Page 1 of 1

Entropy

Posted: Tue Feb 28, 2017 4:28 pm
by Imani Johnson 1H
Explain this to me conceptually,

how can you determine the sign of entropy when just given a reaction and no numbers? For example, the midterm gives the rxn: CO2(g)+H2O(l)-->H2CO3(aq).

How do you go about this?

Re: Entropy

Posted: Tue Feb 28, 2017 4:33 pm
by Mimi Lec 2H
Solids have lower molar entropy than liquids, and liquids have lower molar entropy of gases. In the gas phase, a compound has the highest molar entropy. I think there will be a decrease in entropy for this equation, because of the conversion of a gas and a liquid which have high molar entropy, into an aqueous solution.

Re: Entropy

Posted: Tue Feb 28, 2017 6:44 pm
by Chem_Mod
Also, when the number of molecules decreases, translational and rotational degrees of freedom are converted to vibrational degrees of freedom, which contribute less to entropy, and therefore entropy decreases.