Summary:
- Charles’s law states that the volume of a given mass of gas varies directly with the absolute temperature of the gas when pressure is kept constant.
- As a container of confined gas is heated, its molecules increase in kinetic energy and push the movable piston outward.
- The Kelvin scale must be used because zero on the Kelvin scale corresponds to a complete stoppage of molecular motion.
- The direct relationship will only hold if the temperatures are expressed in Kelvin.
- The relationship can be used to compare changing conditions for a gas.