Question

Bovine serum albumin (BSA) is a biochemically useful protein. A 0.273 gram sample of bovine serum albumin is dissolved in water to make 0.157 L of solution, and the osmotic pressure of the solution at 25 °C is found to be 0.650 mbar. Calculate the molecular mass of bovine serum albumin.

Answer 1

Calculate the molecular mass of bovine serum albumin

.Π = MRT equation and use it to calculate molar mass M = m/MM where M = molarity ,

m= mass in grams

MM = molar mass

and as Π = MRT so

Π = m RT/V(MM)

rearrangment given an equation for molar mass:

MM = mRT/ ΠV  

Step 1 : Collecting all necessary datas required for the equation:

m_solute = 0.273 g , R=0.082 L atm/mol K ,T = 25 c + 273 = 298 K, Π = O.650m bar

Step 2: Convert osmotic pressure given in MILLIBAR TO atm

0.650 mbr =0.000641

Step 3: Switch all the datas in the desired equation to find the molar mass:

MM = mRT/ΠV = 0.273g * 8.206 x 10-2 L atm/molK* 298 K / 0.000641atm*0.157L

molarmass = 1,635.1290kg/mole