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 described by Charles's Law. This law articulates that, when pressure is held constant, the volume of a given mass of gas increases as the temperature increases, and likewise, when the temperature decreases, the volume also decreases.

Mathematically, Charles's Law can be expressed as ( V \propto T ) (when pressure is constant), which means if the temperature in Kelvin doubles, the volume will also double, provided that the pressure remains unchanged. This relationship emphasizes the significance of absolute temperature, which is measured in Kelvin, as opposed to Celsius or Fahrenheit.

Understanding Charles's Law is essential in contexts such as understanding how balloons expand in warmer air or how gas behaves under different temperature conditions. The other laws mentioned pertain to different relationships or characteristics of gases, focusing on pressure-volume relationships (Boyle's Law), diffusion of gases (Graham's Law), or the total pressure of a gas mixture (Dalton's Law), which do not relate to the volume-temperature relationship defined by Charles's Law.