Chapter 20: Thermodynamics
|
|
- Oliver Bradley
- 6 years ago
- Views:
Transcription
1 Chapter 20: Thermodynamics Thermodynamics is the study of energy (including heat) and chemical processes. First Law of Thermodynamics: Energy cannot be created nor destroyed. E universe = E system + E surroundings E universe = E system + E surroundings If E universe = 0, then E system = E surroundings The first law of thermodynamics explains the energy exchange between the system and surroundings. Does it explain the direction a reaction proceeds toward equilibrium? For systems under constant pressure and no work, H = E. Does the sign of H tell us the direction a reaction proceeds toward equilibrium? Let s try the Second Law of Thermodynamics. 1
2 Second Law of Thermodynamics: The total entropy (S) of a system and its surroundings increases for spontaneous reactions. A spontaneous reaction is one that occurs naturally under certain conditions without a continuous input of outside energy. Note: If a reaction is spontaneous in one direction, it will be nonspontaneous in the reverse direction. Consider the following diagram: When the valve is opened some of the gas particles move spontaneously into the other side as shown in B. Will all of the molecules spontaneously move back as depicted in A? In B of the diagram above, the gas particles occupy twice the volume thus the gas particles can exist in twice as many locations. Thus greater disorder. Disorder S disorder > S order, in other words, the entropy of disordered matter is greater than the entropy of ordered matter. Examples to consider: Ice melting disorder S system increases Water freezing order S system decreases 2
3 All processes occur spontaneously in the direction that increases the total entropy of the universe. Therefore, S universe > 0, S system + S surroundings > 0 Let s consider two rxns, one exothermic and one endothermic. 4 Fe (s) + 3 O 2(g) 2 Fe 2 O 3(s) + Heat Now, let s consider another reaction. 3
4 Ba(OH) 2. 8H 2 O (s) + 2 NH 4 NO 3(s) + Heat Ba 2+ (aq) + 2NH 3(g) + 2 NO 3 - (aq) + 10H 2 O (l) Therefore changes in entropy of the system and the surroundings must be important to the spontaneity of reactions. Third Law of Themodynamics: A perfect crystalline substance at 0 K has 0 entropy. Perfect means that all of the particles are flawlessly aligned in the crystal with no imperfections. Standard Molar Entropies (S o ) at 298 K are on pg A-5 of text. Units: J/mol-K Note: Standard Molar Enthalpies ( H o ) are also located on pg A-5. Let s Make Some Comparisons Temperature versus Entropy Copper metal T(K) S o (J/mol-K) What general statement can you make about this comparison? 4
5 Physical State Compared with Entropy Values Substance S o (J/mol-K) Ba (s) 62.5 Ba (g) Br 2(l) Br 2(g) C (s) 5.7 C (g)
6 Comparison of the Solid State with Aqueous Solution Substance Entropy (J/mol-K) NaCl (s) 72.1 NaCl (aq) AlCl 3(s) 167 AlCl 3(aq) -148 CH 3 OH (l) 127 CH 3 OH (aq) 132 Note: When gases are dissolved in liquids the system decreases in entropy. Explain. 6
7 Compare Molar Mass and Entropy Substance MW (g/mol) Entropy (J/mol-K) Cu Au Ag What general statement can you make about this comparison? Compare Compound Complexity with Entropy 7
8 Substance Entropy (J/mol-K) MgCO Na 2 CO C 2 H CH What general statement can you make about this comparison? Calculating the Change in Enthalpy of a Reaction Recall the equation: H o rxn= Σ n H o products Σ n H o reactants We can use a similar equation to calculate the change in entropy of a reaction. S o rxn= Σ ns o products Σ ns o reactants Problem Solving Calculate the change in entropy of the combustion of methane. H 2 O (g) CO 2(g) CH 4(g) O 2(g) S o (J/mol-K) Did the entropy of the system increase or decrease? What does this mean for the surroundings? 8
9 Entropy of the Surroundings In order for S universe to be increasing if S system decreases for a spontaneous reaction, then S surroundings must increase. Let s consider the following diagram. Exothermic Rxn Exothermic Rxn Endothermic Rxn Let s Talk Heat Exchange ( Η) If heat is lost to the surroundings, then the entropy of the surroundings should increase. If heat is gained by the surroundings, then the KE goes up and so does the entropy. 9
10 If heat is gained by the system (lost by the surroundings), the system becomes more disordered (entropy increases). Also, If the temperature of the surroundings is low, the particles are more ordered and a change in heat of the surroundings would have an even greater effect on the change in entropy. Then S surroundings is directly related to an opposite sign of H system, and inversely related to temperature at which the heat is transferred. Mathematically Speaking S surroundings is proportional to -q system S surroundings is proportional to 1/T S surroundings = -q system /T S surroundings = - H system /T So, calculate S surroundings for the combustion of methane at 25 o C from H fo values. H fo (CH 4 ) = kJ/mol, H fo (CO 2 ) = kj/mol, and H fo (H 2 O) = kJ/mol Using your information, calculate S universe for the combustion of methane. Did the entropy of the universe increase? 10
