A physician studying a mutant, hemoglobin, blood protein dissolves 0.0215 grams of this protein in water at 5.0 ° C to make 1.50 mL of solution. The osmotic pressure of this solution is 0.00475 atm. What is the molar mass of this protein?

Question

Quizplus · Accepted Answer

To find the molar mass of the protein, we can use the formula for osmotic pressure: $\pi = \frac{n}{V}RT$, where $\pi$ is the osmotic pressure, $n$ is the number of moles of solute, $V$ is the volume of the solution in liters, $R$ is the ideal gas constant (0.0821 L·atm/(K·mol)), and $T$ is the temperature in Kelvin. First, convert the temperature to Kelvin: $5.0 °C + 273.15 = 278.15 K$. Then, rearrange the formula to solve for $n$: $n = \pi V / RT$. Substitute the given values: $n = (0.00475 atm)(0.0015 L) / (0.0821 L·atm/(K·mol) \cdot 278.15 K)$. Solving for $n$ gives the number of moles of the protein. Finally, to find the molar mass, divide the mass of the protein by the number of moles: $Molar Mass = 0.0215 g / n$. Calculating with the given numbers leads to a molar mass that matches choice B.

A Physician Studying a Mutant, Hemoglobin, Blood Protein Dissolves 0