Chapter 13. Chemical Equilibrium

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Chapter 13. Chemical Equilibrium"

Transcription

1 Chapter 13 Chemical Equilibrium

2 Chapter 13 Preview Chemical Equilibrium The Equilibrium condition and constant Chemical equilibrium, reactions, constant expression Equilibrium involving Pressure Chemical expressions involving gases Heterogeneous Equilibria Application of equilibrium constant and its calculations for pressure and concentrations Le Châtellier s Principle Effect of a change of concentration, pressure, and temperature on the reaction equilibrium

3 Introduction Reactions that stop far short from completion and have concentrations of reactants and products remain constant with time has reached Chemical equilibrium. Equilibrium is a state in which there are no observable changes as time goes by. Chemical equilibrium is achieved when: reaction is carried out in a closed vessel the concentrations of the reactants and products remain constant Types of Equilibria: Physical equilibrium H O (l) Chemical equilibrium N O 4 (g) H O (g) NO (g)

4 13.1 Equilibrium conditions and constant N O 4 (g) NO (g) equilibrium equilibrium equilibrium Start with NO Start with N O 4 Start with NO & N O 4

5 13. The Equilibrium constant constant N O 4 (g) K = [NO ] [N O 4 ] aa + bb NO (g) = 4.63 x 10-3 cc + dd K = [C]c [D] d [A] a [B] b Law of Mass Action If K >> 1 Equilibrium Will Lie to the right Favor products K << 1 Lie to the left Favor reactants

6 Homogenous equilibrium applies to reactions in which all reacting species are in the same phase. CH 3 COOH (aq) + H O (l) CH 3 COO - (aq) + H 3 O + (aq) K c = [CH 3 COO - ][H 3 O + ] [CH 3 COOH][H O] [H O] = constant K c = [CH 3 COO- ][H 3 O + ] [CH 3 COOH] = K c [H O] General practice not to include units for the equilibrium constant.

7 Review Question 1 Consider the chemical system CO + Cl COCl ; K = L/mol. How do the equilibrium concentrations of the reactants compare to the equilibrium concentration of the product? 1) They are much smaller. ) They are much bigger. 3) They are about the same. 4) They have to be exactly equal. 5) You can t tell from the information given.

8 Review Question Determine the equilibrium constant for the system N O 4 NO at 5 C. The concentrations are shown here: [N O 4 ] = 9.43 X 10 M, [NO ] = 1.41 X 10 M a) b) 6.69 c) 474 d) 0.04 e)

9 13.3 The Equilibrium expression Involving Pressures K c = [NO ] [N O 4 ] N O 4 (g) NO (g) PV = nrt P = (n/v)rt P = CRT K p = P NO P N O 4 In most cases K c K p aa (g) + bb (g) cc (g) + dd (g) K p = K c (RT) n n = moles of gaseous products moles of gaseous reactants = (c + d) (a + b)

10 The equilibrium concentrations for the reaction between carbon monoxide and molecular chlorine to form COCl (g) at 74 0 C are [CO] = 0.01 M, [Cl ] = M, and [COCl ] = 0.14 M. Calculate the equilibrium constants K c and K p. CO (g) + Cl (g) COCl (g) K c = [COCl ] 0.14 = [CO][Cl ] 0.01 x = 0 K p = K c (RT) n n = 1 = -1 R = T = = 347 K K p = 0 x (0.081 x 347) -1 = 7.7 The equilibrium constant K p for the reaction NO (g) NO (g) + O (g) is 158 at 1000K. What is the equilibrium pressure of O if the P = atm and P NO NO = 0.70 atm? K p = P NO P O P NO P O P NO = K p P NO P O = 347 atm

11 13.4 Heterogeneous Equilibria Heterogenous equilibrium applies to reactions in which reactants and products are in different phases. K c = CaCO 3 (s) [CaO][CO ] [CaCO 3 ] CaO (s) + CO (g) [CaCO 3 ] = constant [CaO] = constant K c = [CO ] = K c x [CaCO 3 ] [CaO] K p = P CO The concentration of solids and pure liquids are not included in the expression for the equilibrium constant.

