Quiz5_sol - 7A-C/D Win 09 Quiz 5 DL Sec Last 6 digits ID #...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
7A -C/D Win 09 Quiz 5 DL Sec Last 6 digits ID # Name (Last, First) Grade Consider a piston containing 1 mole of diatomic H 2 gas (molecular weight = 2 g/mol) and 5 moles of monatomic Ar (atomic weight = 40 g/mol), with both gases initially at T = 300 K. The temperature remains low enough in all problems so that the vibrational modes of the H 2 remain completely frozen. The gases are always in equilibrium with each other, so they both have the same temperatures. 1a) Which gas has higher average molecular speed, or are they the same? Explain. Equipartition says each mode gets 1/2 kT energy. For molecular speed all that matters is how many translational KE modes each molecule has, and for either type of gas there are 3 KE trans modes per molecule and thus 3/2 kT of translational KE. But the argon has more mass per molecule than the hydrogen, so with the same KE per molecule the hydrogen has a greater average speed. 1b) If we increase the temperature by 20 K, which gas has a larger change in internal energy (
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/13/2010 for the course PHY 7A 56192 taught by Professor ? during the Winter '09 term at UC Davis.

Ask a homework question - tutors are online