HC Verma Chapter 23 Problem 46

Problem

N=2e24 diatomic molecules at 500 K. Total internal energy?

Key Concepts

U=(5/2)Nk_B T for diatomic

Solution

U=2.5x2e24x1.38e-23×500=3.45e4 J

Answer

3.45 x 10^4 J

Concept Check

Verify: n=3.32 mol, U=(5/2)(3.32)(8.314)(500)=34524 J.

Common Mistakes

Using f=3 for diatomic.

Practice Tip

f=5 for diatomic at moderate T.