Historically certain colligative properties - boiling point elevation, freezing point depression and the osmotic pressure- have been used to calculate the molecular mass. Of these three, osmotic pressure is the most sensitive and gives the best results. Molecular mass can be found according the following equation:
π = MRT
Where: π = osmotic pressure,
M = molarity of solution,
R = the ideal gas constant (L•atm/mol•K), and
T = Kelvin temperature.
Calculate its molecular mass at 23.6 degrees C, 0.500 L of a solution which is having the 0.302 grams of an antibiotic has an osmotic pressure of 8.34 mmHg.