## Chemistry and Chemical Reactivity (9th Edition)

Osmotic pressure: $\Pi=cRT\rightarrow c=(3.17/760)\ atm\div(0.082\ mol.L/atm.K\times 298\ K)=1.707\times10^{-4}\ mol/L$ Number of moles: $1.707\times10^{-4}\ mol/L\times 0.1\ L=1.707\times10^{-5}\ mol$ Molar mass: $5.00\times10^{-3}\ g\div1.707\times10^{-5}\ mol=292.92\ g/mol$ In one mol of this substance: $n_C\times12.01/292.92=73.94/100\rightarrow n_H=18.03\approx18$ $n_H\times1.01/292.92=8.27/100\rightarrow n_H=23.98\approx24$ $n_{Cr}\times52.00/292.92=17.19/100\rightarrow n_{Cr}=1.00\approx1$ Empirical and molecular formula of the compound: $C_{18}H_{24}Cr$