## Chemistry and Chemical Reactivity (9th Edition)

In 1 kg of the solution: Number of moles of solute: $(2/100\times 1000)g\div256.77\ g/mol=0.078\ mol$ Molality: $m=0.078\ mol\div 0.98\ kg=0.079\ m$ Freezing point depression: $\Delta T_f=iK_fm\rightarrow i=-0.237^{\circ}C\div(-1.86^{\circ}C/m\times 0.079\ m)=1.60$ There are 1.6 moles of ions in solution per mole of compound.