11 Entropy and Equilibrium What is the change in entropy of the universe for rxns at equilibrium? S universe = Equilibrium S surroundings + S system = S universe Thus, S surroundings = - S Equilibrium Problem Calculate the change in entropy for the following reaction: H 2 O (l) H 2 O (g) S(J/mol-K) K If the change in enthalpy is 40,700 J/mol at 373 K, what is the change in entropy of the universe? Entropy, Free Energy, and Work One criterion for spontaneity is Gibbs Free Energy ( G) Proof: S surroundings + S system = S universe S surroundings = - H system /T - H system /T + S system = S universe H system -T S system = -T S universe Given that: -T S universe = G universe H system - T S system = G universe 11
12 Gibbs Free Energy and Spontaneity If G < 0, The rxn is spontaneous If G > 0, the rxn is nonspontaneous If G = 0, the rxn is at equilibrium Note: G o fvalues are on page A-5. These values for an element in its most stable state are 0. Also, if a rxn has a particular value for G in one direction, it will be the same value with reversed sign in the opposite direction. Just like Η. ;) Problem Determine whether or not the following reaction is spontaneous. Use TWO methods and compare: (a) use only delta G values (kj/mol), (b) use delta H o f (kj/mol) and S o (J/mol-K) values 4 KClO 3(s) 3 KClO 4(s) + KCl (s) H o f S o G o f Most exothermic reactions are spontaneous. However, temperature will affect the T S factor of the equation: H system - T S system = G universe Therefore, reaction spontaneity can change with temperature. Example: At 298 K, G o = kJ, H o = kj, and S o = J/K for a reaction. (1) Is the rxn spontaneous at 298K? (2) If temperature is increased what happens to G o? (3) Assuming Η o and S o are constant with temperature, is the rxn spontaneous at 900. o C? 12
13 Crossover Temperature At what temperature does a reaction become spontaneous? + G o == - G o At some point G o equals 0 equil) Thus, H system - T S system = G universe H system - T S system = 0 H system = T S system or H system / S system = T crossover What is the crossover temperature for the previous problem? Problem: Determine if the following reaction is spontaneous at 298K. Also determine the crossover temperature. Cu 2 O (s) + C (s) 2 Cu (s) + CO (g) S o = 165 J/K and H o = 58.1 kj 13
14 Free Energy, Equilibrium, and Rxn Direction Recall, If G < 0, rxn is spontaneous, product favored, and Q is < K. If G > 0, rxn is nonspontaneous, reactant favored, and Q > K. If G = 0, rxn is at equilibrium and Q = K. Given that G o rxn is proportional to ln (Q/K) and their signs are identical for a given reaction, we have: G rxn = RT ln (Q/K) G rxn = RTln Q - RTln K If we set [ ] s = 1.00 M for sol ns and 1.00 atm for gases (std conditions), then, G o rxn = RTln 1 - RTln K Or G o rxn = - RTln K Note: K can be determined for any rxn at any temp if we know G o rxn 14
15 Problem Solving Determine the thermodynamic equilibrium constant at 25 o C for the following rxn: N 2 O 4(g) 2 NO 2(g) G o f (kj/mol) However, most reactions are not with 1.0 M solutions and/or 1.00 atm for gases, thus we also need to remember this form of the equation: G rxn = RT lnq - RT lnk Since G o rxn = -RT lnk G rxn = G o rxn+ RTlnQ The above relationship is very important to our next chapter, you will definitely see it again. 15
16 Problem Solving Consider the following reaction: 2 SO 2 (g) + O 2 (g) 2 SO 3 (g) G o rxn kj at 298K and kj at 973K. (a) Determine K eq at 298K. (b) Determine K eq at 973K. (c) If a vessel contains 0.500M SO 2, M O 2, and 0.100M SO 3 at 298K, what is G rxn? (d) Under the conditions in (c) which way would the reaction proceed? More Problem Solving Consider the reaction: N 2 (g) + 3H 2 (g) 2 NH 3 (g) S o (J/mol-K) H o (kj/mol) (a) Determine the equilibrium constants at 298 K and at 984 K. (b) What is the cross-over temperature for this reaction in Kelvin. (c) If, at 298K, a vessel contains 0.250M H 2, M N 2, and 12.9M NH 3, predict the direction the reaction will proceed at this temperature. 16
Chapter 19 Chemical Thermodynamics Entropy and free energy
Chapter 19 Chemical Thermodynamics Entropy and free energy Learning goals and key skills: Understand the meaning of spontaneous process, reversible process, irreversible process, and isothermal process.
