Question

A solution containing 29.35 mg of an unknown protein per 28.0 mL solution was found to have an osmotic pressure of 3.50 torr at 34 ∘C.

What is the molar mass of the protein?

Answer 1

osmotic pressure=C*R*T

C is the concentration of the solute

R is universal gas constant =0.0821Lit atm mol^-1K^-1

T is temperature in kelvin

convert torr to atm one torr=1/760 atm

osmotic pressure=3.50/760 atm=C*0.0821*(34+273)

C=1.8271*10^-4 mol/litre

C=number of moles/volume in litres (volume=0.028L)

1.8271*10^-4 *0.028=number of moles

number of moles=5.11588*10^-6=(weight/molar mass) (weight=0.02935g)

molar mass=weight/number of moles=(0.02935/5.11588*10^-6)=5737 g/mole