Study Material, Chemistry, Gaseous State, Boyles law

Boyle's law

(1) In 1662, Robert Boyle discovered the first of several relationships among gas variables (P, T, V).

(2) It states that, “For a fixed amount of a gas at constant temperature, the gas volume is inversely proportional to the gas pressure.”

Thus, p ∞ 1/v at constant temperature and mass

or P = K/V (where K is constant)

or PV = K or P₁V₁ = P₂V₂ = K (For two or more gases)

(3) Graphical representation of Boyle's law: Graph between P and V at constant temperature is called isotherm and is an equilateral (or rectangular) hyperbola. By plotting P versus 1/V, this hyperbola can be converted to a straight line. Other types of isotherms are also shown below,

(4) At constant mass and temperature density of a gas is directly proportional to its pressure and inversely proportional to its volume. 

(5) At altitudes, as P is low d of air is less. That is why mountaineers carry oxygen cylinders.