Which law describes the relationship observed when a gas is maintained at a constant pressure while its volume varies in direct proportion to the change in absolute temperature?

The law that describes the relationship between gas volume and temperature when pressure is held constant is Charles's Law. This law states that the volume of a gas is directly proportional to its absolute temperature (measured in Kelvin) when the pressure is constant. This means that as the temperature of the gas increases, its volume will increase, and conversely, as the temperature decreases, the volume will decrease, assuming pressure remains unchanged.

In practical applications, this relationship allows engineers and scientists to predict how a gas will behave under varying temperature conditions at constant pressure, which is essential in various fields, including HVAC, meteorology, and even in operating engines.

While Boyle's Law deals with the relationship between pressure and volume at a constant temperature, and the Ideal Gas Law integrates pressure, volume, and temperature into a single framework, Avogadro's Law focuses on the volume of gas at constant temperature and pressure proportional to the number of moles of gas present. None of these directly capture the specific scenario of constant pressure with varying volume and temperature, making Charles's Law the correct reference.