Question

Lysozmyne is an enzyme that breks bacterial cell walls. A solution containing 0.150g of this enzyme in 210ml of solution has an osmotic pressure of 0.217kPa at 25*C. What is the molar mass of Lysozmyne?

I cant find the chemical formula anywhere. I have used the osmotice pressure eq to get M=5.1*10^-5, but where do i go from there?

Answer 1

I couldn't find the formula either; however, that's what the problem is asking you to do.
pi = MRT
pi = 0.217 kPa x (1 atm/101.325 kPa) = ??
R = 0.08206
T = 298 K
I get something like 9 x 10^-5 M.
Then moles = M x L
moles = about 9 x 10^-5 x 0.210 L = xx
molar mass = grams/moles = 0.150/xx moles.
I get something like 8,000 for a molar mass. I did find a formula one place that gave C15H20O4 BUT no mention if this was a molecular formula or an empirical formula.

Answer 2

i thought pi was 0.217?
the answer in the text is 1.39*10^4g

Answer 3

pi is given in the problem as 0.217 kPa. I converted that to atm so I could use 0.08206 L*atm/mol*K for R. If you wish to use 0.217 kPa, then you must use 8.314 for R. In any event, you obtain 8.758 x 10^-5 M. How did you get 5.1 x 10^-5 M