More informationThermodynamics. Thermodynamically favored reactions ( spontaneous ) Enthalpy Entropy Free energy
Thermodynamics Thermodynamically favored reactions ( spontaneous ) Enthalpy Entropy Free energy 1 Thermodynamically Favored Processes Water flows downhill. Sugar dissolves in coffee. Heat flows from hot
More informationChapter 17.3 Entropy and Spontaneity Objectives Define entropy and examine its statistical nature Predict the sign of entropy changes for phase
Chapter 17.3 Entropy and Spontaneity Objectives Define entropy and examine its statistical nature Predict the sign of entropy changes for phase changes Apply the second law of thermodynamics to chemical
More informationCh 17 Free Energy and Thermodynamics - Spontaneity of Reaction
Ch 17 Free Energy and Thermodynamics - Spontaneity of Reaction Modified by Dr. Cheng-Yu Lai spontaneous nonspontaneous Spontaneous Processes Processes that are spontaneous in one direction are nonspontaneous
More informationChapter 16. Thermodynamics. Thermochemistry Review. Calculating H o rxn. Predicting sign for H o rxn. Creative Commons License
Chapter 16 Thermodynamics GCC CHM152 Creative Commons License Images and tables in this file have been used from the following sources: OpenStax: Creative Commons Attribution License 4.0. ChemWiki (CC
More informationCHM 112 Chapter 16 Thermodynamics Study Guide
CHM 112 Chapter 16 Thermodynamics Study Guide Remember from Chapter 5: Thermodynamics deals with energy relationships in chemical reactions Know the definitions of system, surroundings, exothermic process,
More informationThermodynamics. Chem 36 Spring The study of energy changes which accompany physical and chemical processes
Thermodynamics Chem 36 Spring 2002 Thermodynamics The study of energy changes which accompany physical and chemical processes Why do we care? -will a reaction proceed spontaneously? -if so, to what extent?
More informationChapter 17. Free Energy and Thermodynamics. Chapter 17 Lecture Lecture Presentation. Sherril Soman Grand Valley State University
Chapter 17 Lecture Lecture Presentation Chapter 17 Free Energy and Thermodynamics Sherril Soman Grand Valley State University First Law of Thermodynamics You can t win! The first law of thermodynamics
More informationChapter Eighteen. Thermodynamics
Chapter Eighteen Thermodynamics 1 Thermodynamics Study of energy changes during observed processes Purpose: To predict spontaneity of a process Spontaneity: Will process go without assistance? Depends
More informationIn previous chapters we have studied: Why does a change occur in the first place? Methane burns but not the reverse CH 4 + 2O 2 CO 2 + 2H 2 O
Chapter 19. Spontaneous Change: Entropy and Free Energy In previous chapters we have studied: How fast does the change occur How is rate affected by concentration and temperature How much product will
More informationUnit 5: Spontaneity of Reaction. You need to bring your textbooks everyday of this unit.
Unit 5: Spontaneity of Reaction You need to bring your textbooks everyday of this unit. THE LAWS OF THERMODYNAMICS 1 st Law of Thermodynamics Energy is conserved ΔE = q + w 2 nd Law of Thermodynamics A
More informationChapter 19. Entropy, Free Energy, and Equilibrium
Chapter 19 Entropy, Free Energy, and Equilibrium Spontaneous Physical and Chemical Processes A waterfall runs downhill A lump of sugar dissolves in a cup of coffee At 1 atm, water freezes below 0 0 C and
More information4/19/2016. Chapter 17 Free Energy and Thermodynamics. First Law of Thermodynamics. First Law of Thermodynamics. The Energy Tax.
Chemistry: A Molecular Approach, 2nd Ed. Nivaldo Tro First Law of Thermodynamics Chapter 17 Free Energy and Thermodynamics You can t win! First Law of Thermodynamics: Energy cannot be created or destroyed
More informationThermodynamics Spontaneity. 150/151 Thermochemistry Review. Spontaneity. Ch. 16: Thermodynamics 12/14/2017
Ch. 16: Thermodynamics Geysers are a dramatic display of thermodynamic principles in nature. As water inside the earth heats up, it rises to the surface through small channels. Pressure builds up until
More informationThermodynamic Fun. Quick Review System vs. Surroundings 6/17/2014. In thermochemistry, the universe is divided into two parts:
Thermodynamic Fun Quick Review System vs. Surroundings In thermochemistry, the universe is divided into two parts: The tem: The physical process or chemical reaction in which we are interested. We can
More informationWhat is a spontaneous reaction? One, that given the necessary activation energy, proceeds without continuous outside assistance
What is a spontaneous reaction? One, that given the necessary activation energy, proceeds without continuous outside assistance Why do some reactions occur spontaneously & others do not? Atoms react to
More informationCh 18 Free Energy and Thermodynamics:
P a g e 1 Ch 18 Free Energy and Thermodynamics: Homework: Read Ch 18, Work out sample/practice exercises in the sections as you read, Ch 18: 27, 31, 33, 41, 43, 47, 51, 55, 61, 63, 67, 71, 77, 87 Check
More informationEntropy, Free Energy, and Equilibrium
Entropy, Free Energy, and Equilibrium Chapter 17 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Spontaneous Physical and Chemical Processes A waterfall runs
More informationUNIT 15: THERMODYNAMICS
UNIT 15: THERMODYNAMICS ENTHALPY, DH ENTROPY, DS GIBBS FREE ENERGY, DG ENTHALPY, DH Energy Changes in Reactions Heat is the transfer of thermal energy between two bodies that are at different temperatures.
More informationChapter 19 Chemical Thermodynamics Entropy and free energy
Chapter 19 Chemical Thermodynamics Entropy and free energy Learning goals and key skills: Explain and apply the terms spontaneous process, reversible process, irreversible process, and isothermal process.
More informationFree-energy change ( G) and entropy change ( S)
Free-energy change ( G) and entropy change ( S) A SPONTANEOUS PROCESS (e.g. diffusion) will proceed on its own without any external influence. A problem with H A reaction that is exothermic will result
More informationAdvanced Chemistry Practice Problems
Thermodynamics: Review of Thermochemistry 1. Question: What is the sign of DH for an exothermic reaction? An endothermic reaction? Answer: ΔH is negative for an exothermic reaction and positive for an
More informationThermodynamics. Thermodynamics of Chemical Reactions. Enthalpy change
Thermodynamics 1 st law (Cons of Energy) Deals with changes in energy Energy in chemical systems Total energy of an isolated system is constant Total energy = Potential energy + kinetic energy E p mgh
More informationThermodynamics: Free Energy and Entropy. Suggested Reading: Chapter 19
Thermodynamics: Free Energy and Entropy Suggested Reading: Chapter 19 System and Surroundings System: An object or collection of objects being studied. Surroundings: Everything outside of the system. the
More informationThermodynamics II. Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Thermodynamics II Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Spontaneous Physical and Chemical Processes A waterfall runs downhill A lump of sugar dissolves
More informationFirst Law of Thermodynamics. Example of Spontaneous Rxns. Reversible and Irreversible 8/2/2016
First Law of Thermodynamics The first law of thermodynamics states that the energy of the universe is conserved. If one object loses energy, another has to gain that energy. The mathematical relationship
More informationEntropy and Free Energy
Page 1 Entropy and Free Energy How to predict if a reaction can occur at a reasonable rate? KINEICS Chapter 17 How to predict if a reaction can occur, given enough time? HERMODYNAMICS 1 Objectives Spontaneity
More informationEntropy, Free Energy and the Direction of Chemical Reactions
Thermodynamics: Entropy, Free Energy and the Direction of Chemical Reactions Dr.ssa Rossana Galassi 320 4381420 rossana.galassi@unicam.it 20-1 Thermodynamics: Entropy, Free Energy, and the Direction of
More informationDisorder and Entropy. Disorder and Entropy
Disorder and Entropy Suppose I have 10 particles that can be in one of two states either the blue state or the red state. How many different ways can we arrange those particles among the states? All particles
More informationChapter 17. Spontaneity, Entropy, and Free Energy
Chapter 17 Spontaneity, Entropy, and Free Energy Thermodynamics Thermodynamics is the study of the relationship between heat and other forms of energy in a chemical or physical process. Thermodynamics
More informationThermodynamics: Entropy, Free Energy, and Equilibrium
Chapter 16 Thermodynamics: Entropy, Free Energy, and Equilibrium spontaneous nonspontaneous In this chapter we will determine the direction of a chemical reaction and calculate equilibrium constant using
More informationChapter 19. Chemical Thermodynamics. Chemical Thermodynamics
Chapter 19 Enthalpy A thermodynamic quantity that equal to the internal energy of a system plus the product of its volume and pressure exerted on it by its surroundings; Enthalpy is the amount of energy
More informationTHERMODYNAMICS. Dr. Sapna Gupta
THERMODYNAMICS Dr. Sapna Gupta FIRST LAW OF THERMODYNAMICS Thermodynamics is the study of heat and other forms of energy involved in chemical or physical processes. First Law of Thermodynamics Energy cannot
More informationChemical Thermodynamics
Page III-16-1 / Chapter Sixteen Lecture Notes Chemical Thermodynamics Thermodynamics and Kinetics Chapter 16 Chemistry 223 Professor Michael Russell How to predict if a reaction can occur, given enough
More informationENTROPY HEAT HEAT FLOW. Enthalpy 3/24/16. Chemical Thermodynamics. Thermodynamics vs. Kinetics
Chemical Thermodynamics The chemistry that deals with energy exchange, entropy, and the spontaneity of a chemical process. HEAT The energy that flows into or out of system because of a difference in temperature