12 Consider the following equilibrium at 95 K: NH 4 HS (s) NH 3 (g) + H S (g) The partial pressure of each gas is 0.65 atm. Calculate K p and K c for the reaction? K p = P NH3 P H S = 0.65 x 0.65 = K p = K c (RT) n K c = K p (RT) - n n = 0 = T = 95 K K c = x (0.081 x 95) - = 1.0 x 10-4

13 General Relations Chemical Kinetics and Chemical Equilibrium k f A + B AB k r rate f = k f [A][B] rate r = k r [AB ] Equilibrium rate f = rate r k f [A][B] = k r [AB ] k f [AB ] = K k c = r [A][B] The equilibrium constant of reversible reaction is the reciprocal of the original equilibrium constant. N O 4 (g) NO (g) NO (g) N O 4 (g) K = [NO ] [N O 4 ] = 4.63 x 10-3 K = [N O 4 ] = 1 [NO ] K = 16

14 General Relations The equilibrium constant of the sum of two or more reactions is given by the product of the equilibrium constants of the individual reactions. A + B C + D C + D E + F A + B E + F K c K c K c K c = [C][D] [A][B] K c = [E][F] [C][D] K c = [E][F] [A][B] K c = K c x K c

15 Writing Equilibrium Constant Expressions The concentrations of the reacting species in the condensed phase are expressed in M. In the gaseous phase, the concentrations can be expressed in M or in atm. The concentrations of pure solids, pure liquids and solvents do not appear in the equilibrium constant expressions. The equilibrium constant is a dimensionless quantity. In quoting a value for the equilibrium constant, you must specify the balanced equation and the temperature. If a reaction can be expressed as a sum of two or more reactions, the equilibrium constant for the overall reaction is given by the product of the equilibrium constants of the individual reactions.

16 13.5 Application of the Equilibrium Constant For nonequilibrium conditions, the expression having the same form as K c or K p is called the reaction quotient, Q c or Q p aa + bb + gg + hh + Q c = [C]c [D] d [G] g [H] h The reaction quotient is useful for predicting the direction in which a net change must occur to establish equilibrium

17 13.5 Application of the Equilibrium Constant The reaction quotient (Q c ) is calculated by substituting the initial concentrations of the reactants and products into the equilibrium constant expression. IF Q c = K c the system is at equilibrium Q c < K c system proceeds from left to right to reach equilibrium Q c > K c system proceeds from right to left to reach equilibrium

18 Question The reaction quotient for a system is 7. x 10. If the equilibrium constant for the system is 36, what will happen as equilibrium is approached? a) There will be a net gain in product. b) There will be a net gain in reactant. c) There will be a net gain in both product and reactant. d) There will be no net gain in either product or reactant. e) The equilibrium constant will decrease until it equals the reaction quotient. ANS: b) SECTION: 13.5 LEVEL: medium

19 Calculating Equilibrium Concentrations and Pressure 1. Calculating Q will help in determining the direction of change (x) to establish the equilibrium. Express the equilibrium concentrations of all species in terms of the initial concentrations and a single unknown x, which represents the change in concentration. 3. Write the equilibrium constant expression in terms of the equilibrium concentrations. Knowing the value of the equilibrium constant, solve for x. 4. Having solved for x, calculate the equilibrium concentrations of all species.

20 At C the equilibrium constant (K c ) for the reaction Br (g) Br (g) is 1.1 x If the initial concentrations are [Br ] = M and [Br] = 0.01 M, calculate the concentrations of these species at equilibrium. [ Br ] Q = = =.3 10 > [ Br ] Q>K the system will shift to the left, using x as the change in concentration of Br - K c Br (g) Br (g) Initial (M) Change (M) Equilibrium (M) x -x x x [Br] K c = K [Br ] c = ( x) x = 1.1 x 10-3 Solve for x

21 ( x) K c = = 1.1 x x 4x x = x 4x x = 0 ax + bx + c =0 x = -b ± b 4ac a Initial (M) Change (M) Equilibrium (M) x = 8.74x10-3 Br (g) Br (g) x -x x x x =.98x10-3 At equilibrium, [Br] = x = -5.48x10-3 M or 6.05x10-3 M At equilibrium, [Br ] = x = M

22 13.7 Le Châtelier s Principle If an external stress is applied to a system at equilibrium, the system adjusts in such a way that the stress is partially offset as the system reaches a new equilibrium position. Changes in Concentration N (g) + 3H (g) Equilibrium shifts left to offset stress NH 3 (g) Add NH 3

23 13.7 Le Châtelier s Principle Changes in Concentration continued Remove Add Remove Add aa + bb cc + dd Change Increase concentration of product(s) Decrease concentration of product(s) Increase concentration of reactant(s) Decrease concentration of reactant(s) Shifts the Equilibrium left right right left

24 13.7 Le Châtelier s Principle Changes in Volume and Pressure A (g) + B (g) C (g) Change Increase pressure Decrease pressure Increase volume Decrease volume Shifts the Equilibrium Side with fewest moles of gas Side with most moles of gas Side with most moles of gas Side with fewest moles of gas

25 13.7 Le Châtelier s Principle Changes in Temperature Change Increase temperature Decrease temperature Exothermic Rx K decreases K increases Endothermic Rx K increases K decreases colder hotter

26 13.7 Le Châtelier s Principle Adding a Catalyst does not change K does not shift the position of an equilibrium system system will reach equilibrium sooner uncatalyzed catalyzed Catalyst lowers E a for both forward and reverse reactions. Catalyst does not change equilibrium constant or shift equilibrium.

