sy24_nov26_07hc

# sy24_nov26_07hc - The micro-macro connection Kinetic theory...

This preview shows pages 1–3. Sign up to view the full content.

1 The micro-macro connection Kinetic theory connects the micro- and macroscopic aspects of systems. It relates the macroscopic properties of a system to the motion and collisions of its atoms and molecules. Average p and T. What we call temperature T is a direct measure of the average translational kinetic energy What we call pressure p is a direct measure of the number density of molecules, and how fast they are moving ( v rms ) v rms = v 2 ( ) avg = 3 k B T m p = 2 3 N V ε avg T = 2 3 k B avg The average kinetic energy of the molecules of an ideal gas at 10°C has the value K 10 . At what temperature T 1 (in degrees Celsius) will the average kinetic energy of the same gas be twice this value, 2K 10 ? T 1 = 20°C T 1 = 293°C T 1 = 100°C The molecules in an ideal gas at 10°C have a root-mean-square (rms) speed v rms . At what temperature T 2 (in degrees Celsius) will the molecules have twice the rms speed, 2v rms ? T 2 = 859°C T 2 = 20°C T 2 = 786°C Kinetic energy of a gas

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

View Full Document
2 Degrees of freedom , or modes of energy storage into the system, can be: • translational for a monoatomic gas (translation along x, y, z axes, energy stored is only kinetic) • rotational for a diatomic gas (rotation about x, y, z axes, energy stored is only kinetic) • vibrational for a diatomic gas (two atoms joined by a spring-like molecular bond vibrate back and forth, both potential and kinetic energy are stored in this vibration) degrees of freedom or “modes”
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 10/30/2011 for the course PHYS 207 taught by Professor Winnokur during the Spring '06 term at University of Wisconsin.

### Page1 / 6

sy24_nov26_07hc - The micro-macro connection Kinetic theory...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online