CHAPTER 18 (MOORE) THERMODYNAMICS: SPONTANEITY, ENTROPY, AND FREE ENERGY
|
|
- Raymond Moore
- 7 years ago
- Views:
Transcription
1 CHAPTER 18 (MOORE) THERMODYNAMICS: SPONTANEITY, ENTROPY, AND FREE ENERGY This chapter deals with the idea of spontaneity in chemical and physical processes. Spontaneous means that a particular process can take place without outside help. We will introduce two new thermodynamic variables: entropy and free energy. In this chapter, we look at entropy and how it combines with enthalpy changes to influence free energy changes the silver bullet for spontaneity. Recall that, in Chapter 6 (Section 6.9), you looked at heats of reaction, enthalpy changes (ΔH) and Hess s Law You should carefully review Hill, pp and to refresh yourself about heats of reaction and how to calculate enthalpy changes using Hess s Law. Thermodynamics tells us what processes are possible; Kinetics tells us whether the process is practical. Spontaneous and Nonspontaneous Changes Spontaneous processes (changes) occur in systems left to themselves; no action from outside the system is required to cause the change. Nonspontaneous processes cannot take place in systems left to themselves. If a given process (e.g. an explosion) is spontaneous, then the reverse process is not spontaneous, and vice versa. Example 18.1 Indicate whether each of the following processes is spontaneous or nonspontaneous. (a) The boiling of water at normal atmospheric pressure and 65 C. Nonspontaneous below 100 C at 1 atm!! (b) The melting of an ice cube. Spontaneous!! (at room temperature or at any temperature above 0 C) Spontaneous and Nonspontaneous Changes Familiarity with a large number of chemical reactions has convinced chemists that spontaneous chemical reactions occur only for exothermic processes, when systems lose heat energy and ΔH is negative. 2 H 2 (g) + O 2 (g) 2 H 2 O(g) ΔH = kj (spontaneous and exothermic!) In fact, this is true for most chemical reactions, but not for all chemical reactions. So how can we explain this apparent discrepancy?
2 Falling water (higher to lower potential energy) is a spontaneous process. As shown previously, H 2 and O 2 combine spontaneously to form water (exothermic) BUT liquid water vaporizes spontaneously at room temperature; an endothermic process. Conclusion: enthalpy alone is not a sufficient criterion for prediction of spontaneity. Entropy (S) and Entropy Change (ΔS) Entropy is a mathematical concept used to describe the distribution of energy within a system. Entropy is a measure of the relative order/disorder in a system. Two gases mix spontaneously when the valve is opened, even though there is no significant enthalpy change why? Concept of Entropy The total energy of the system remains unchanged in the mixing of the gases but the number of ways the energy can be distributed increases. Mixing two different but chemically similar liquids likes dissolve likes Benzene and toluene have similar intermolecular forces essentially no enthalpy change when mixed. But the entropy (translate as relative disorder) of the mixture is higher than the entropies of the two substances separated, so mixing is spontaneous The difference in entropy (S) between two states, S 1 and S 2, is the entropy change (ΔS). ΔS = S 2 S 1, where where S 2 > S 1 implies an increase in disorder. Increase in Entropy When Water Vaporizes (less disorder ) H 2 O(l) H 2 O(g) (more disorder ) S 2 > S 1 We know that vaporization is spontaneous! So, ΔS = + (the sign of ΔS is positive) Some Important Thermodynamic Principles Distribution of energy among different states, with an increase in entropy, correlates with more physical disorder at the microscopic level we use entropy as a kind of measure of relative order/disorder. Spontaneous processes: occur when systems achieve lower energy states (ΔH is negative) and when system energy is distributed among more states (ΔS is positive). ΔH and ΔS may work together or in opposition. The sign of each one may be either positive or negative. Spontaneity depends upon which factor wins. The more different configurations of atoms, ions and molecules that exist among energy levels in a particular state of a system, the larger the entropy. Entropy usually increases when: 1. Solids liquids 2. Solids/liquids gases 3. Solids/liquids dissolve in a solvent to form solutions 4. Chemical reaction increases number of gas molecules 5. Temperature of a substances increases
