Question

A new non-electrolyte molecular is discovered. When 241 mg of the molecular is dissolved in 250.0 mL of water, it has an osmotic pressure of 0.072 atm at 25 oC.What is the molar mass of the molecular

Answer 1

Molar mass = 32.62g/mol

Step-by-step explanation:

Mass = 24mg

Volume = 250.0ml

Osmotic pressure = 0.072 atm

Temperature = 25 oC = 298 K (Converting to Kelvin temperature)

Mass concentration = Mass / Volume

Mass concentration = 24 mg / 250 ml = 0.096 mg/ml = 0.096 g / L

This means that in 1L, there are 0.096g of the non electrolyte.

Molar mass = Mass / Moles

Finding the Molarity using osmotic pressure and temperature

p = MRT

Where M = n / v

M = p / RT

M = 0.072 / (0.0821 L atm/mol K) (298K)

M = 0.072 / 24.4658

M = 0.002943M

Find the moles of solute from molarity by multiplying by the liters of solution. Since our calculation is base on 1L,

moles = Molarity * Volume

moles = 0.002943M * 1

moles = 0.002943 mol

Molar mass = Mass / Moles

Molar mass = 0.096g / 0.002943 mol

Molar mass = 32.62g/mol