Heat is supplied to a diatomic gas at constant pressure. Then the ratio of Q : U : W is _______.

Step-by-step solution

For a diatomic gas, the number of degrees of freedom is f = 5 . The molar heat capacity at constant volume is C_v = f 2 R = 5 2 R . The molar heat capacity at constant pressure is C_p = C_v + R = 7 2 R . At constant pressure, the heat supplied is Q = nC_p T = n ( 7 2 R ) T . The change in internal energy is U = nC_v T = n ( 5 2 R ) T . The work done by the gas is W = nR T = n ( 2 2 R ) T . The ratio Q : U : W is 7 2 : 5 2 : 2 2 = 7 : 5 : 2 . Answer: 7 : 5 : 2