3 Example 18.2 Predict whether each of the following leads to an increase or decrease in the entropy of a system. If in doubt, explain why. (a) N 2 (g) + 3 H 2 (g) 2 NH 3 (g) (b) C 12 H 22 O 11 (s) C 12 H 22 O 11 (aq) (c) CO(NH 2 ) 2 (aq) CO(NH 2 ) 2 (s) decreases (fewer gas molecules on right than on left) increases (solid to liquid) decreases (aqueous to solid) Entropy Change (ΔS) Is a State Function ΔS = q rxn /T where q rxn is reversible heat Reversible processes may be reversed by very small changes, as in the expansion of this gas. Reversible processes are never very far from equilibrium. Entropy Increases with Temperature Entropy always increases with temperature entropy increases dramatically during phase changes. (s l g). Standard Molar Entropies By definition, the entropy of a pure, perfect crystal is zero at 0 K (Third Law of Thermodynamics) What happens as the temperature is increased? Entropy increases!! (ΔS is positive) standard molar entropy, S : the entropy of 1 mole of a compound or an element in its standard state (most stable form at 1 atm, 298 K) Since entropy increases with temperature, the signs of standard molar entropies are all positive. Calculation of ΔS Using Hess s Law ΔS = Σ S (products) Σ S (reactants) Example Use data from Appendix C to calculate the standard entropy change at 25 C for the process in which: 4 HCl(g) + O 2 (g) 2 Cl 2 (g) + 2 H 2 O(g) J/ mol K J/ mol K J/mol K J/mol K ΔS 0 = [2 mol(233.0 J/mol K +2 mol(188.7 J/mol K)] [4 mol(186.8 J/mol K)+1 mol(205.0 J/mol K)] ΔS 0 = J/K The Second Law of Thermodynamics All spontaneous processes increase the entropy of the universe (the system and its surroundings). Entropy can be used as a sole criterion for spontaneous change but the entropy change of both the system and its surroundings must be considered. ΔS(universe) = ΔS(system) + ΔS(surroundings but, for a spontaneous process, ΔS(universe) > 0 so, ΔS(surr) = q(surr)/t = ΔH(sys)/T thus: ΔS(univ) = ΔS(sys) ΔH(sys)/T
4 (ΔS(universe) = ΔS(system) + ΔS(surroundings) or, multiplying by T, TΔS(univ) = ΔH(sys) TΔS(sys) Now, let TΔS(univ) = ΔG, where ΔG is called the change in Gibbs free energy (G) Gibbs Free Energy and Free Energy Change *Thus, for any process at constant T and P: ΔG(sys) = ΔH(sys) T ΔS(sys), or ΔG = ΔH T ΔS If ΔG < 0 (negative), a process is spontaneous as written. If ΔG > 0 (positive), a process is nonspontaneous as written. If ΔG = 0, neither the forward nor the reverse process is favored; there is no net change, and the process is at equilibrium. ΔH, ΔS, ΔG and Spontaneous Change At high T, TΔS is large: TΔS > ΔH At low T, TΔS is small: ΔH > TΔS Free Energy (Gibbs Free Energy) Free energy is a thermodynamic function that relates enthalpy and entropy to spontaneity, and can also be related to equilibrium constants. ΔG represents the maximum work available from a system. Standard Free Energy Change, ΔG free energy change when reactants and products are in their standard states (most stable form, 1 atm, 298 K) standard free energy of formation, ΔG f free energy change for the formation of 1 mol of substance in its standard state from its elements in their standard states Calculation of ΔG 0 Using the Gibbs Equation Example 18.6 Calculate ΔG at 298 K for the reaction 4 HCl(g) + O 2 (g) 2 Cl 2 (g) + 2 H 2 O(g) ΔH = kj kj/mol (a) using the Gibbs equation, ΔG 0 = ΔH 0 T ΔS 0 Calculate ΔS 0 from S 0 values using Hess s Law: get S 0 values from Table C.1 (Appendix C) ΔS 0 = [2(223.0) + 2(188.7)] [4(186.8) + 1(205.0)] = J/K = kj/k
5 ΔG 0 = ΔH 0 T ΔS 0 = kj (298 K)( kj/k) = 76.0 kj Calculation of ΔG 0 Using Hess s Law: ΔG = Σ ΔG f (products) Σ ΔG f (reactants) Example 18.6 (see Appendix J, pp. A.38-A.44, for ΔG 0 values) Calculate ΔG at 298 K for the reaction, 4 HCl(g) + O 2 (g) 2 Cl 2 (g) + 2 H 2 O(g) (b) from standard free energies of formation (ΔG f 0 ), in kj/mol ΔG 0 = [2( 228.6) + 2(0)] [4( 95.30) + 1(0)] = 76.0 kj Free Energy Change and Equilibrium At equilibrium, ΔG = 0 and reaction is neither product-favored nor reactant favored. or, ΔG = 0 = ΔH TΔS at a temperature, T, where the process is at equilibrium Thus, at the equilibrium temperature, ΔH = TΔS and ΔS = ΔH / T ΔS vap = ΔH vap /T bp (Trouton s rule) or, T bp ΔH vap / ΔS vap Works best with nonpolar substances but not for liquids with lots of hydrogen bonding. Estimating Normal Boiling Point Trouton s Rule Example 18.7 At its normal boiling point, the enthalpy of vaporization of pentadecane, CH 3 (CH 2 ) 13 CH 3, is kj/mol. What should its approximate normal boiling point temperature be? T bp ΔH vap / ΔS vap = kj/mol / kj/mol K) 570 K ΔG and the Equilibrium Constant, K C When ΔG = 0, then ΔG = RT ln K C ln K C = ΔG 0 / (RT) Calculating Equilibrium Constants ln K C = ΔG 0 / (RT) (R = J/mol K) Example 18.9 Determine the value of K C at 25 C for the reaction (Hint: first convert ΔG 0 to J/mol) 2 NO 2 (g) N 2 O 4 (g) ΔG 0 = 4.78 kj = 4.78 x 10 3 J ln K C = ΔG 0 / (RT) = ( 4.78 x 103 J)/{( J/mol K)(298 K)} ln K C = 1.93 K C = exp(1.93) = 6.9 Sign and Magnitude of ΔG Large, negative ΔG ; equilibrium lies far to right. Large, positive ΔG ; equilibrium lies far to left. Intermediate ΔG ; KC 1??
