 S univ =  S sys +  S surr Must be ____ for spontaneity as dictated by… + …the Second Law of Thermodynamics  S surr =  H / T (at constant P) So that:

Slides:



Advertisements
Similar presentations
CHEMICAL THERMODYNAMICS
Advertisements

Chapter 16 Spontaneous processes –Occur without assistance –Fast or slow –Thermodynamics predicts if reactions will occur but only focuses on the initial.
Thermodynamics:Entropy, Free Energy, and Equilibrium
Spontaneous Processes
1 Gibbs Free Energy, G Multiply through by -T -T∆S univ = ∆H sys - T∆S sys -T∆S univ = change in Gibbs free energy for the system = ∆G system Under standard.
Chapter 17 Spontaneity, Entropy, and Free Energy The goal of this chapter is to answer a basic question: will a given reaction occur “by itself” at a particular.
CHAPTERCHAPTERCHAPTERCHAPTER 19. Under standard conditions — ∆G o sys = ∆H o sys - T∆S o sys free energy = total energy change for system - energy change.
Chapter The Austrian physicist Ludwig Boltzmann introduced a model to relate the total number of microstates (the multiplicity, W) to entropy (S).
Chapter 19 Chemical Thermodynamics
Chapter 19. Overview Spontaneous Processes Entropy Second Law of Thermo. Standard Molar Entropy Gibbs Free Energy Free Energy & Temp. & Equil. Const.
Thermodynamics B. Thermodynamics –Deals with the interconversion of heat an other forms of energy First Law: Energy can be converted from one form to.
Thermodynamics Chapter 19 Liquid benzene Production of quicklime Solid benzene ⇅ CaCO 3 (s) ⇌ CaO + CO 2.
Lecture 8: The Second and Third Laws of Thermodynamics Reading: Zumdahl 10.5, 10.6 Outline Definition of the Second Law Determining  S Definition of.
Lecture 7: The Second and Third Laws of Thermodynamics Reading: Zumdahl 10.5, 10.6 Outline –Definition of the Second Law –Determining  S –Definition.
Lecure 8: The Second and Third Laws of Thermodynamics Reading: Zumdahl 10.5, 10.6 Outline –Definition of the Second Law –Determining  S –Definition of.
Chemical Thermodynamics: Entropy, Free Energy and Equilibrium Chapter
Copyright McGraw-Hill 2009 Chapter 18 Entropy, Free Energy and Equilibrium.
Chemical Thermodynamics Chapter 19 (except 19.7!).
First Law of Thermodynamics Enthalpy -  H, HfHf Second Law Third Law Entropy  S, Free Energy GG Spontaneity n Chap 18. Thermodynamics and Equilibrium.
Chapter 19 Chemical Thermodynamics Lecture Presentation John D. Bookstaver St. Charles Community College Cottleville, MO © 2012 Pearson Education, Inc.
Chemical Thermodynamics The chemistry that deals with the energy and entropy changes and the spontaneity of a chemical process.
Energy Changes in Chemical Reactions -- Chapter First Law of Thermodynamics (Conservation of energy)  E = q + w where, q = heat absorbed by system.
Thermodynamics Chapter 20. Thermodynamics Prediction of whether change will occur No indication of timeframe Spontaneous: occurs without external intervention.
Daniel L. Reger Scott R. Goode David W. Ball Chapter 17 Chemical Thermodynamics.
Chapter 19 – Principles of Reactivity: Entropy and Free Energy Objectives: 1)Describe terms: entropy and spontaneity. 2)Predict whether a process will.
Chapter 16 Thermodynamics: Entropy, Free Energy, and Equilibrium
Chapter 19 Chemical Thermodynamics. First Law of Thermodynamics Energy cannot be created nor destroyed. Therefore, the total energy of the universe is.
Thermodynamics Chapter 18.
Chapter 20: Thermodynamics
In general, the more atoms in its molecules, the greater is the entropy of a substance Entropy is a function of temperature.
Introduction to Entropy by Mike Roller. Entropy (S) = a measure of randomness or disorder MATTER IS ENERGY. ENERGY IS INFORMATION. EVERYTHING IS INFORMATION.
A.P. Chemistry Spontaneity, Entropy, and Free Energy.
Ch. 16: Spontaneity, Entropy, and Free Energy 16.1 Spontaneous Processes and Entropy.
What is a spontaneous reaction? One, that given the necessary activation energy, proceeds without continuous outside assistance.
Entropy, Free Energy, and Equilibrium Chapter 18 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Entropy, Free Energy, and Equilibrium Chapter 19 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chemical Thermodynamics © 2009, Prentice-Hall, Inc. Topic 9 Chapter 18 Chemical Thermodynamics.
Chapter 19 Chemical Thermodynamics Lecture Presentation John D. Bookstaver St. Charles Community College Cottleville, MO © 2012 Pearson Education, Inc.
Chapter 17 Spontaneity, entropy and free energy. Spontaneous l A reaction that will occur without outside intervention. l We need both thermodynamics.
Spontaneity, Entropy and Free Energy. Spontaneous Processes and Entropy  First Law “Energy can neither be created nor destroyed" The energy of the universe.
Chapter 17. Thermodynamics: Spontaniety, Entropy and Free Energy
Chapter 19 Spontaneity, entropy and free energy (rev. 11/09/08)
System strives for minimum Free Energy. aA + bB cC + dD G0G0 rxn d  G 0 (D) f c  G 0 (C) f = [+] - b  G 0 (B) f a  G 0 (A) f [+] G0G0 rxn n 
Free Energy and Thermodynamics Chapter 17. A process is said to be spontaneous if it occurs without outside intervention. Spontaneity.
Second Law of Thermodynamics. Law of Disorder the disorder (or entropy) of a system tends to increase ENTROPY (S) Entropy is a measure of disorder Low.
A science that includes the study of energy transformations and the relationships among the physical properties of substances which are affected by.
Entropy, Free Energy, and Equilibrium
Entropy. 1 st Law of Thermodynamics Energy is neither ____________ nor ____________  The energy of the universe is constant  Energy just changes from.
Spontaneous Processes and Entropy First Law “Energy can neither be created nor destroyed“. The energy of the universe is constant. Spontaneous Processes.
Entropy. 1 st Law of Thermodynamics Energy is neither created nor destroyed –The energy of the universe is constant –Energy just changes from one form.
Free energy and Thermodynamics suroviec Spring 2014
Entropy, Free Energy, and Equilibrium Chapter 18 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PowerPoint.
A science that includes the study of energy transformations and the relationships among the physical properties of substances which are affected by.
Entropy, Free Energy, and Equilibrium Chapter 18 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Entropy, Free Energy, and Equilibrium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chemical Thermodynamics  2009, Prentice-Hall, Inc. First Law of Thermodynamics You will recall that energy cannot be created nor destroyed. Therefore,
Entropy, Free Energy, and Equilibrium Chapter 18 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
20-1 Due: CH 20 Connect - Take out Notes/POGIL Today: Solving Problems for Thermodynamics HW: Test on Wednesday Potluck Thursday.
Review Unit 7 (Chp 5,8,19): Thermodynamics (∆H, ∆S, ∆G, K) John D. Bookstaver St. Charles Community College St. Peters, MO  2006, Prentice Hall, Inc.
THERMODYNAMICS – ENTROPY AND FREE ENERGY 3A-1 (of 14) Thermodynamics studies the energy of a system, how much work a system could produce, and how to predict.
Energy Changes in Chemical Reactions -- Chapter First Law of Thermodynamics (Conservation of energy)  E = q + w where, q = heat absorbed by system.
A science that includes the study of energy transformations and the relationships among the physical properties of substances which are affected by.
http:\\academicstaff.kmu.ac.ir\alia sadipour...43 slides.
Thermodynamics the study of energy transformations and transfer THREE QUESTIONS to be addressed: 1. Will a reaction occur when two substances are mixed.
SPONTANEOUS REACTIONS. Spontaneity 1 st Law of Thermodynamics- energy of the universe is ________. Spontaneous Rxns occur without any outside intervention.
Presentation transcript:

