Open Question
A solution containing 27.55 mg of an unknown protein per 25.0 mL was found to have an osmotic pressure of 3.22 torr at 25 °C. What is the molar mass of the protein?
Ch.13 - Solutions
Chapter 13, Problem 88
Is the question formulated correctly for calculating the freezing point and boiling point of each solution, assuming complete dissociation of the solute? For the following: a. 10.5 g FeCl3 in 1.50 * 10^2 g water b. 3.5% KCl by mass (in water) c. 0.150 m MgF2.
Verified step by step guidance1
<insert step 1> Determine the molality (m) of each solution. For FeCl3, calculate the number of moles of FeCl3 using its molar mass, then divide by the mass of water in kilograms. For KCl, use the given mass percentage to find the mass of KCl in 100 g of solution, then calculate molality. For MgF2, the molality is already given as 0.150 m.>
<insert step 2> Calculate the van't Hoff factor (i) for each solute, which represents the number of particles the solute dissociates into. For FeCl3, i = 4 (Fe^3+ and 3 Cl^-). For KCl, i = 2 (K^+ and Cl^-). For MgF2, i = 3 (Mg^2+ and 2 F^-).>
<insert step 3> Use the freezing point depression formula: \( \Delta T_f = i \cdot K_f \cdot m \), where \( K_f \) is the cryoscopic constant for water. Calculate \( \Delta T_f \) for each solution.>
<insert step 4> Use the boiling point elevation formula: \( \Delta T_b = i \cdot K_b \cdot m \), where \( K_b \) is the ebullioscopic constant for water. Calculate \( \Delta T_b \) for each solution.>
<insert step 5> Determine the new freezing and boiling points by subtracting \( \Delta T_f \) from the normal freezing point of water (0°C) and adding \( \Delta T_b \) to the normal boiling point of water (100°C).>
Related Practice
Open Question
Calculate the osmotic pressure of a solution containing 18.75 mg of hemoglobin in 15.0 mL of solution at 25 °C. The molar mass of hemoglobin is 6.5 x 10^4 g/mol.
Textbook Question
Calculate the freezing point and boiling point of each aqueous solution, assuming complete dissociation of the solute. c. 5.5% NaNO3 by mass (in water)
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Textbook Question
What mass of salt (NaCl) should you add to 1.00 L of water in an ice cream maker to make a solution that freezes at -10.0 °C? Assume complete dissociation of the NaCl and density of 1.00 g/mL for water.
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Textbook Question
Use the van't Hoff factors in Table 13.9 to calculate each colligative property: a. the melting point of a 0.100 m iron(III) chloride solution
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Open Question
Using the van’t Hoff factors in Table 13.9, calculate the mass of solute required to make each aqueous solution: a. a sodium chloride solution containing 1.50 * 10^2 g of water that has a melting point of -1.0 °C; b. 2.50 * 10^2 mL of a magnesium sulfate solution that has an osmotic pressure of 3.82 atm at 298 K; c. an iron(III) chloride solution containing 2.50 * 10^2 g of water that has a boiling point of 102 °C.