6 Summary: Thermodynamics determines the equilibrium state of any system and can predict the relative proportions of products and reactants at equilibrium. Since kinetics determines the pathway by which equilibrium is reached, high activation energies can effectively block reactions that are thermodynamically favored.
The first law: transformation of energy into heat and work. Chemical reactions can be used to provide heat and for doing work.
The first law: transformation of energy into heat and work Chemical reactions can be used to provide heat and for doing work. Compare fuel value of different compounds. What drives these reactions to proceed
More informationStandard Free Energies of Formation at 298 K. Average Bond Dissociation Energies at 298 K
1 Thermodynamics There always seems to be at least one free response question that involves thermodynamics. These types of question also show up in the multiple choice questions. G, S, and H. Know what
More informationChapter 18 Homework Answers
Chapter 18 Homework Answers 18.22. 18.24. 18.26. a. Since G RT lnk, as long as the temperature remains constant, the value of G also remains constant. b. In this case, G G + RT lnq. Since the reaction
More informationBomb Calorimetry. Example 4. Energy and Enthalpy
Bomb Calorimetry constant volume often used for combustion reactions heat released by reaction is absorbed by calorimeter contents need heat capacity of calorimeter q cal = q rxn = q bomb + q water Example
More informationCHEM 36 General Chemistry EXAM #1 February 13, 2002
CHEM 36 General Chemistry EXAM #1 February 13, 2002 Name: Serkey, Anne INSTRUCTIONS: Read through the entire exam before you begin. Answer all of the questions. For questions involving calculations, show
More informationThermodynamics. Thermodynamics 1
Thermodynamics 1 Thermodynamics Some Important Topics First Law of Thermodynamics Internal Energy U ( or E) Enthalpy H Second Law of Thermodynamics Entropy S Third law of Thermodynamics Absolute Entropy
More information11 Thermodynamics and Thermochemistry
Copyright ç 1996 Richard Hochstim. All rights reserved. Terms of use.» 37 11 Thermodynamics and Thermochemistry Thermodynamics is the study of heat, and how heat can be interconverted into other energy
More informationThermochemistry. r2 d:\files\courses\1110-20\99heat&thermorans.doc. Ron Robertson
Thermochemistry r2 d:\files\courses\1110-20\99heat&thermorans.doc Ron Robertson I. What is Energy? A. Energy is a property of matter that allows work to be done B. Potential and Kinetic Potential energy
More informationThermodynamics Worksheet I also highly recommend Worksheets 13 and 14 in the Lab Manual
Thermodynamics Worksheet I also highly recommend Worksheets 13 and 14 in the Lab Manual 1. Predict the sign of entropy change in the following processes a) The process of carbonating water to make a soda
More informationTest Review # 9. Chemistry R: Form TR9.13A
Chemistry R: Form TR9.13A TEST 9 REVIEW Name Date Period Test Review # 9 Collision theory. In order for a reaction to occur, particles of the reactant must collide. Not all collisions cause reactions.
More information1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics
Chem 105 Fri 10-23-09 1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics 10/23/2009 1 Please PICK UP your graded EXAM in front.
More informationName Class Date. In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.
Assessment Chapter Test A Chapter: States of Matter In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. The kinetic-molecular
More informationThermodynamics and Equilibrium
Chapter 19 Thermodynamics and Equilibrium Concept Check 19.1 You have a sample of 1.0 mg of solid iodine at room temperature. Later, you notice that the iodine has sublimed (passed into the vapor state).
More informationUnit 19 Practice. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question.
Name: Class: Date: Unit 19 Practice Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The first law of thermodynamics can be given as. A) E = q + w B) =
More informationWhy? Intermolecular Forces. Intermolecular Forces. Chapter 12 IM Forces and Liquids. Covalent Bonding Forces for Comparison of Magnitude
1 Why? Chapter 1 Intermolecular Forces and Liquids Why is water usually a liquid and not a gas? Why does liquid water boil at such a high temperature for such a small molecule? Why does ice float on water?
