Answer:
The osmotic pressure will allow us to calculate the molar mass of the substance:
π = iMRT
2.13 atm = (a) (x / 0.175 L) (0.08206 L atm / mol K) (298 K)
x = 0.015243 mole
2.04 g / 0.015243 mole = 133.83 g/mole
For your problem, let us calculate the amount of carbon and hydrogen. Then, by subtraction, we will check for oxygen.
carbon: 36.26 g x (12.011 g / 44.01 g) = 9.8959 g
hydrogen: 14.85 g x (2.016 g / 18.015 g) = 1.6618 g
oxygen: 22.08 minus (9.8959 + 1.6618) = 10.5223 g
Calculate moles of each element:
carbon: 9.8959 g / 12.011 /mol = 0.8239 mol
hydrogen: 1.6618 g / 1.008 g/mol = 1.6486 mol
oxygen: 10.5223 g / 15.999 g/mol = 0.657685 mol
Determine a molar whole number ratio:
carbon: 0.8239 / 0.657685 = 1.25
hydrogen: 1.6486 / 0.657685 = 2.5
oxygen: 0.657685 / 0.657685 = 1
Look at it like this:
carbon: 1.25 = 5/4 = 5
hydrogen: 2.5 = 10/4 = 10
oxygen: 1 = 4/4 = 4
C5H10O4
