Open Question
Examine the structures of phenol and naphthol shown here and explain why phenol is so much more soluble in water at 25 °C (87 g/L) compared to naphthol (0.74 g/L).
Ch.13 - Solutions
Chapter 13, Problem 8
Calculate the freezing point and boiling point of a solution containing 7.55 g of ethylene glycol (C2H6O2) in 85.7 mL of ethanol. Ethanol has a density of 0.789 g/cm³.
Verified step by step guidance1
Calculate the molality of the solution by first determining the moles of ethylene glycol using its molar mass.
Convert the volume of ethanol to mass using its density, then convert this mass to kilograms.
Use the formula for molality: \( m = \frac{\text{moles of solute}}{\text{kilograms of solvent}} \).
Apply the freezing point depression formula: \( \Delta T_f = i \cdot K_f \cdot m \), where \( i \) is the van't Hoff factor (1 for ethylene glycol), and \( K_f \) is the freezing point depression constant for ethanol.
Apply the boiling point elevation formula: \( \Delta T_b = i \cdot K_b \cdot m \), where \( K_b \) is the boiling point elevation constant for ethanol.
Related Practice
Open Question
Use Henry’s Law to determine the molar solubility of helium at a pressure of 1.0 atm and 25 °C.
Open Question
You can purchase hydrochloric acid in a concentrated form that is 37.0% HCl by mass and that has a density of 1.20 g>mL. Describe exactly how to prepare 2.85 L of 0.500 M HCl from the concentrated solution.
Open Question
What is the required concentration (in percent by mass) for an aqueous ethylene glycol (C2H6O2) solution to have a boiling point of 104.0 °C?
Open Question
What is the boiling point of an aqueous solution with a vapor pressure of 20.5 torr at 25 °C? (Assume a nonvolatile solute.)
Textbook Question
Pick an appropriate solvent from Table 13.3 to dissolve each substance. State the kind of intermolecular forces that would occur between the solute and solvent in each case. a. motor oil (nonpolar) b. ethanol (polar, contains an OH group) c. lard (nonpolar) d. potassium chloride (ionic)