More informationMr. Bracken. Multiple Choice Review: Thermochemistry
Mr. Bracken AP Chemistry Name Period Multiple Choice Review: Thermochemistry 1. If this has a negative value for a process, then the process occurs spontaneously. 2. This is a measure of how the disorder
More informationvap H = RT 1T 2 = 30.850 kj mol 1 100 kpa = 341 K
Thermodynamics: Examples for chapter 6. 1. The boiling point of hexane at 1 atm is 68.7 C. What is the boiling point at 1 bar? The vapor pressure of hexane at 49.6 C is 53.32 kpa. Assume that the vapor
More informationChemistry B11 Chapter 4 Chemical reactions
Chemistry B11 Chapter 4 Chemical reactions Chemical reactions are classified into five groups: A + B AB Synthesis reactions (Combination) H + O H O AB A + B Decomposition reactions (Analysis) NaCl Na +Cl
More informationThermochemical equations allow stoichiometric calculations.
CHEM 1105 THERMOCHEMISTRY 1. Change in Enthalpy ( H) Heat is evolved or absorbed in all chemical reactions. Exothermic reaction: heat evolved - heat flows from reaction mixture to surroundings; products
More informationReading: Moore chapter 18, sections 18.6-18.11 Questions for Review and Thought: 62, 69, 71, 73, 78, 83, 99, 102.
Thermodynamics 2: Gibbs Free Energy and Equilibrium Reading: Moore chapter 18, sections 18.6-18.11 Questions for Review and Thought: 62, 69, 71, 73, 78, 83, 99, 102. Key Concepts and skills: definitions
More informationEnergy and Chemical Reactions. Characterizing Energy:
Energy and Chemical Reactions Energy: Critical for virtually all aspects of chemistry Defined as: We focus on energy transfer. We observe energy changes in: Heat Transfer: How much energy can a material
More informationStates of Matter CHAPTER 10 REVIEW SECTION 1. Name Date Class. Answer the following questions in the space provided.
CHAPTER 10 REVIEW States of Matter SECTION 1 SHORT ANSWER Answer the following questions in the space provided. 1. Identify whether the descriptions below describe an ideal gas or a real gas. ideal gas
More informationPV (0.775 atm)(0.0854 L) n = = = 0.00264 mol RT -1-1
catalyst 2 5 g ¾¾¾¾ 2 4 g 2 g DH298 = rxn DS298 C H OH( ) C H ( ) + H O( ) 45.5 kj/mol ; = 126 J/(K mol ) ethanol ethene water rxn 1 atm 760 torr PV (0.775 atm)(0.0854 L) n = = = 0.00264 mol RT -1-1 (0.08206
More informationEXERCISES. 16. What is the ionic strength in a solution containing NaCl in c=0.14 mol/dm 3 concentration and Na 3 PO 4 in 0.21 mol/dm 3 concentration?
EXERISES 1. The standard enthalpy of reaction is 512 kj/mol and the standard entropy of reaction is 1.60 kj/(k mol) for the denaturalization of a certain protein. Determine the temperature range where
More informationFinal Exam CHM 3410, Dr. Mebel, Fall 2005
Final Exam CHM 3410, Dr. Mebel, Fall 2005 1. At -31.2 C, pure propane and n-butane have vapor pressures of 1200 and 200 Torr, respectively. (a) Calculate the mole fraction of propane in the liquid mixture
More informationSpring 2009. kj mol 125 0-229 -92. H f. H rxn = Σ H f (products) - Σ H f (reactants)
Spring 2009 2. The reaction of an elemental halogen with an alkane is a very common reaction. The reaction between chlorine and butane is provided below. (NOTE: Questions a d and f pertain to this reaction.)
More informationThermodynamics of Mixing
Thermodynamics of Mixing Dependence of Gibbs energy on mixture composition is G = n A µ A + n B µ B and at constant T and p, systems tend towards a lower Gibbs energy The simplest example of mixing: What
More informationChapter 6 Thermodynamics: The First Law
Key Concepts 6.1 Systems Chapter 6 Thermodynamics: The First Law Systems, States, and Energy (Sections 6.1 6.8) thermodynamics, statistical thermodynamics, system, surroundings, open system, closed system,
More informationFORMA is EXAM I, VERSION 1 (v1) Name
FORMA is EXAM I, VERSION 1 (v1) Name 1. DO NOT TURN THIS PAGE UNTIL DIRECTED TO DO SO. 2. These tests are machine graded; therefore, be sure to use a No. 1 or 2 pencil for marking the answer sheets. 3.
More informationRead the sections on Allotropy and Allotropes in your text (pages 464, 475, 871-2, 882-3) and answer the following:
Descriptive Chemistry Assignment 5 Thermodynamics and Allotropes Read the sections on Allotropy and Allotropes in your text (pages 464, 475, 871-2, 882-3) and answer the following: 1. Define the word allotrope
More informationAP CHEMISTRY 2007 SCORING GUIDELINES. Question 2
AP CHEMISTRY 2007 SCORING GUIDELINES Question 2 N 2 (g) + 3 F 2 (g) 2 NF 3 (g) ΔH 298 = 264 kj mol 1 ; ΔS 298 = 278 J K 1 mol 1 The following questions relate to the synthesis reaction represented by the
More information4. Using the data from Handout 5, what is the standard enthalpy of formation of BaO (s)? What does this mean?
