How do you calculate molal freezing point depression constant?
How do you calculate molal freezing point depression constant?
The freezing point depression ∆T = KF·m where KF is the molal freezing point depression constant and m is the molality of the solute. Rearrangement gives: mol solute = (m) x (kg solvent) where kg of solvent is the mass of the solvent (lauric acid) in the mixture. This gives the moles of the solute.
What are the boiling point and freezing point of a 2.47 m solution of naphthalene in benzene?
Question: What are the boiling point and freezing point of a 2.47 M solution of naphthalene in benzene? The boiling point and freezing point of naphthalene are 80.1 C and 5.5 C, respectively, and Kb=2.53∘C/M,Kt=5.12∘C/M K b = 2.53 ∘ C / M , K t = 5.12 ∘ C / M .
What is the kb of naphthalene?
Molal Freezing and Boiling Point Data
| Solvent | Kf (°C kg/mol) | Kb (°C kg/mol) |
|---|---|---|
| 2-Methyl-2-propanol | 8.37 | |
| Naphthalene | 6.94 | 5.80 |
| Nitrobenzene | 6.852 | 5.24 |
| Phenol | 7.40 | 3.60 |
What is depression in freezing point How is molecular weight of a dissolved substance determined with this method?
The freezing point depression is explained as the lowering of the freezing point of the solvent with the addition of the solute. The freezing point depression is the colligative property which is proportional to the molality of the solute added.
What is molal depression constant KF?
The depression in freezing point in a solution in which 1 gm mole of solute dissolved in 1000 gm of solvent is known as molal depression constant represented by Kf. Numerical: Given value, Freezing point of solution =−0. 385oC.
What is the freezing point of naphthalene in benzene?
Naphthalene is the main ingredient in some mothballs. The freezing point of a solution made by dissolving 7.01 g of naphthalene in 200 g of benzene is 4.20∘C .
What are the boiling point and freezing point of a 3.12 M solution of naphthalene in benzene?
Boiling pt: 88*C; Freezing pt: -10.47*C.
How do you find freezing point depression and freezing point?
Strategy:
- Step 1: Calculate the freezing point depression of benzene. Tf = (Freezing point of pure solvent) – (Freezing point of solution)
- Step 2 : Calculate the molal concentration of the solution. molality = moles of solute / kg of solvent.
- Step 3: Calculate Kf of the solution. Tf = (Kf) (m)
What happens to the freezing point of benzene when naphthalene is added?
Solution : On adding naphthalene (volatile component) to benzene, its freezing point (which is a colligative property) decreases.
What is molal freezing point depression constant derive the formula and find molecular mass of solute?
ΔTf=kfm, where Kr is a constant of proportionality. If m = 1 molal, ΔTr= Kf. Hence Kr is called the cryoscopic constant or molal depression constant. If W1 grams of a solvent contain W2 gram of a solute of the molar mass M2 , them the molality m of the solution is given by .
What happens to freezing point of benzene when naphthalene is added?
Solution : Freezing point temperatue of benzene decreases.
What happened to freezing point when naphthalene added?
What happens to the freezing point of benzene when naphthalene is added? Solution : On adding naphthalene (volatile component) to benzene, its freezing point (which is a colligative property) decreases.
What happens when naphthalene is added to water?
Napthalene balls do not dissolve in water. So no chance for changing and the property of napthalene should not change.