1.80 g of solute A was dissolved in 62.5 cm³ of ethanol and freezing point of the solution was found to be 155.1 K. The molar mass of solute A is g mol⁻¹.

[Given: Freezing point of ethanol is 156.0

Question

1.80 g of solute A was dissolved in 62.5 cm³ of ethanol and freezing point of the solution was found to be 155.1 K. The molar mass of solute A is  g mol⁻¹.

[Given: Freezing point of ethanol is 156.0 K. Density of ethanol is 0.80 g cm⁻³. Freezing point depression constant of ethanol is 2.00 K kg mol⁻¹]

Canvas Classes · Accepted Answer

Strategy:
 Calculate the freezing point depression, find the mass of the solvent (ethanol) from its volume and density, determine the molality, and finally solve for the molar mass of the solute.

Step 1: Calculate

Step 2: Find the mass of the solvent (ethanol)
Volume = 62.5 cm³, Density = 0.80 g/cm³.

Step 3: Calculate the molality ()
.

Step 4: Determine the molar mass ()
Moles of solute = .

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