HOMEWORK 3A 1. In each of the following pairs, tell which has the higher entropy. (a) One mole of liquid water or one mole of water vapor (b) One mole of dry ice or one mole of carbon dioxide at 1 atm
More informationThe value of a state function is independent of the history of the system.
1 THERMODYNAMICS - The study of energy in matter - Thermodynamics allows us to predict whether a chemical reaction occurs or not. - Thermodynamics tells us nothing about how fast a reaction occurs. - i.
More informationPart B 2. Allow a total of 15 credits for this part. The student must answer all questions in this part.
Part B 2 Allow a total of 15 credits for this part. The student must answer all questions in this part. 51 [1] Allow 1 credit for 3 Mg(s) N 2 (g) Mg 3 N 2 (s). Allow credit even if the coefficient 1 is
More informationChapter 13 - Chemical Equilibrium
Chapter 1 - Chemical Equilibrium Intro A. Chemical Equilibrium 1. The state where the concentrations of all reactants and products remain constant with time. All reactions carried out in a closed vessel
More informationTest 5 Review questions. 1. As ice cools from 273 K to 263 K, the average kinetic energy of its molecules will
Name: Thursday, December 13, 2007 Test 5 Review questions 1. As ice cools from 273 K to 263 K, the average kinetic energy of its molecules will 1. decrease 2. increase 3. remain the same 2. The graph below
More informationEnthalpy of Reaction and Calorimetry worksheet
Enthalpy of Reaction and Calorimetry worksheet 1. Calcium carbonate decomposes at high temperature to form carbon dioxide and calcium oxide, calculate the enthalpy of reaction. CaCO 3 CO 2 + CaO 2. Carbon
More informationChemical Bonds. Chemical Bonds. The Nature of Molecules. Energy and Metabolism < < Covalent bonds form when atoms share 2 or more valence electrons.
The Nature of Molecules Chapter 2 Energy and Metabolism Chapter 6 Chemical Bonds Molecules are groups of atoms held together in a stable association. Compounds are molecules containing more than one type
More informationProblem Set 3 Solutions
Chemistry 360 Dr Jean M Standard Problem Set 3 Solutions 1 (a) One mole of an ideal gas at 98 K is expanded reversibly and isothermally from 10 L to 10 L Determine the amount of work in Joules We start
More informationCHEMICAL EQUILIBRIUM (ICE METHOD)
CHEMICAL EQUILIBRIUM (ICE METHOD) Introduction Chemical equilibrium occurs when opposing reactions are proceeding at equal rates. The rate at which the products are formed from the reactants equals the
More informationDETERMINING THE ENTHALPY OF FORMATION OF CaCO 3
DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3 Standard Enthalpy Change Standard Enthalpy Change for a reaction, symbolized as H 0 298, is defined as The enthalpy change when the molar quantities of reactants
More informationGibbs Free Energy and Chemical Potential. NC State University
Chemistry 433 Lecture 14 Gibbs Free Energy and Chemical Potential NC State University The internal energy expressed in terms of its natural variables We can use the combination of the first and second
More informationChemistry 151 Final Exam
Chemistry 151 Final Exam Name: SSN: Exam Rules & Guidelines Show your work. No credit will be given for an answer unless your work is shown. Indicate your answer with a box or a circle. All paperwork must
More informationSUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS
SUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS Rearranging atoms. In a chemical reaction, bonds between atoms in one or more molecules (reactants) break and new bonds are formed with other atoms to
More informationIntroductory Chemistry, 3 rd Edition Nivaldo Tro. Roy Kennedy Massachusetts Bay Community College Wellesley Hills, Maqqwertd ygoijpk[l
Introductory Chemistry, 3 rd Edition Nivaldo Tro Quantities in Car an octane and oxygen molecules and carbon dioxide and water Chemical Reactions Roy Kennedy Massachusetts Bay Community College Wellesley
More informationwww.chemsheets.co.uk 17-Jul-12 Chemsheets A2 033 1
www.chemsheets.co.uk 17-Jul-12 Chemsheets A2 033 1 AS THERMODYNAMICS REVISION What is enthalpy? It is a measure of the heat content of a substance Enthalpy change ( H) = Change in heat content at constant
More informationUnit 5 Practice Test. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question.
