Calculate the vapor pressure of ethanol, CH₃CH₂OH, in a water solution containing 80.0% ethanol by volume at 19.0°C. The vapor pressure of pure ethanol at 19.0°C is 40.0 Torr. The density of ethanol is 0.789 g·mL⁻¹ and the density of water is 1.000 g·mL⁻¹.