Question

β-Galactosidase (β-gal) is a hydrolase enzyme that catalyzes the hydrolysis of β-galactosides into monosaccharides. A 0.474 gram sample of β-galactosidase is dissolved in water to make 0.144 L of solution, and the osmotic pressure of the solution at 25 °C is found to be 0.701 mbar. Calculate the molecular mass of β-galactosidase.

I tried this
molar mass = (mass RT) / P(volume)
molar mass = 0.474 g (83.145 L·mbar/molK) (298K) / 0.144 L = 8.16X10^4 g/mol
but it was incorrect. please explain what im doing wrong?

Answer 1

pi = MRT
pi = osmotic pressure. I would convert the mbar to atm.
M = molarity in mols/L
R = 0.08206
T = 273 + C = ?
Solve for M. Then M = mols/L. You know M and and L, solve for mols.
Then mol = grams/molar mass. You know mols and grams, solve for molar mass. Post your work if you get stuck.