Question

A one liter of solution of 2.5g of polystyrene in benzene has an osmotic pressure of 4.5x10^-2 atm at 50C. Calculate molar mass of polystyrene

Answer 1

\[\Pi =MRT\] is what to use but i get a funky answer every time

Answer 2

you have to substitute \(n=\dfrac{m}{M}\) into \(M=\dfrac{n_{solute}}{L_{solution}}\)

Answer 3

Is this right? doesnt seem right

\[M=\frac{ R *T }{ \Pi } \rightarrow M= 1.7x10^-3\]
\[1.7x10^-3=\frac{ xmol }{ 1L } \rightarrow 1.7x10^-3 mol\]
\[2.5g=\frac{ 1.7x10^-3mol }{ molar mass } = 4.25x10^-3 \]

Answer 4

in the last step it should be: \(1.7*10^{-3}\;mol=\dfrac{2.5\;g}{M}\rightarrow M=\dfrac{2.5\;g}{1.7*10^{-3}\;mol}\)

Answer 5

so is that 1470g/mol or 1.5x10^3 g/mol?

Thank you so MUCH for your help!

Answer 6

1470

Answer 7

no problem dude