Question

A solution of 1.8274g of a polypeptide in 274mL of a aqueous solution has an osmotic pressure at 31.40 degrees C of 2.012 mmHg. The approximate molecular weight of this polymer is _____ g/mol.

Answer 1

Answer: Hence, the approximate molecular weight of the poymer is 64106 g/mol

Step-by-step explanation:

`\pi=CRT`

where,

`\pi` = osmotic pressure of the solution = 2.012 mm Hg = 0.0026 atm

i = Van't hoff factor = 1 (for non-electrolytes)

Mass of solute (polypeptide) = 1.8274 g

Volume of solution = 274 mL

R = Gas constant =
`0.0821Latm/Kmol`

T = temperature of the solution =
`31.40^0C=(273+31.40)K=304.4K`

Putting values in above equation, we get:

`0.0026=(1.8274 g* 1000)/(M* 274ml)* 0.0821* 304.4`

`M=64106g/mol`

Hence, the approximate molecular weight of the poymer is 64106 g/mol