Deduction of Gas Laws from Kinetic Gas equation

Deduction of Gas Laws from Kinetic Gas equation:

(i) Boyles Law:-

PV = (1/3) Mu2        (Kinetic gas equation)

or PV = (2/2) (1/3) Mu2 = 2/3) Kinetic Energy  [∵ (1/2) Mu2 = K.E]

so PV = (2/3) K.E —(i) [as Kinetic Energy ∝ Temperature K.E = kT (k → const.)

so PV = (2/3). k.T — (ii)

or PV = constant at const. T (Boyles Law)

(ii) Charles Law

From equation (ii)

As PV = (2/3) kT so (V/T) = (2/3). (k/P) —(iii)

So at constant pressure V/T = constant at constant P

(iii) Dalton’s law of partial pressure:-

PV = (1/3) mnu2 (kinetic gas equation) of two gases are enclosed in same vessel then

P1V = (1/3) m1 n1 u12 & P2 V = (1/3) m2 n2 u22

Or P = P1 + P2 = (1/3) (m1n1u12/V) + (1/3) m2 n2 u22

Or P = P1 + P2

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