Starting with the definition of osmotic pressure
Pi = -RT/V_ml * ln * (p_so*ln)/(p_1)^0
Derive the semi-empirical expression for a dilute real solution
Pi/C' = RT/M_2 + bC'
Where C' is the concentration expressed in (g solute)/(dm3 solution) and b is known as the interaction constant. Then use the semiempirical formula to determine the molar mass of inulin (C6H10O5)x from the following data at 200C.
C' (gsolute/dm3soln) 103.8 77.1 50.9 25.2
Pi (bar) 0.86 0.58 0.31 0.14
The key is to expand ln x in a Taylor series for x small and with x small the terms psol/P1o give only two ...
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