The specific heats, C p and C v of a gas of diatomic molecules, A , are given (in units of J m o l - 1 K - 1 ) by 29 and 22 , respectively. Another gas of diatomic molecules, B , has the corresponding values 30 and 21 . If they are treated as ideal gases, then:

Step-by-step solution

For A : R = C p - C v = 29 - 22 = 7 C v = f R 2 ⇒ 22 = f × 7 2 ⇒ f = 44 7 = 6.3 ⇒ f ≈ 6 (5 rotational + translational, 1 vibrational) For B : R = C p - C V = 30 - 21 = 9 C v = f R 2 = 21 ⇒ f = 21 × 2 9 = 42 9 = 4.66 ≃ 5 ∴   f ≃ 5 (5 rotational + transitional, 0 vibrational)