More informationSaturday Study Session 1 3 rd Class Student Handout Thermochemistry
Saturday Study Session 1 3 rd Class Student Handout Thermochemistry Multiple Choice Identify the choice that best completes the statement or answers the question. 1. C 2 H 4 (g) + 3 O 2 (g) 2 CO 2 (g)
More information2/18/2013. Spontaneity, Entropy & Free Energy Chapter 16. The Dependence of Free Energy on Pressure Sample Exercises
Spontaneity, Entropy & Free Energy Chapter 16 16.7 The Dependence of Free Energy on Pressure Why is free energy dependent on pressure? Isn t H, enthalpy independent of pressure at constant pressure? No
More informationTHERMODYNAMICS I. TERMS AND DEFINITIONS A. Review of Definitions 1. Thermodynamics = Study of the exchange of heat, energy and work between a system
THERMODYNAMICS I. TERMS AND DEFINITIONS A. Review of Definitions 1. Thermodynamics = Study of the exchange of heat, energy and work between a system and its surroundings. a. System = That part of universe
More informationChpt 19: Chemical. Thermodynamics. Thermodynamics
CEM 152 1 Reaction Spontaneity Can we learn anything about the probability of a reaction occurring based on reaction enthaplies? in general, a large, negative reaction enthalpy is indicative of a spontaneous
More informationChapter 17: Energy and Kinetics
Pages 510-547 S K K Chapter 17: Energy and Kinetics Thermochemistry: Causes of change in systems Kinetics: Rate of reaction progress (speed) Heat, Energy, and Temperature changes S J J Heat vs Temperature
More informationCHEMICAL THERMODYNAMICS. Nature of Energy. ΔE = q + w. w = PΔV
CHEMICAL HERMODYNAMICS Nature of Energy hermodynamics hermochemistry Energy (E) Work (w) Heat (q) Some Definitions Study the transformation of energy from one form to another during physical and chemical
More informationChapter 19 Chemical Thermodynamics
Chapter 19 Chemical Thermodynamics Spontaneous Processes Entropy and the Second Law of Thermodynamics The Molecular Interpretation of Entropy Entropy Changes in Chemical Reactions Gibbs Free Energy Free
More informationSpontaneous Change.! Although exothermic processes tend to be spontaneous, spontaneous reactions can be exothermic or endothermic:
Spontaneous Change! Any process, once initiated, that continues without further intervention is spontaneous.! Although exothermic processes tend to be spontaneous, spontaneous reactions can be exothermic
More informationLecture #13. Chapter 17 Enthalpy and Entropy
Lecture #13 Chapter 17 Enthalpy and Entropy First Law of Thermodynamics Energy cannot be created or destroyed The total energy of the universe cannot change Energy can be transferred from one place to
More informationWhat s free about Gibbs free energy?
What s free about Gibbs free energy? The change in free energy for a process equals the maximum work that can be done by the system on the surroundings in a spontaneous process occurring at constant temperature
More informationChapter 17: Spontaneity, Entropy, and Free Energy
Chapter 17: Spontaneity, Entropy, and Free Energy Review of Chemical Thermodynamics System: the matter of interest Surroundings: everything in the universe which is not part of the system Closed System:
More informationThermodynamics- Chapter 19 Schedule and Notes
Thermodynamics- Chapter 19 Schedule and Notes Date Topics Video cast DUE Assignment during class time One Review of thermodynamics ONE and TWO Review of thermo Wksheet Two 19.1-4; state function THREE
More informationChapter 17 Spontaneity, Entropy, and Free Energy
Chapter 17 Spontaneity, Entropy, and Free Energy Thermodynamics The study of energy and its transformations 1 st Law of Thermodynamics The total energy of the Universe is constant Energy can therefore
More informationconcentrations (molarity) rate constant, (k), depends on size, speed, kind of molecule, temperature, etc.
#80 Notes Ch. 12, 13, 16, 17 Rates, Equilibriums, Energies Ch. 12 I. Reaction Rates NO 2(g) + CO (g) NO (g) + CO 2(g) Rate is defined in terms of the rate of disappearance of one of the reactants, but
More informationReaction Rates & Equilibrium. What determines how fast a reaction takes place? What determines the extent of a reaction?
Reaction Rates & Equilibrium What determines how fast a reaction takes place? What determines the extent of a reaction? Reactants Products 1 Reaction Rates Vary TNT exploding. A car rusting. Dead plants
More informationContents and Concepts
Contents and Concepts 1. First Law of Thermodynamics Spontaneous Processes and Entropy A spontaneous process is one that occurs by itself. As we will see, the entropy of the system increases in a spontaneous
More informationCh 10 Practice Problems
Ch 10 Practice Problems 1. Which of the following result(s) in an increase in the entropy of the system? I. (See diagram.) II. Br 2(g) Br 2(l) III. NaBr(s) Na + (aq) + Br (aq) IV. O 2(298 K) O 2(373 K)
More informationChapter 17 Spontaneity, Entropy, and Free Energy
Chapter 17 Spontaneity, Entropy, and Free Energy Thermodynamics The study of energy and its transformations 1 st Law of Thermodynamics The total energy of the Universe is constant Energy can therefore
More informationLecture 2. Review of Basic Concepts
Lecture 2 Review of Basic Concepts Thermochemistry Enthalpy H heat content H Changes with all physical and chemical changes H Standard enthalpy (25 C, 1 atm) (H=O for all elements in their standard forms
More informationUNIT 9 IB MATERIAL KINETICS & THERMODYNAMICS
UNIT 9 IB MATERIAL KINETICS & THERMODYNAMICS Name: ESSENTIALS: Know, Understand, and Be Able To State that combustion and neutralization are exothermic processes. Calculate the heat energy change when
More informationEnergy is the capacity to do work
1 of 10 After completing this chapter, you should, at a minimum, be able to do the following. This information can be found in my lecture notes for this and other chapters and also in your text. Correctly
More informationGeneral Chemistry I Concepts
Thermodynamics Thermodynamics The Three Laws of Thermodynamics (18.1) Spontaneous Processes (18.2) Entropy (18.3) The Second Law of Thermodynamics (18.4) Gibbs Free Energy (18.5) Free Energy and Chemical
More informationSecond Law of Thermodynamics
Second Law of Thermodynamics First Law: the total energy of the universe is a constant Second Law: The entropy of the universe increases in a spontaneous process, and remains unchanged in a process at
More informationChapter 19 Chemical Thermodynamics
Chapter 19. Chemical Thermodynamics Sample Exercise 19.2 (p. 819) Elemental mercury is a silver liquid at room temperature. Its normal freezing point is -38.9 o C, and its molar enthalpy of fusion is H
More informationThermochemistry Lecture
Thermochemistry Lecture Jennifer Fang 1. Enthalpy 2. Entropy 3. Gibbs Free Energy 4. q 5. Hess Law 6. Laws of Thermodynamics ENTHALPY total energy in all its forms; made up of the kinetic energy of the
More informationEnergy Ability to produce change or do work. First Law of Thermodynamics. Heat (q) Quantity of thermal energy
THERMOCHEMISTRY Thermodynamics Study of energy and its interconversions Energy is TRANSFORMED in a chemical reaction (POTENTIAL to KINETIC) HEAT (energy transfer) is also usually produced or absorbed -SYSTEM:
More informationThermodynamics is the study of the relationship between heat and other forms of energy that are involved in a chemical reaction.
Ch 18 Thermodynamics and Equilibrium Thermodynamics is the study of the relationship between heat and other forms of energy that are involved in a chemical reaction. Internal Energy (U) Internal energy
More informationThermodynamics Cont. Subtitle
Thermodynamics Cont. Subtitle System vs. Surroundings The system- the reactants and products of a reaction The surroundings- everything that surrounds a reaction Thermochemistry is concerned with the flow
More information5.2 Energy. N Goalby chemrevise.org Lattice Enthalpy. Definitions of enthalpy changes
5.2 Energy 5.2.1 Lattice Enthalpy Definitions of enthalpy changes Enthalpy change of formation The standard enthalpy change of formation of a compound is the energy transferred when 1 mole of the compound
More informationChapter 19 Chemical Thermodynamics
Chapter 19 Chemical Thermodynamics Kinetics How fast a rxn. proceeds Equilibrium How far a rxn proceeds towards completion Thermodynamics Study of energy relationships & changes which occur during chemical
More informationContents and Concepts
Contents and Concepts 1. First Law of Thermodynamics Spontaneous Processes and Entropy A spontaneous process is one that occurs by itself. As we will see, the entropy of the system increases in a spontaneous
More informationContents and Concepts
Contents and Concepts 1. First Law of Thermodynamics Spontaneous Processes and Entropy A spontaneous process is one that occurs by itself. As we will see, the entropy of the system increases in a spontaneous
More informationSpontaneity, Entropy, and Free Energy
Spontaneity, Entropy, and Free Energy A ball rolls spontaneously down a hill but not up. Spontaneous Processes A reaction that will occur without outside intervention; product favored Most reactants are
More informationCHAPTER 12: Thermodynamics Why Chemical Reactions Happen
CHAPTER 12: Thermodynamics Why Chemical Reactions Happen Useful energy is being "degraded" in the form of unusable heat, light, etc. A tiny fraction of the sun's energy is used to produce complicated,
More informationCHAPTER 16 REVIEW. Reaction Energy. SHORT ANSWER Answer the following questions in the space provided.
CHAPTER 16 REVIEW Reaction Energy SECTION 1 SHORT ANSWER Answer the following questions in the space provided. 1. For elements in their standard state, the value of H 0 f is 0. 2. The formation and decomposition
More informationCHAPTER 11: Spontaneous Change and Equilibrium
CHAPTER 11: Spontaneous Change and Equilibrium Goal of chapter: Be able to predict which direction a reaction will go (cases where there is not necessarily an equilibrium) At high temperatures, ice always
More informationReaction Rates & Equilibrium. What determines how fast a reaction takes place? What determines the extent of a reaction?
Reaction Rates & Equilibrium What determines how fast a reaction takes place? What determines the extent of a reaction? Reactants Products 1 Reaction Rates Vary TNT exploding. A car rusting. Dead plants
More informationChem 1B Dr. White 1 Chapter 17: Thermodynamics. Review From Chem 1A (Chapter 6, section 1) A. The First Law of Thermodynamics
Chem 1B Dr. White 1 Chapter 17: Thermodynamics Review From Chem 1A (Chapter 6, section 1) A. The First Law of Thermodynamics 17.1 Spontaneous Processes and Entropy A. Spontaneous Change Chem 1B Dr. White
More informationChapter 16, Thermodynamics: Entropy, Free Energy, and Equilibrium
Chapter 16, Thermodynamics: Entropy, Free Energy, and Equilibrium We have another shift in our study of chemistry in this chapter. Now we want to learn why some reactions proceed almost completely to products
More informationUNIT 15 - Reaction Energy & Reaction Kinetics. I. Thermochemistry: study of heat in chemical reactions and phase changes
I. Thermochemistry: study of heat in chemical reactions and phase changes II. A. Heat equation (change in temperature): Q = m. C. p T 1. Q = heat (unit is Joules) 2. m = mass (unit is grams) 3. C p = specific
More informationI PUC CHEMISTRY CHAPTER - 06 Thermodynamics
I PUC CHEMISTRY CHAPTER - 06 Thermodynamics One mark questions 1. Define System. 2. Define surroundings. 3. What is an open system? Give one example. 4. What is closed system? Give one example. 5. What
More informationEnergy Ability to produce change or do work. First Law of Thermodynamics. Heat (q) Quantity of thermal energy
THERMOCHEMISTRY Thermodynamics Study of energy and its interconversions Energy is TRANSFORMED in a chemical reaction (POTENTIAL to KINETIC) HEAT (energy transfer) is also usually produced or absorbed -SYSTEM:
More informationEntropy. Spontaneity. Entropy. Entropy mol of N 2 at 1 atm or 1 mol of N 2 at atm. process a process that occurs without intervention
Entropy Spontaneity process a process that occurs without intervention can be fast or slow Entropy (s) the measure of molecular randomness or disorder Think of entropy as the amount of chaos Entropy Predict
More informationThermodynamics. 1. Which of the following processes causes an entropy decrease?
Thermodynamics 1. Which of the following processes causes an entropy decrease? A. boiling water to form steam B. dissolution of solid KCl in water C. mixing of two gases in one container D. beach erosion
More informationChapter 16. Spontaneity, Entropy and Free energy
Chapter 16 Spontaneity, Entropy and Free energy Contents Spontaneous Process and Entropy Entropy and the second law of thermodynamics The effect of temperature on spontaneity Free energy Entropy changes
More informationThermodynamics and Equilibrium. Chemical thermodynamics is concerned with energy relationships in chemical reactions.
1 of 7 Thermodynamics and Equilibrium Chemical thermodynamics is concerned with energy relationships in chemical reactions. In addition to enthalpy (H), we must consider the change in randomness or disorder
More informationStudy of energy changes that accompany physical and chemical changes.
Thermodynamics: Study of energy changes that accompany physical and chemical changes. First Law of Thermodynamics: Energy is niether created nor destroyed but simply converted from one form to another.