Name: Class: Date: Unit 5 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The internal energy of a system is always increased by. A) adding
More informationUNIT 1 THERMOCHEMISTRY
UNIT 1 THERMOCHEMISTRY THERMOCHEMISTRY LEARNING OUTCOMES Students will be expected to: THERMOCHEMISTRY STSE analyse why scientific and technological activities take place in a variety individual and group
More informationENTROPY AND THE SECOND LAW OF THERMODYNAMICS
ENTROPY AND THE SECOND LAW OF THERMODYNAMICS Energy Reservoir The system consists of the red circles in the blue box. Energy and entropy fl ow out of the system. TIME Additional Energy is added to the
More informationCHEM 105 HOUR EXAM III 28-OCT-99. = -163 kj/mole determine H f 0 for Ni(CO) 4 (g) = -260 kj/mole determine H f 0 for Cr(CO) 6 (g)
CHEM 15 HOUR EXAM III 28-OCT-99 NAME (please print) 1. a. given: Ni (s) + 4 CO (g) = Ni(CO) 4 (g) H Rxn = -163 k/mole determine H f for Ni(CO) 4 (g) b. given: Cr (s) + 6 CO (g) = Cr(CO) 6 (g) H Rxn = -26
More informationThe First Law of Thermodynamics
Thermodynamics The First Law of Thermodynamics Thermodynamic Processes (isobaric, isochoric, isothermal, adiabatic) Reversible and Irreversible Processes Heat Engines Refrigerators and Heat Pumps The Carnot
More information5.111 Principles of Chemical Science
MIT OpenCourseWare http://ocw.mit.edu 5.111 Principles of Chemical Science Fall 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. Page 1 of 10 pages
More information48 Practice Problems for Ch. 17 - Chem 1C - Joseph
48 Practice Problems for Ch. 17 - Chem 1C - Joseph 1. Which of the following concentration measures will change in value as the temperature of a solution changes? A) mass percent B) mole fraction C) molality
More informationCHEMISTRY STANDARDS BASED RUBRIC ATOMIC STRUCTURE AND BONDING
CHEMISTRY STANDARDS BASED RUBRIC ATOMIC STRUCTURE AND BONDING Essential Standard: STUDENTS WILL UNDERSTAND THAT THE PROPERTIES OF MATTER AND THEIR INTERACTIONS ARE A CONSEQUENCE OF THE STRUCTURE OF MATTER,
More informationCHEM 120 Online Chapter 7
CHEM 120 Online Chapter 7 Date: 1. Which of the following statements is not a part of kinetic molecular theory? A) Matter is composed of particles that are in constant motion. B) Particle velocity increases
More informationCh 8.5 Solution Concentration Units % (m/m or w/w) = mass of solute x 100 total mass of solution mass of solution = mass solute + mass solvent
1 Ch 8.5 Solution Concentration Units % (m/m or w/w) = mass of solute x 100 total mass of solution mass of solution = mass solute + mass solvent % (v/v) = volume of solute x 100 volume of solution filled
More informationAP Chemistry 2005 Scoring Guidelines Form B
AP Chemistry 2005 Scoring Guidelines Form B The College Board: Connecting Students to College Success The College Board is a not-for-profit membership association whose mission is to connect students to
More informationCalorimetry: Heat of Vaporization
Calorimetry: Heat of Vaporization OBJECTIVES INTRODUCTION - Learn what is meant by the heat of vaporization of a liquid or solid. - Discuss the connection between heat of vaporization and intermolecular
More informationThermodynamics. Chapter 13 Phase Diagrams. NC State University
Thermodynamics Chapter 13 Phase Diagrams NC State University Pressure (atm) Definition of a phase diagram A phase diagram is a representation of the states of matter, solid, liquid, or gas as a function
More informationCHEMISTRY. Matter and Change. Section 13.1 Section 13.2 Section 13.3. The Gas Laws The Ideal Gas Law Gas Stoichiometry
CHEMISTRY Matter and Change 13 Table Of Contents Chapter 13: Gases Section 13.1 Section 13.2 Section 13.3 The Gas Laws The Ideal Gas Law Gas Stoichiometry State the relationships among pressure, temperature,
More informationa) Use the following equation from the lecture notes: = ( 8.314 J K 1 mol 1) ( ) 10 L
hermodynamics: Examples for chapter 4. 1. One mole of nitrogen gas is allowed to expand from 0.5 to 10 L reversible and isothermal process at 300 K. Calculate the change in molar entropy using a the ideal
More informationChapter 13: Electrochemistry. Electrochemistry. The study of the interchange of chemical and electrical energy.
