The ideal gas law is derived from the combination of Charles's law and Boyle's law and Avogadro's law. Charles's law states that "At constant pressure, the volume is directly proportional to temperature". It can be written as,
VαT( const.
P) Boyle's law states that "PV is constant at constant temperature". It can be written as,
PV= constant
Avogadro's law states that "An equal volume of all gases under the same conditions of temperature and pressure contains an equal number of molecules". It can be written as,
N1=N2 By combining the above three laws, the ideal gas equation can be written as,
PV=nRT The ideal gas equation helps to conclude the fact that the volume of a gas depends on temperature, pressure, and the number of moles present in it. Let us have two gases of different volume, pressure, and temperature. The ideal gas equation for twodifferent gas can be written as.
P1V1=nRT1.......(1) P2V2=nRT2......(2) Dividing equation (1) and (2), we get,
⇒= Since
R is gas constant and let us assume that the number of moles is the same for both gases.
⇒= Thus, the correct gas equation is
=