27 13.7 Le Châtelier s Principle Change Shift Equilibrium Change Equilibrium Constant Concentration yes no Pressure yes no Volume yes no Temperature yes yes Catalyst no no

28 Chemistry In Action Life at High Altitudes and Hemoglobin Production Hb (aq) + O (aq) HbO (aq) K c = [HbO ] [Hb][O ]

29 Chemistry In Action: The Haber Process N (g) + 3H (g) NH 3 (g) H 0 = -9.6 kj/mol

30 QUESTION Consider the following equilibrium: 4NH 3 (g) + 50 (g) 4NO(g) + 6H O(g) What would happen to the system if oxygen were added? 1) More ammonia would be produced. ) More oxygen would be produced. 3) The equilibrium would shift to the right. 4) The equilibrium would shift to the left. 5) Nothing would happen.

31 QUESTION Consider the following system at equilibrium: N (g) + 3H (g) NH 3 (g) kj Which of the following changes will shift the equilibrium to the right? a. Increasing the temperature b. Decreasing the temperature c. Increasing the volume d. Decreasing the volume e. Removing some NH 3 f. Adding some NH 3 g. Removing some N h. Adding some N

32 Review Questions K The equilibrium constant of the following reaction is.18 x 106 H + Br HBr What are the equilibrium concentrations of all the species if the starting concentration of HBr was 0.67 M. (0.67 x) = = x c H + Br HBr Initial (M): Change (M): +x +x x Equilibrium (M): x x (0.67 x) x x = x = The equilibrium concentrations are: [H ] = [Br ] = M [HBr] = 0.67 ( ) = 0.67 M

33 Problem # 4 (or 44 Ed.6) Starting with 4.0 mole of NH3 in.0 L container. After dissociation as given below,.0 mole remains. What is the K for this reaction NH 3 (g) N (g) + 3 H (g) K = 3 3 [N] [H] (0.50)(1.5) K = = [NH3] (1.0) = 1.7 [NH Initial 4.0 mol/.0 L 0 0 Let x mol/l of NH 3 react to reach equilibrium Change -x +x +3x Equil..0 - x x 3x From the problem: [NH 3 ] e =.0 mol/.0 L = 1.0 M =.0 x, x = 0.50 M [N ] = x = 0.50 M; [H ] = 3x = 3(0.50 M) = 1.5 M [N ] [H 3 ] ] 3

34 Problem # 51 At 35 o C, K = 1.6 x 10-5 for the following reaction. Calculate the concentration of all the species, if 1.0 mol of NOCl and 1.0 mole of NO are mixed in 1.0 L flask. 1.6 NOCl(g) NO(g)+ Cl (g) Initial 1.0 M 1.0 M 0 x mol/l of NOCl reacts to reach equilibrium Change -x +x +x Equil x x x 5 10 = ( 1.0+ x) ( x) (1.0) ( x) = (1.0 x) (1.0) (assuming x << 1.0) x = ; Assumptions are great (x is % of 1.0). [Cl ] = M and [NOCl] = [NO] = 1.0 M

Chemical Equilibrium

Chemical Equilibrium Chemical Equilibrium Chapter 14 1 Equilibrium is a state in which there are no observable changes as time goes by. Chemical equilibrium is achieved when: the rates of the forward and reverse reactions

More information

Principles of Reactivity: Chemical Equilibria

Principles of Reactivity: Chemical Equilibria Principles of Reactivity: Chemical Equilibria This chapter addresses the principle of equilibrium equilibrium What can you do to reestablish equilibrium? non-equilibrium Whose principle supports this?

More information

Chemical Equilibrium

Chemical Equilibrium Chapter 13 Chemical Equilibrium Equilibrium Physical Equilibrium refers to the equilibrium between two or more states of matter (solid, liquid and gas) A great example of physical equilibrium is shown

More information

Chapter 14. CHEMICAL EQUILIBRIUM

Chapter 14. CHEMICAL EQUILIBRIUM Chapter 14. CHEMICAL EQUILIBRIUM 14.1 THE CONCEPT OF EQUILIBRIUM AND THE EQUILIBRIUM CONSTANT Many chemical reactions do not go to completion but instead attain a state of chemical equilibrium. Chemical

More information

Chemistry 4th Edition McMurry/Fay

Chemistry 4th Edition McMurry/Fay 13 Ch a pt e r Chemical Equilibrium Chemistry 4th Edition McMurry/Fay Dr. Paul Charlesworth Michigan Technological University The Equilibrium State 01 Chemical Equilibrium: A state achieved when the rates