Chapter 13: Electrochemistry Redox Reactions Galvanic Cells Cell Potentials Cell Potentials and Equilbrium Batteries Electrolysis Electrolysis and Stoichiometry Corrosion Prevention Electrochemistry The
More informationAAHS-CHEMISTRY FINAL EXAM PREP-REVIEW GUIDE MAY-JUNE 2014 DR. GRAY CLASS OF 2016
AAHS-CHEMISTRY FINAL EXAM PREP-REVIEW GUIDE MAY-JUNE 2014 DR. GRAY CLASS OF 2016 UNIT I: (CHAPTER 1-Zumdahl text) The Nature of Science and Chemistry 1. Explain why knowledge of chemistry is central to
More informationAP Chemistry 2009 Scoring Guidelines
AP Chemistry 2009 Scoring Guidelines The College Board The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded in 1900,
More informationChem 1721 Brief Notes: Chapter 19
Chem 1721 Brief Notes: Chapter 19 Chapter 19: Electrochemistry Consider the same redox reaction set up 2 different ways: Cu metal in a solution of AgNO 3 Cu Cu salt bridge electrically conducting wire
More information5. Which temperature is equal to +20 K? 1) 253ºC 2) 293ºC 3) 253 C 4) 293 C
1. The average kinetic energy of water molecules increases when 1) H 2 O(s) changes to H 2 O( ) at 0ºC 3) H 2 O( ) at 10ºC changes to H 2 O( ) at 20ºC 2) H 2 O( ) changes to H 2 O(s) at 0ºC 4) H 2 O( )
More informationAP CHEMISTRY 2009 SCORING GUIDELINES (Form B)
AP CHEMISTRY 2009 SCORING GUIDELINES (Form B) Question 3 (10 points) 2 H 2 O 2 (aq) 2 H 2 O(l) + O 2 (g) The mass of an aqueous solution of H 2 O 2 is 6.951 g. The H 2 O 2 in the solution decomposes completely
More informationReview - After School Matter Name: Review - After School Matter Tuesday, April 29, 2008
Name: Review - After School Matter Tuesday, April 29, 2008 1. Figure 1 The graph represents the relationship between temperature and time as heat was added uniformly to a substance starting at a solid
More informationCHAPTER 14 CHEMICAL EQUILIBRIUM
CHATER 14 CHEMICAL EQUILIBRIUM roblem Categories Biological: 14.98. Conceptual: 14.1, 14., 14.9, 14.5, 14.54, 14.55, 14.56, 14.57, 14.58, 14.59, 14.60, 14.61, 14.6, 14.66, 14.67, 14.68, 14.69, 14.81, 14.91,
More informationCHAPTER 14 THE CLAUSIUS-CLAPEYRON EQUATION
CHAPTER 4 THE CAUIU-CAPEYRON EQUATION Before starting this chapter, it would probably be a good idea to re-read ections 9. and 9.3 of Chapter 9. The Clausius-Clapeyron equation relates the latent heat
More informationChemistry 2014 Scoring Guidelines
AP Chemistry 2014 Scoring Guidelines 2014 The College Board. College Board, Advanced Placement Program, AP, AP Central, and the acorn logo are registered trademarks of the College Board. Visit the College
More informationChemistry 11 Some Study Materials for the Final Exam
Chemistry 11 Some Study Materials for the Final Exam Prefix Abbreviation Exponent giga G 10 9 mega M 10 6 kilo k 10 3 hecto h 10 2 deca da 10 1 deci d 10-1 centi c 10-2 milli m 10-3 micro µ 10-6 nano n
More informationExp 13 Volumetric Analysis: Acid-Base titration
Exp 13 Volumetric Analysis: Acid-Base titration Exp. 13 video (time: 47:17 minutes) Titration - is the measurement of the volume of a standard solution required to completely react with a measured volume
More informationCHEM 110: CHAPTER 3: STOICHIOMETRY: CALCULATIONS WITH CHEMICAL FORMULAS AND EQUATIONS
1 CHEM 110: CHAPTER 3: STOICHIOMETRY: CALCULATIONS WITH CHEMICAL FORMULAS AND EQUATIONS The Chemical Equation A chemical equation concisely shows the initial (reactants) and final (products) results of
More informationChapter 13. Properties of Solutions
Sample Exercise 13.1 (p. 534) By the process illustrated below, water vapor reacts with excess solid sodium sulfate to form the hydrated form of the salt. The chemical reaction is Na 2 SO 4(s) + 10 H 2
More informationYIELD YIELD REACTANTS PRODUCTS
Balancing Chemical Equations A Chemical Equation: is a representation of a chemical reaction in terms of chemical formulas Example: 1. Word Description of a Chemical Reaction When methane gas (CH 4 ) burns
More informationChapter 6 An Overview of Organic Reactions
John E. McMurry www.cengage.com/chemistry/mcmurry Chapter 6 An Overview of Organic Reactions Why this chapter? To understand organic and/or biochemistry, it is necessary to know: -What occurs -Why and
More information1. The Kinetic Theory of Matter states that all matter is composed of atoms and molecules that are in a constant state of constant random motion
Physical Science Period: Name: ANSWER KEY Date: Practice Test for Unit 3: Ch. 3, and some of 15 and 16: Kinetic Theory of Matter, States of matter, and and thermodynamics, and gas laws. 1. The Kinetic
More informationChapter 7 : Simple Mixtures
Chapter 7 : Simple Mixtures Using the concept of chemical potential to describe the physical properties of a mixture. Outline 1)Partial Molar Quantities 2)Thermodynamics of Mixing 3)Chemical Potentials
More information1. The graph below represents the potential energy changes that occur in a chemical reaction. Which letter represents the activated complex?
