A 0.25 g sample of an unknown solid is dissolved in 8.85 g of cyclohexane. The change in the freezing point of the cyclohexane is 2.8 C. The Kf for cyclohexane is 20.0 (C*Kg)/mol. What is the molar mass of the solute?

You have an aqueous solution of NaCl that has a freezing point of -5.25°C. What mass (in grams) of NaCl must be added to 1000 g of this solution to lower the freezing point to -12.00°C? (Assume a van't Hoff factor of 1.9 for NaCl). (Kf for water is 1.86°C･kg/mol).

A student dissolves 6.7 g of biphenyl (C12H10) in 425. mL of a solvent with a density of 1.05 g/mL. The student notices that the volume of the solvent does not change when the biphenyl dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to 2 significant digits. molarity Ox10 olo Ar molality 미

2. When 3 g of an unknown solute is dissolved in 50 g of benzene, the resulting solution has a freezing point of 0.28 °C. The freezing point of pure benzene is (T) 5.40 °C and K of benzene is 5.12 °C/m. What is the molar mass of this unknown solute? A) 40 g/mol B) 50 g/mol C) 60 g/mol D) 70 g/mol E) 80 g/mol

Calculate the freezing point of a solution that contains 168.4 g of sucrose (table sugar) in 300. g of water. One mole of sucrose is 342 g. Kf for H2O = 1.86°C/m -0.185 oC -3.05 oC -0.558 oC -0.744 oC -1.24 oC

Ethylene glycol (C₂H₆O₂) is used as an additive to the water in your automobile to lower its freezing point. A solution of ethylene glycol in water has a freezing point of -8.10 °C. What is the mole fraction of ethylene glycol in this solution? (Kf for water is 1.86 °C･kg/mol).

1.613 g sample of an unknown nonionizing molecular compound is added to 250.0 g of benzene(C6H6, MW = 78.11 g/mol). The normal freezing point of the solution is 0.17 C lower than the normalfreezing point of pure benzene. Based on this information, find the molecular weight of the unknowncompound. benzene =  Kf = 5.12 kg x Degrees C/mol.

A solution of 0.890 g of an organic compound in 100.0 g of benzene has a freezing point of 5.107°C. What are the molality of the solution and the molar mass of the solute? The normal freezing point of benzene is 5.500°C and the Kf for benzene is 5.12°C/m. molality molar mass = g/mol

1. Suppose that you add 27.5 g of an unknown molecular compound to 0.250 kg of benzene, which has a Kf of 5.12 oC/m. With the added solute, you find that there is a freezing point depression of 3.58 oC compared to pure benzene. What is the molar mass (in g/mol) of the unknown compound? 2. What is the freezing point (in degrees Celcius) of 3.70 kg of water if it contains 187.4 g of CaBr2? The freezing point depression constant for water is 1.86 oC/m and the molar mass of CaBr2 is 199.89 g/mol. 3. What mass, in grams, of NaCl needs to be added to 1.6 kg of water in order to create a solution with a freezing point of -5.6 °C? The freezing point depression constant of water is 1.86 ºC/m.

A solution made by dissolving 150.0 g of an unknown compound in 425.0 mL of benzene to make a solution which has a freezing point 18.6 °C lower than that of pure benzene. Kf for benzene is 5.12 °C/m and the density of benzene is 0.877 g/mL.     What was the molality of the solution?   How many moles of the unknown compound were dissolved in the solution?   What is the molar mass of the unknown compound?