# ch21 - The Big Ideas-Chapter 21(Serway and Beichner Physics...

• Notes
• 3

This preview shows pages 1–2. Sign up to view the full content.

The Big Ideas—Chapter 21 (Serway and Beichner, Physics for Scientists and Engineers, 5 th Edition) AJM:2/17/01 1 Section 1 The ideal gas law is the natural result of a very simple model of a gas (in which molecules behave like particles that undergo elastic contact collisions with walls and other molecules) and an interpretation of temperature as a measure of the average energy per molecule. In this model the pressure arises from the average force of the collisions between the molecules and the walls and is directly associated with the density and the average translational kinetic energy of the molecules. The ideal gas law then reveals temperature as a pure function of the average translational kinetic energy. With far more generality than is implied by the derivation of this simple model, the “equipartition theorem” says that, for a system in thermal equilibrium, every possible way in which a molecule can store energy (each so-called “degree of freedom”) will on average store an energy determined solely by the temperature. P simple model = 2 3 N V 1 2 mv 2 ( 29 T ideal gas = 2 3 k B 1 2 mv 2 ( 29 1 2 mv 2 = 3 2 k B T Energy per degreee of freedom = 1 2 k B T Section 2 The equipartition theorem allows us easily to determine the internal energy of an ideal gas since the value depends only on how many molecules there are and on how many ways each molecules can translate, rotate and/or vibrate.

This preview has intentionally blurred sections. Sign up to view the full version.

This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern