# Problem: The vapor above a mixture of pentane and hexane at room temperature contains 35.5% pentane by mass. What is the mass percent composition of the solution? Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature.

###### FREE Expert Solution

Take 100 g basis for the mass of vapor:

mass pentane = 35.5g

mass hexane = 64.5g

Convert these values to mol using their molecular weights:

Pentane

M = 72.15 g/mol

Hexane:

M = 86.18 g/mol

100% (177 ratings) ###### Problem Details

The vapor above a mixture of pentane and hexane at room temperature contains 35.5% pentane by mass. What is the mass percent composition of the solution? Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature.

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