Question

The autoignition of both ethanol and octane occurs at 363 oC. Which gas sample contains the gas molecules that have a greater average kinetic energy

Answer 1

See explanation

Step-by-step explanation:

At the same temperature, the average kinetic energy of gases depends on the molecular mass of the gas. Hence, given a particular temperature, lighter molecules travel faster on the average than heavier molecules.

Considering ethanol and octane, The molar mass of ethanol is 46.07 g/mol while the molar mass of octane is 114.23 g/mol. Hence, ethanol has a greater average kinetic energy than octane at the same temperature.