Behaviour of Gas

Gas Law’s

1. Boyle's law

At constant temperature, the volume of a definite mass of a gas is inversely proportional to pressure.

        V α 1/p (at constant T) or, V = K.1/p
        pV= K (where K is a constant)
        p₁V₁ = p₂V₂

2. Charle's law

At constant pressure, the volume of a definite mass of a gas is directly proportional to absolute temperature.

        V α T (at constant p) or, V = K.T
        V/T = k
        V₁ /T₁ = V₂ / T₂

3. Gay-Lussac's law

At constant volume, the pressure of given mass of a gas is directly proportional to the temp in Kelvin.

        p α T (at constant V) or, p= K . T
        or, p/T = K
        p₁ / T₁ = p₂ / T₂

4. Avogardo's gas law

At constant temperature and pressure the volume of a gas is directly proportional to the number of molecules.
        V α n (at constant T & p)

5. Ideal gas equation

pV = nRT is called ideal gas equation.
Where,
        p = Pressure,
        V = volume
        n = number of mole
        T = temperature in Kelvin.
        R = gas constant
            = 0.0821 lit atm K^-1 mol^-1
            = 8.314 JK^-1 mol^-1
            = 1.987 cal K^-1 mol^-1

6. S.T.P. & N.T.P.

S.T.P. — Standard temperature and pressure
N.T.P. — Normal temperature and pressure

At S.T.P., for 1 mole gas
V= 22.4 litre = 22400 ml
p = 1 atm = 76 cm of Hg = 760 mm of Hg T= 273 K