Chemistry OWLV2

Question

An aqueous solution of 11.10 g of catalase, an enzyme found in the liver, has a volume of 1.00 L at 27°C. The solution's osmotic pressure at 27°C is

found to be 0.827 torr. Calculate the molar mass of catalase.

Answer 1

π - iMRT

π = osmotic pressure = 0.827 torr

i = van't Hoff factor = 1 for catalase (a non electrolyte)

M = molarity of catalase = moles/L = ?

R = gas constant = 62.36 Ltorr/Kmol (it is 0.0821 Latm/Kmol if you want to change torr to atm)

T = temperature in Kelvin = 27C + 273 = 300K

M = π /(i)(R)(T) = 0.827 / (1)(62.36)(300)

M = moles / L = 4.42x10^-5 moles / L

Since we have 1 L, we have 4.42x10^-5 moles of catalase

Molar mass = g / moles = 11.10 g / 4.42x10^-5 moles

Molar mass = 251,131 g / mole (not corrected for sig. figs.)