What is "combined gas law"

n. (context physics English) a combination of Boyle's law and Charles's law which states that the product of the volume and pressure of an ideal gas divided by its temperature is constant

The combined gas law is a gas law that combines Charles's law, Boyle's law, and Gay-Lussac's law. There is no official founder for this law; it is merely an amalgamation of the three previously discovered laws. These laws each relate one thermodynamic variable to another mathematically while holding everything else constant. Charles's law states that volume and temperature are directly proportional to each other as long as pressure is held constant. Boyle's law asserts that pressure and volume are inversely proportional to each other at fixed temperature. Finally, Gay-Lussac's law introduces a direct proportionality between temperature and pressure as long as it is at a constant volume. The inter-dependence of these variables is shown in the combined gas law, which clearly states that:

This can be stated mathematically as:

$$\qquad \frac {PV}{T}= k$$

where:

is the pressure

is the volume

is the temperature measured in kelvins

is a constant (with units of energy divided by temperature).

For comparing the same substance under two different sets of conditions, the law can be written as:

$$\qquad \frac {P_1V_1}{T_1}= \frac {P_2V_2}{T_2}$$

The addition of Avogadro's law to the combined gas law yields the ideal gas law.