Which law states that the volume of a gas is directly proportional to its temperature in Kelvin?

The statement that the volume of a gas is directly proportional to its temperature in Kelvin is a principle described by Charles's Law. This law indicates that if the pressure of a gas is held constant, an increase in temperature will result in an increase in the volume of the gas, and vice versa. The relationship can be mathematically expressed as V ∝ T, where V represents volume and T represents temperature in Kelvin.

This direct proportionality means that if the temperature of the gas increases, the volume will expand as the particles gain kinetic energy and move more vigorously. Conversely, if the temperature decreases, the volume will contract.

Other laws mentioned relate to different aspects of gas behavior. Boyle's Law concerns the relationship between pressure and volume when temperature is held constant; Graham's Law deals with the rates of diffusion of gases; and Dalton's Law pertains to the pressure exerted by a mixture of gases. Thus, Charles's Law is correctly identified as the principle that describes the relationship between the volume of a gas and its temperature in Kelvin.