Question

A certain substance X has a normal freezing point of -6.4 C and
a molal freezing point depression constant K_{f}= 3.96
degrees C^{.}kg^{.}mol^{-1}. A solution is
prepared by dissolving some urea ((NH_{2})_{2}CO)
in 950. g of X. This solution freezes at -13.6 C. calculate the
mass of urea that was dissolved. Round your answer to 2 significant
digits.

Answer #1

Problem Page A certain liquid X has a normal freezing point of
−8.9°C and a freezing point depression constant
Kf=5.59·°C·kg*mol−1.
Calculate the freezing point of a solution made of 66.5g of
benzamide (C7H7NO) dissolved in 900.g of X.
Be sure your answer is rounded to the correct number of
significant digits.

Benzene has a normal freezing point of 5.50°C and a molal
freezing point depression constant of 5.12°C/m. A solution prepared
by dissolving 0.335g of compound X in 5.00g of benzene has a
freezing point of 1.34°C. Assuming that compound X is a
nonelectrolyte, what is the molar mass of compound X?

The freezing point depression constant tells how the temperature
changes for a 1 molal concentration of solute. If camphor is
dissolved in cyclohexane so that the concentration is 1.5 molal,
what is the freezing point of the solution? (See Table in lab
procedure for Kf values.)
What are the five major steps in this experiment? a.
b. c. d. e.
An important hazard of cyclohexane is
__________________________________. How will you know if the solute
is completely dissolved?
Howdoyoucleanupthetesttubeattheendoftheexperiment?
4. 5....

The normal freezing point of a certain organic solvent is 5.50
degrees C. When 0.3003 g of naphthalene (C10H8) is dissolved in
9.9876 g of this solvent, the solution has a freezing point of 4.32
Degrees C. What is the freezing point depression constant (kf) in
Degree C/m, for this solvent?

5. Determine the molal freezing point depression constant (Kf)
(in °C⋅kg/mol) of water by using the data of three NaCl solutions .
Use Equation 3 in the “Background and Procedure” file, the molality
values of all solutes from Question s 1 – 3 and the freezing point
depression ( ∆T) from Question 4. In your calculation, rewrite the
symbol“m ” (the molality) as “mol/kg” so that the molal freezing
point depression constant will have the correct unit. Make
sure to...

To use freezing-point depression or boiling-point elevation to
determine the molal concentration of a solution.
The freezing point, Tf, of a solution is lower than the
freezing point of the pure solvent. The difference in freezing
point is called the freezing-point depression, ΔTf:
ΔTf=Tf(solvent)−Tf(solution)
The boiling point, Tb, of a solution is higher than the
boiling point of the pure solvent. The difference in boiling point
is called the boiling-point elevation, ΔTb:
ΔTb=Tb(solution)−Tb(solvent)
The molal concentration of the solution, m,...

Camphor melts at 179.8oC and has a freezing point depression
constant, Kf = 40oC/molal. When 0.186 g of an unknown organic solid
is dissolved in 22.01 g of liquid camphor, the freezing point of
the mixture is found to be 176.7oC. What is the molar mass of the
solute?

Calculate the freezing point of a solution containing 30 grams of
KCL and 3300.0 grams of water. The molal-freezing-point-depression
constant (Kf) for water is 1.86 degrees Celsius/M

Assume that 0.10 moles of a certain substance is dissolved in
250. g of water. The freezing point of the resultant solution is
-2.2 °C. I: Which of the following choices is the dissolved
substance? Kf = 1.86°C/m for water.
a: C6H12O6
b: CO(NH2)2
c: NaCl
d: CaCl2
II: Calculate the % dissociation of the substance
I know the answer for (I) is D, and the answer for (II) is 98%
but I am not sure how it is achieved.

) Pure benzene, C6H6, has a density of 0.8765 g/ml, a freezing
point of 5.45oC and a boiling point of 80.2oC. Its freezing point
depression constant, Kf, is 5.07oC/m. A solution was made by taking
24.20 grams of an unknown non-electrolyte and dissolving it in
125.0 grams of benzene. The measured freezing point of the solution
was -1.65oC. Calculate the molecular weight of the unknown
substance.
258 g/mole
145 g/mole
138 g/mole
272 g/mole
595 g/mol

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 7 minutes ago

asked 17 minutes ago

asked 29 minutes ago

asked 43 minutes ago

asked 44 minutes ago

asked 45 minutes ago

asked 45 minutes ago

asked 53 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago