Question 390: Thermodynamics & KTG

Question

The specific heats, C
P
and C
V
of a gas of
diatomic molecules, A, are given (in units of
J mol
–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 :-

Accepted Answer

For A:
$${{{C_p}} \over {{C_v}}} = \gamma  = 1 + {2 \over f} = {{29} \over {22}}$$
It gives f = 6.3 $$ \approx $$ 6 (3 translational, 2 rotational and 1 vibrational)
For B:
$${{{C_p}} \over {{C_v}}} = \gamma  = 1 + {2 \over f} = {{30} \over {21}}$$
$$ 	herefore $$ f = 4.67 $$ \approx $$ 5  (3 translational, 2 rotational, no vibrational)

Answer

A is rigid but B has a vibrational mode

Answer

A has a vibrational mode but B has none

Answer

A has one vibrational mode and B has two

Answer

Both A and B have a vibrational mode each

Thermodynamics & KTG

The specific heats, C P and C V of a gas of diatomic molecules, A, are given (in units of J mol –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 :-

Choose the correct answer: