Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A flask holds of an ideal gas at . Its internal energy is . The molecules do not vibrate. Find the number of degrees of freedom of one molecule. Is the gas neon, carbon dioxide or methane? Take .
Each squared term in the energy of a molecule has on average. Translation gives 3 terms, rotation 2 (linear) or 3 (bent), and each active vibration 2.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The rule. . We want , so .
Step 2. Numbers. . Then .
Step 3. Which gas? means 3 ways to move and 3 ways to turn. The molecule is bent. It is methane.
Check. Neon would have , half as much.
Log in to join the discussion.
Loading…