More information1.8 Thermodynamics. N Goalby chemrevise.org. Definitions of enthalpy changes
1.8 Thermodynamics Definitions of enthalpy changes Enthalpy change of formation The standard enthalpy change of formation of a compound is the energy transferred when 1 mole of the compound is formed from
More informationChemical thermodynamics the area of chemistry that deals with energy relationships
Chemistry: The Central Science Chapter 19: Chemical Thermodynamics Chemical thermodynamics the area of chemistry that deals with energy relationships 19.1: Spontaneous Processes First law of thermodynamics
More information12A Entropy. Entropy change ( S) N Goalby chemrevise.org 1. System and Surroundings
12A Entropy Entropy change ( S) A SPONTANEOUS PROCESS (e.g. diffusion) will proceed on its own without any external influence. A problem with H A reaction that is exothermic will result in products that
More informationChemical Thermodynamics. Chapter 18
Chemical Thermodynamics Chapter 18 Thermodynamics Spontaneous Processes Entropy and Second Law of Thermodynamics Entropy Changes Gibbs Free Energy Free Energy and Temperature Free Energy and Equilibrium
More informationChapter 19 Chemical Thermodynamics
Chapter 19 Chemical Thermodynamics Kinetics How fast a rxn. proceeds Equilibrium How far a rxn proceeds towards completion Thermodynamics Study of energy relationships & changes which occur during chemical
More informationEntropy and Enthalpy Guided Notes. a) Entropy. b) Enthalpy. c ) Spontaneous. d) Non-spontaneous
Entropy and Enthalpy Guided Notes 1) Define a) Entropy b) Enthalpy c ) Spontaneous d) Non-spontaneous 2) There is a natural tendency for reaction to move to the side with enthalpy Minimum enthalpy is the
More informationThermochemistry: the study of energy (in the from of heat) changes that accompany physical & chemical changes
Thermochemistry Thermochemistry: the study of energy (in the from of heat) changes that accompany physical & chemical changes heat flows from high to low (hot cool) endothermic reactions: absorb energy
More information1. III only 2. II, III. 3. II only. 4. I only 5. I, III. 6. I, II, III correct
Version 001 EXAM 8 PRACTICE PROBLEMS chemistry (78712) 1 This print-out should have 20 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001
More informationGummy Bear Demonstration:
Name: Unit 8: Chemical Kinetics Date: Regents Chemistry Aim: _ Do Now: a) Using your glossary, define chemical kinetics: b) Sort the phrases on the SmartBoard into the two columns below. Endothermic Rxns
More information3/30/2017. Section 17.1 Spontaneous Processes and Entropy Thermodynamics vs. Kinetics. Chapter 17. Spontaneity, Entropy, and Free Energy
Chapter 17 Spontaneity, Entropy, and Thermodynamics vs. Kinetics Domain of Kinetics Rate of a reaction depends on the pathway from reactants to products. Thermodynamics tells us whether a reaction is spontaneous
More informationAP Chemistry Chapter 16 Assignment. Part I Multiple Choice
Page 1 of 7 AP Chemistry Chapter 16 Assignment Part I Multiple Choice 1984 47. CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2 H 2 O(l) H = 889.1 kj H f H 2 O(l) = 285.8 kj mol 1 H f CO 2 (g) = 393.3 kj mol 1 What is
More informationThermodynamics: Directionality of Chemical Reactions
Thermodynamics: Directionality of Chemical Reactions Josian W. Gibbs 1839-1903. Pioneered concepts of chemical thermodynamics and free energy. Ludwig Boltzmann 1844-1906. Famous for his equation statistically
More informationThermodynamics. Or, will it happen?
Thermodynamics Or, will it happen? Questions to answer 1. What is thermodynamics all about? 2. What are spontaneous reactions? 3. What does enthalpy have to do with predicting spontaneity? 4. What is entropy?
More informationChemical Thermodynamics
Quiz A 42.8 ml solution of ammonia (NH 3 ) is titrated with a solution of 0.9713 M hydrochloric acid. The initial reading on the buret containing the HCl was 47.13 ml and the final reading when the endpoint
More informationChapter 19. Chemical Thermodynamics
Chemistry, The Central Science, 10th edition Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten Chapter 19 John D. Bookstaver St. Charles Community College St. Peters, MO 2006, Prentice Hall,
More informationGeneral Chemistry I. Dr. PHAN TẠI HUÂN Faculty of Food Science and Technology Nong Lam University. Module 4: Chemical Thermodynamics
General Chemistry I Dr. PHAN TẠI HUÂN Faculty of Food Science and Technology Nong Lam University Module 4: Chemical Thermodynamics Zeroth Law of Thermodynamics. First Law of Thermodynamics (state quantities:
More informationClass XI Chapter 6 Thermodynamics Question 6.1: Choose the correct answer. A thermodynamic state function is a quantity (i) used to determine heat changes (ii) whose value is independent of path (iii)
More informationGeneral Entropy Trends
General Entropy Trends The following generally show an in entropy: 1. Phase changes from solid to liquid, or liquid to gas or a solid to a gas. SOLID LIQUID GAS low entropy high entropy 2. Chemical reactions
More information