Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Chemistry 09-106: Modern Chemistry II Lecture Notes E: Thermodynamics II, Lecture notes of Thermodynamics

These are lecture notes on Thermodynamics II for the course Chemistry 09-106: Modern Chemistry II at Carnegie Mellon University. The notes cover topics such as biological energy storage, criteria for spontaneous reactions, and Gibbs Free Energy. The notes include equations and concepts related to bond enthalpies, ∆H, and ∆G. The notes also cover driving forces for reactions, such as enthalpy and entropy. The notes include examples of reactions and their associated ∆H values.

Typology: Lecture notes

Pre 2010

Uploaded on 05/11/2023

aarti
aarti 🇺🇸

4.5

(8)

224 documents

1 / 5

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
Chemistry 09-106: Modern Chemistry II Carnegie Mellon University
Lecture Notes E: Thermodynamics II Distributed on: Wednesday, January 26, 2005 Page 1 of 5
Lecture Notes E: Thermodynamics II
1) Biological energy storage
Concept
Based on bond enthalpies, what would you predict H to be for the above reaction?
a) H<0 b) H=0 c) H>0 d) can’t tell from information given
Concept
Which of the following must be true, based on the experimental H
a) The bonds (OP and OH) are stronger in ATP and water, than in ADP and phosphoric acid
b) The bonds (OP and OH) are weaker in ATP and water, than in ADP and phosphoric acid
Enzyme
H = -20.92kJ/mol
pf3
pf4
pf5

Partial preview of the text

Download Chemistry 09-106: Modern Chemistry II Lecture Notes E: Thermodynamics II and more Lecture notes Thermodynamics in PDF only on Docsity!

Lecture Notes E: Thermodynamics II

1) Biological energy storage

Concept Based on bond enthalpies, what would you predict ∆H to be for the above reaction? a) ∆H<0 b) ∆H=0 c) ∆H>0 d) can’t tell from information given

Concept Which of the following must be true, based on the experimental ∆H a)b) The bonds (OP and OH) are stronger in ATP and water, than in ADP and phosphoric acidThe bonds (OP and OH) are weaker in ATP and water, than in ADP and phosphoric acid

Enzyme

∆H = -20.92kJ/mol

2) Criteria for spontaneous reactions ∆Hfo^ (H 2 O(l) ) = -285.83 kJ/mol ; ∆Hfo^ (CO 2 (g)) = -393.51 kJ/mol; ∆Hfo^ ( MgO(s) ) = -601.70 kJ/mol Mg + ½ O 2 Æ MgO ∆H= -601.7 kJ/mole Mg + ½ CO 2 Æ MgO + C ∆H= -404.94 kJ/mole

Ba(OH) 2. 8H 2 O(s) + 2NH 4 Cl (^) (s) Æ 2 NH 3 (aq) + 10 H 2 O (^) (l)+ BaCl (^2) (aq) ∆H > 0

3) Gibbs Free Energy ∆G = ∆H – T∆S A process is spontaneous if ∆G < 0 Two driving forces for reactions: Enthalpy driven: ∆H < Entropy driven: ∆S > 0

5) Sign of ∆ S for some common processes

Concept What is the sign of ∆S for the following processes a) ∆S > 0, S increases b) ∆S < 0, S decreases Solid Æ Liquid

Liquid Æ Gas

N reactantsN < M Æ M productsCO 2 (g) Æ^ CO^ (g) + ½ O 2 (g)

N > M H 2 C=CH 2 (aq) + Br (^2) (aq) Æ H 2 BrC-CBrH 2 (aq)

Break a bond

NaCl (^) (s) Æ Na + (aq) + Cl - (aq)

Desorption from a surface

Elongate a polymer molecule