**Question**

**Establish the combined law of Boyle’s and Charle’s law.**

**Answer**

Let V be the volume of a given mass of gas at pressure P and temperature T (absolute),

From Boyle’s law,

V ∝ 1/P (m and T constant)

From Charle’s law,

V ∝ T (m and P constant)

By combining two laws we have,

V ∝ T/P or,

V = K T/P (Where K = proportionality constant)

or, PV = KT

or, PV = nRT

Where n is the number of moles of gas, R is the universal gas constant (0.08206 L·atm/mol·K)