molar mass of a non-electrolyte solute. You need to use the given information to calculate the number of moles of the solute and then find the molar mass using the molar mass formula.
5. To determine the number of grams of a solute required to produce a solution that freezes at a specific temperature, you can use the formula:
Freezing Point Depression = (Number of moles of solute) * (Freezing Point Depression Constant)
First, calculate the freezing point depression using the given information.
Then, using the same formula as explained in question 2, solve for the number of moles of the solute.
Finally, use the molar mass formula to calculate the mass of the solute.
I hope this helps you understand and solve the given problems! Let me know if you have any more questions.