Retailers purchase gasoline by weight so they get a constant amount of gasoline per dollar (as long as the price is constant). We buy gasoline by volume. The enthalpy of combustion of 1.00 L of gasoline is -3.539 x 10⁴ kJ at 15.6^oC when gasoline has a density of 0.73722 g/mL. What would the enthalpy of combustion of 1.00 L of gasoline be at 32.2^oC when gasoline has a density of 0.72210 g/mL?

Question

Quizplus · Accepted Answer

The enthalpy of combustion per liter of gasoline changes with its density because the mass of gasoline per liter changes. At 15.6°C, the density is 0.73722 g/mL, and at 32.2°C, it is 0.72210 g/mL. The decrease in density means less mass of gasoline per liter at the higher temperature, leading to a lower absolute value of enthalpy of combustion for the same volume.

Retailers Purchase Gasoline by Weight So They Get a Constant