Chapter 11

An aqueous solution containing 0.250 mole of $\mathrm{Q},$ a strong electrolyte, in $5.00\times {10}^2\mathrm{g}$ water freezes at $-{2.79}^{\circ }\mathrm{C}.$ What is the van't Hoff factor for $\mathrm{Q}?$ The molal freezing-point depression constant for water is ${1.86}^{\circ }\mathrm{C}\cdot \mathrm{kg}/\mathrm{mol}$ . What is the formula of $\mathrm{Q}$ if it is 38.68$\mathrm{\%}$ chlorine by mass and there are twice as many anions as cations in one formula unit of $\mathrm{Q}?$

Anthraquinone contains only carbon, hydrogen, and oxygen. When 4.80 $\mathrm{mg}$ anthraquinone is burned, 14.2 $\mathrm{mg}{\mathrm{CO}}_2$ and 1.65 $\mathrm{mg}{\mathrm{H}}_2\mathrm{O}$ are produced. The freezing point of camphor is lowered by ${22.3}^{\circ }\mathrm{C}$ when 1.32 $\mathrm{g}$ anthraquinone is dissolved in 11.4 $\mathrm{g}$ camphor. Determine the empirical and molecular formulas of anthraquinone.