Question

When 4.70 g of a nonelectrolyte solute is dissolved in water to make 935 mL of solution at 28 °C, the solution exerts an osmotic pressure of 943 torr. What is the molar concentration of the solution?How many moles of solute are in the solution?What is the molar mass of the solute?

Answer 1

The molar concentration = 0.05 M

There are 0.04675 moles solute

The molar mass of the solute is 100.53 g/mol

Step-by-step explanation:

Step 1: Data given

Mass of the nonelectrolyte solute = 4.70 grams

Volume of water = 935 mL

Temperature = 28 °C

osmotic pressure = 943 torr

Step 2: The osmotic pressure can be given as:

π = MRT

⇒ with π = the osmotic pressure = 943 torr

⇒ with M = the molarity of the solution

⇒ with R = the ideal gas constant = 0.08206 (L atm)/(mol K)

⇒ with T = the temperature = 28°C = 301 Kelvin

943 torr = 943 mmHg = 1.24 atm

π = MRT

1.24 = M*0.08206*301

M = 0.05 M

2) Calculate number of moles

Number of moles = Molarity * volume

Number of moles = 0.05 * 0.935L

Number of moles = 0.04675 moles solute

3) Calculate molar mass:

4.70g / 0.04675 mol = 100.53 g/mol

The molar mass of the solute is 100.53 g/mol