Pentane and hexane form solution of two volatile liquids. What is the vapor pressure at 25C of a mixture of 397 mL pentane (72.15 g/mol) and 435 mL hexane(86.18 g/mol)? The density of pentane is 0.626 g/mL and hexane is 0.655 g/mL. Standard vapor pressures at 25C are 514 mmHg for pentane and 124 mmHg for hexane.