2011 Q1C heat capacity, residual entropy

Boltzmann Equation for Entropy:

Moderators: Chem_Mod, Chem_Admin

Posts: 16
Joined: Fri Sep 26, 2014 2:02 pm

2011 Q1C heat capacity, residual entropy

Postby 204301116 » Thu Mar 12, 2015 4:52 pm

Can someone please explain these to me?
Thank you
chem 3.jpg

Niharika Reddy 1D
Posts: 127
Joined: Fri Sep 26, 2014 2:02 pm

Re: 2011 Q1C

Postby Niharika Reddy 1D » Thu Mar 12, 2015 5:40 pm

Heat capacity increases with molecular complexity. As more atoms are present in a molecule, there are more possible bond vibrations that can absorb added energy. In addition to having more atoms, ethane has a C-C single bond, which allows it to have rotational freedom, whereas ethene has a C-C double bond that makes it more rigid since double bonds don't allow rotation.

NO has 2 distinguishable microstates (NO and ON) whereas BF3 is indistinguishable when the fluorine atoms exchange places. Residual entropy indicates using S=kblnW, and the degeneracy (W) will be greater for NO than BF3, so the residual entropy of NO will be greater as well.

Return to “Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy”

Who is online

Users browsing this forum: No registered users and 1 guest