Question

If 200 cm³ of an aqueous solution of a protein contains 1.26 g of protein, the osmotic pressure of the solution at 300K is found to be 2.57 × 10⁻³ atm.

Calculate the molar mass of protein.

(R = 0.0821 L atm K⁻¹ mol⁻¹)

Answer 1

Given:

mass of protein = 1.26 g

Volume of solution = 200 cm³ = 0.20 L

R = 0.0821 L atrn K⁻¹ mol⁻¹

T = 300K

Osmatic pressure, π = 2.57 × 10⁻³ atrn

To calculate molar mass of protein:

π = CRT = `("WRT")/("MV")`

M = `("WRT")/("πV")`

= `(1.26 xx 0.0821 xx 300)/(2.57 xx 10^-3 xx 0.2)`

= 60377 g mol⁻¹

Hence, the molar mass of protein is 60377 g mol⁻¹.