Question

Unleaded gasoline can be purchased with various octane ratings, typically 87 (regular), 88-90(mid-grade), and 91-94 (premium). The octane rating indicates how resistant the fuel is to engine knock. If a fuel cannot withstand compression without detonating from the heat of compression, it will cause engine knock. Engine knock is when small pockets of the mixed air and fuel ignites after the spark ignited the fuel-air mixture in the combustion chamber. This reduces engine efficiency and can result in damage to the engine.  

On a hot summer day (38°C), what is the vapor pressure of isooctane (torr)?

Isooctane (C₈H₁₈) enthalpy of vaporization = 35.8 kJ/mol

Isooctane boiling point = 98.2°C

Answer 1