If the volume of a confined gas is constant, then the absolute pressure is:

The statement that absolute pressure is directly proportional to absolute temperature when the volume of a confined gas is constant is rooted in the gas laws, specifically the ideal gas law. According to this law, the relationship can be described by the equation PV = nRT, where P is the pressure, V is the volume, n is the amount of gas in moles, R is the universal gas constant, and T is the absolute temperature in Kelvin.

When the volume (V) is held constant, the equation simplifies to P = (nR/V)T. In this case, as the absolute temperature (T) increases, the pressure (P) must also increase in direct proportion. This means that if the temperature rises, the kinetic energy of the gas molecules increases, leading to more frequent and forceful collisions with the container walls, which results in a higher pressure. Therefore, the relationship is directly proportional.

Understanding this connection is crucial for any scenarios involving gas behavior under varying temperature conditions, while keeping the volume constant. This foundational concept is essential in fields such as thermodynamics and vehicle engine operations, where pressure, volume, and temperature interact closely.