 S univ =  S sys +  S surr Must be ____ for spontaneity as dictated by… + …the Second Law of Thermodynamics  S surr =  H / T (at constant P) So that:  S univ =  S sys -  H / T multiply both sides by –T and rearrange to get… Indicates the units of entropy: J/K

 S univ =  H - T  S  G Hess’s Law Organizational Energy 1 st Law of Thermo Change in Free Energy Put in values that can easily be calculated…  H° - T  S°=  G° This is called: Gibb’s-Helmholtz Equation Standard change in Enthalpy This is called:Standard change in Entropy This is called:Standard change in Free Energy Standard states: (s)- pure (l)- pure (g)- pure, 1 atm (aq)- 1M Elemental- stable form Can be measured from relative standard formation reactions Can be measured from absolute* entropy values

H 2 O (l) + Na 2 O 2 (s) + S (s) → NaOH (aq) + SO 2(g) 224 Use Hess’s Law to get  H°:  H° =  n  H f ° products -  n  H f ° reactants 2(-286 kJ) 2(-515 kJ) 0 kJ 4(-470 kJ) -297 kJ 2(70 J/K) 2(95 J/K) 32 J/K 4(50 J/K) 248 J/K At 25.0°C the following reaction occurs under standard state conditions  H° = kJ kJ  H° = -575 kJ Use absolute S values to get  S°:  S° =  nS° prod. -  nS° react.  S° = 448J/K J/K  S° = 86 J/K Use Gibbs-Helmholtz to get  G°:  G° =  H° - T  S°  G° = -575 kJ – [ (298 K) (86 J/K) (1 kJ/1000 J)]  G° = -600 kJ Redox Reaction: transfer of electrons!!!! O +4 oxidation -2 reduction -2 Spontaneous under standard conditions!

H 2 O (l) + Na 2 O 2 (s) + S (s) → NaOH (aq) + SO 2(g) 224 2(-237 kJ) 2(-451 kJ) 0 kJ 4(-419 kJ) -300 kJ At 25.0°C the following reaction occurs under standard state conditions Use stand.  G f ° values to get  G°:  G° =  n  G f ° prod. -  n  G f ° react.  G° = kJ kJ  G° = -600 kJ Use Gibbs-Helmholtz to get  G°:  G° =  H° - T  S°  G° = -575 kJ – [ (298 K) (86 kJ/K) (1 kJ/1000 J)]  G° = -600 kJ the same !!!!!

The Third Law of Thermodynamics… The entropy of a perfect crystal at Absolute Zero is zero. S = k log W Boltzmann’s Entropy Equation Number of microstates, called the multiplicity The Boltzmann Constant, x J/K