A solution is prepared by dissolving 5.00 g of an unknown molecular solid in water to make 1.00 L of solution.The osmotic pressure of the solution is 1.61 atm at 25°C.What is the molar mass of the solute? (R = 0.0821 L.atm/mol.K)

Question

Quizplus · Accepted Answer

To find the molar mass of the solute, we need to use the equation for osmotic pressure:

π = MRT

where π is the osmotic pressure, M is the molarity, R is the gas constant, and T is the temperature in Kelvin.

We know the osmotic pressure (1.61 atm), the temperature (25°C = 298 K), and we can calculate the molarity:

M = moles of solute / liters of solution

We are given that we have 5.00 g of solute in 1.00 L of solution, so we need to convert grams to moles:

moles of solute = 5.00 g / molar mass

Now we can substitute in the values we know:

1.61 atm = (5.00 g / molar mass) * (0.0821 L.atm/mol.K) * 298 K / 1.00 L

Solving for the molar mass gives:

molar mass = 5.00 g / (1.61 atm * 0.0821 L.atm/mol.K * 298 K) = 76.0 g/mol

Therefore, the answer is C.

A Solution Is Prepared by Dissolving 5