According to the kinetic theory of gases, the average kinetic energy of gas molecules is proportional to which macroscopic measure?

The correct choice is temperature because, according to the kinetic theory of gases, the average kinetic energy of gas molecules is directly proportional to the temperature of the gas measured in Kelvin. This theory posits that as the temperature increases, the average kinetic energy of the gas molecules also increases, leading to more vigorous motion and more frequent collisions among the molecules.

Temperature acts as a measure of the thermal energy of the system, linking directly to the speed at which gas molecules are moving. Therefore, in a system where temperature rises, the molecules not only move faster, but their energy also increases as a result.

Other options, while related to gas behavior, do not directly correlate with the average kinetic energy in the same way. Pressure may change with molecular interaction and collision frequency but does not reflect kinetic energy alone. Volume relates to the space that gas occupies and can affect pressure but is not a measure of the kinetic state. Density pertains to mass per unit volume and, while influenced by temperature and pressure, does not capture the kinetic energy aspect directly. Thus, temperature remains the key measure of the kinetic energy of gas molecules.