lec27 - Last Time Disorder entropy, S Second Law The...

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

View Full Document Right Arrow Icon
1 Last Time • Disorder – entropy, S Second Law • The entropy S tends to increase • S can be increased by: – heating : increased mobility thus disorder – greater freedom : increased volume • Trends : S vapor > S liquid > S solid • S = 0 at absolute zero, T = 0 K – can be measured at other T’s and 1 atm, S m ° Chemical Reactions • Knowing S m °for all reactants and products, one can find Δ S r °for the entire reaction. reactants products • Defined just like reaction enthalpy: Δ S r °= Σ nS m °(products) - Σ nS m °(reactants) Δ S r °> 0, S increase : Δ S r °< 0, S decrease Total Entropy • Need to include surroundings – avoids trouble Δ S tot = Δ S + Δ S surr • Recall: U is transferred via heat – at constant pressure q = Δ H Δ S surr = – Δ H/T
Background image of page 1

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

View Full DocumentRight Arrow Icon
2 What About the System? • Rewrite total entropy Δ S tot = Δ S – Δ H/T • Define new parameter : Δ G = – T Δ S tot Δ G is called the Gibbs free energy Δ G = Δ H – T Δ
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/18/2012 for the course CHEM 2B taught by Professor Clemens during the Winter '08 term at UC Davis.

Page1 / 4

lec27 - Last Time Disorder entropy, S Second Law The...

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

View Full Document Right Arrow Icon
Ask a homework question - tutors are online