Question

A water molecule has three atoms (two hydrogen and one oxygen) with total energy $9RT$ ($3 \times 3k_B T N_A = 9RT$). Its specific heat is:

• A. R
• B. R
• C. R
• D. R

Hint:

Specific heat depends on the degrees of freedom. Molecules with vibrational and rotational modes have higher specific heat.

Answer 1

The Correct Option is D

The total energy of a molecule with three degrees of freedom is:
\[ E = 9RT \]
The specific heat is:
\[ C = \frac{\partial E}{\partial T} = 9R \]
This aligns with the degrees of freedom for rotational and vibrational contributions.