1. The graph below represents the potential energy changes that occur in a chemical reaction. Which letter represents the activated complex? 4. According to the potential energy diagram shown above, the
More informationChemistry 122 Mines, Spring 2014
Chemistry 122 Mines, Spring 2014 Answer Key, Problem Set 9 1. 18.44(c) (Also indicate the sign on each electrode, and show the flow of ions in the salt bridge.); 2. 18.46 (do this for all cells in 18.44
More informationChemical Kinetics. 2. Using the kinetics of a given reaction a possible reaction mechanism
1. Kinetics is the study of the rates of reaction. Chemical Kinetics 2. Using the kinetics of a given reaction a possible reaction mechanism 3. What is a reaction mechanism? Why is it important? A reaction
More informationCST Practice Test. Multiple Choice Questions
CST Practice Test Young NAME CST Practice Test Multiple Choice Questions 1) At 1 atm and 298 K, which of the K a values listed below represents the strongest acid? 5) Which electron-dot symbol represents
More informationThe Ideal Solution. ChemActivity T15
ChemActivity T15 The Ideal Solution Focus Question: An equi-molar mixture of benzene and toluene is prepared. What will be the composition of the vapor in equilibrium with this solution? Model 1: Benzene
More informationGuide to Chapter 13. Chemical Equilibrium
Guide to Chapter 13. Chemical Equilibrium We will spend five lecture days on this chapter. During the first class meeting we will focus on how kinetics makes a segue into equilibrium. We will learn how
More informationLecture 1: Physical Equilibria The Temperature Dependence of Vapor Pressure
Lecture 1: Physical Equilibria The Temperature Dependence of Vapor Pressure Our first foray into equilibria is to examine phenomena associated with two phases of matter achieving equilibrium in which the
More information10.7 Kinetic Molecular Theory. 10.7 Kinetic Molecular Theory. Kinetic Molecular Theory. Kinetic Molecular Theory. Kinetic Molecular Theory
Week lectures--tentative 0.7 Kinetic-Molecular Theory 40 Application to the Gas Laws 0.8 Molecular Effusion and Diffusion 43 Graham's Law of Effusion Diffusion and Mean Free Path 0.9 Real Gases: Deviations
More informationModule 5: Combustion Technology. Lecture 34: Calculation of calorific value of fuels
1 P age Module 5: Combustion Technology Lecture 34: Calculation of calorific value of fuels 2 P age Keywords : Gross calorific value, Net calorific value, enthalpy change, bomb calorimeter 5.3 Calculation
More informationEXPERIMENT 7 Reaction Stoichiometry and Percent Yield
EXPERIMENT 7 Reaction Stoichiometry and Percent Yield INTRODUCTION Stoichiometry calculations are about calculating the amounts of substances that react and form in a chemical reaction. The word stoichiometry
More informationAP Chemistry 2010 Scoring Guidelines Form B
AP Chemistry 2010 Scoring Guidelines Form B The College Board The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded
More informationINTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION. 37 74 20 40 60 80 m/e
CHM111(M)/Page 1 of 5 INTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION SECTION A Answer ALL EIGHT questions. (52 marks) 1. The following is the mass spectrum
More informationStudy the following diagrams of the States of Matter. Label the names of the Changes of State between the different states.
Describe the strength of attractive forces between particles. Describe the amount of space between particles. Can the particles in this state be compressed? Do the particles in this state have a definite
More informationChem 1A Exam 2 Review Problems
Chem 1A Exam 2 Review Problems 1. At 0.967 atm, the height of mercury in a barometer is 0.735 m. If the mercury were replaced with water, what height of water (in meters) would be supported at this pressure?
More informationCh 20 Electrochemistry: the study of the relationships between electricity and chemical reactions.
Ch 20 Electrochemistry: the study of the relationships between electricity and chemical reactions. In electrochemical reactions, electrons are transferred from one species to another. Learning goals and
More informationChapter 13 Properties of Solutions
Chemistry, The Central Science, 10th edition Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten Chapter 13 Properties of are homogeneous mixtures of two or more pure substances. In a solution,
More informationChapter 4 Practice Quiz
Chapter 4 Practice Quiz 1. Label each box with the appropriate state of matter. A) I: Gas II: Liquid III: Solid B) I: Liquid II: Solid III: Gas C) I: Solid II: Liquid III: Gas D) I: Gas II: Solid III:
More informationChapter 11 Properties of Solutions
Chapter 11 Properties of Solutions 11.1 Solution Composition A. Molarity moles solute 1. Molarity ( M ) = liters of solution B. Mass Percent mass of solute 1. Mass percent = 1 mass of solution C. Mole
More informationCHAPTER 6 Chemical Bonding
CHAPTER 6 Chemical Bonding SECTION 1 Introduction to Chemical Bonding OBJECTIVES 1. Define Chemical bond. 2. Explain why most atoms form chemical bonds. 3. Describe ionic and covalent bonding.. 4. Explain
More information