ОХ188 The vapor pressure of ether at 300C equal to 648

ОХ188 The vapor pressure of ether at 300C equal to 648

188. The vapor pressure of ether at 300C equal to 648 mm Hg. Art. How many moles of the substance to be dissolved in 40 moles of ether to lower the vapor pressure at this temperature for 10 mm Hg. Art.?