Question

A sample of an unknown liquid is vaporized in a flask having a volume of 298 mL at 100.0°C. The vapor has a mass = 0.687 g, and exerts a pressure = 775 torr. Calculate the molecular weight of the unknown liquid.​

Answer 1

69.196

Step-by-step explanation:

using ideal gas equation

• PV= nRT
• n= mass/molar mass
• PV=mass/molar mass x RT
• R = 62.364LTorrmol-¹k-¹
• make molar mass subject of formula
• m.m=(massxRT)/PV
• m.m = (0.687 x 62.364 x373)/(775 x 0.298)
• m = 69.196