ACS Physical Chemistry: Thermochemistry Practice Test

The kinetic energy of gas particles is indeed proportional to the absolute temperature of the gas. According to the kinetic molecular theory, as the temperature of a gas increases, the kinetic energy of its particles also increases. This relationship can be mathematically expressed by the equation \( KE = \frac{3}{2} k T \), where \( k \) is the Boltzmann constant and \( T \) is the absolute temperature measured in Kelvin.

This means that at higher temperatures, gas particles move more rapidly, and their average kinetic energy increases accordingly. Conversely, at lower temperatures, the kinetic energy decreases. This principle is fundamental in understanding the behavior of gases under various thermal conditions and helps explain phenomena such as gas expansion, pressure changes, and the relationship between temperature and velocity of gas particles.

In the context of the other answer options, while volume and temperature do play roles in gas laws, the kinetic energy's direct proportionality to absolute temperature is the key concept here, highlighting the intrinsic energy associated with the motion of gas particles. Additionally, kinetic energy is not constant for all gases; it varies with temperature and could differ among gases depending on their respective temperatures and masses.