Gasoline Is Primarily a Mixture of Hydrocarbons and Is Sold

Multiple Choice

Gasoline is primarily a mixture of hydrocarbons and is sold with an octane rating that is based on a comparison with the combustion properties of isooctane. Gasoline usually contains an isomer of isooctane called tetramethylbutane (C₈H₁₈) , which has an enthalpy of vaporization of 43.3 kJ/mol and a boiling point of 106.5C. Determine the vapor pressure of tetramethylbutane on a very hot summer day when the temperature is 38C.

A) 80.0 torr
B) 36.7 torr
C) 67.8 torr
D) 47.9 torr
E) 89.3 torr