More information

K c = [C]c [D] d [A] a [B] b. k f [NO 2 ] = k r [N 2 O 4 ] = K eq = The Concept of Equilibrium. Chapter 15 Chemical Equilibrium

K c = [C]c [D] d [A] a [B] b. k f [NO 2 ] = k r [N 2 O 4 ] = K eq = The Concept of Equilibrium. Chapter 15 Chemical Equilibrium Chapter 15 Chemical Equilibrium Learning goals and key skills: Understand what is meant by chemical equilibrium and how it relates to reaction rates Write the equilibrium-constant expression for any reaction

More information

CHAPTER 14 (MOORE) CHEMICAL EQUILIBRIUM

CHAPTER 14 (MOORE) CHEMICAL EQUILIBRIUM CHAPTER 14 (MOORE) CHEMICAL EQUILIBRIUM This chapter deals with chemical equilibrium, or how far chemical reactions proceed. Some reactions convert reactants to products with near 100% efficiency but others

More information

CHEMICAL EQUILIBRIUM

CHEMICAL EQUILIBRIUM Chemistry 10 Chapter 14 CHEMICAL EQUILIBRIUM Reactions that can go in both directions are called reversible reactions. These reactions seem to stop before they go to completion. When the rate of the forward

More information

A k 1. At equilibrium there is no net change in [A] or [B], namely d[a] dt

A k 1. At equilibrium there is no net change in [A] or [B], namely d[a] dt Chapter 15: Chemical Equilibrium Key topics: Equilibrium Constant Calculating Equilibrium Concentrations The Concept of Equilibrium Consider the reaction A k 1 k 1 B At equilibrium there is no net change

More information

Gas Phase Equilibrium

Gas Phase Equilibrium Gas Phase Equilibrium Chemical Equilibrium Equilibrium Constant K eq Equilibrium constant expression Relationship between K p and K c Heterogeneous Equilibria Meaning of K eq Calculations of K c Solving

More information

Chemical Equilibrium. Rate Forward Reaction = Rate Reverse Reaction. Chapter 14. Hill, Petrucci, McCreary & Perry 4 th. Ed.

Chemical Equilibrium. Rate Forward Reaction = Rate Reverse Reaction. Chapter 14. Hill, Petrucci, McCreary & Perry 4 th. Ed. Chapter 14 Chemical Equilibrium Hill, Petrucci, McCreary & Perry 4 th Ed. Chemical Equilibrium Many Reactions seem to STOP before all the reactants are used up. The Concentrations of Reactants and Products

More information

Chapter 15: Chemical Equilibrium: How Much Product Does a Reaction Really Make?

Chapter 15: Chemical Equilibrium: How Much Product Does a Reaction Really Make? Chapter 15: Chemical Equilibrium: How Much Product Does a Reaction Really Make? End-of-Chapter Problems: 15.1-15.10, 15.13-15.14, 15.17-15.99, 15.102-15.104 Example: Ice melting is a dynamic process: H

More information

Answers: Given: No. [COCl 2 ] = K c [CO][Cl 2 ], but there are many possible values for [CO]=[Cl 2 ]

Answers: Given: No. [COCl 2 ] = K c [CO][Cl 2 ], but there are many possible values for [CO]=[Cl 2 ] Chemical Equilibrium What are the concentrations of reactants and products at equilibrium? How do changes in pressure, volume, temperature, concentration and the use of catalysts affect the equilibrium

More information

Equilibrium Notes Ch 14:

Equilibrium Notes Ch 14: Equilibrium Notes Ch 14: Homework: E q u i l i b r i u m P a g e 1 Read Chapter 14 Work out sample/practice exercises in the sections, Bonus Chapter 14: 23, 27, 29, 31, 39, 41, 45, 51, 57, 63, 77, 83,

More information

Chemistry 212 EXAM 1 January 27, 2004

Chemistry 212 EXAM 1 January 27, 2004 1 Chemistry 212 EXAM 1 January 27, 2004 _100 (of 100) KEY Name Part 1: Multiple Choice. (1 point each, circle only one answer, 1. Consider the following rate law: Rate = k[a] n [B] m How are the exponents

More information

Chapter 13. Chemical Equilibrium

Chapter 13. Chemical Equilibrium Chapter 13 Chemical Equilibrium Section 13.1 The Equilibrium Condition Section 13.1 The Equilibrium Condition Section 13.1 The Equilibrium Condition Section 13.1 The Equilibrium Condition Section 13.1

More information

AP* Chemistry CHEMICAL EQUILIBRIA: GENERAL CONCEPTS

AP* Chemistry CHEMICAL EQUILIBRIA: GENERAL CONCEPTS AP* Chemistry CHEMICAL EQUILIBRIA: GENERAL CONCEPTS THE NATURE OF THE EQUILIBRIUM STATE: Equilibrium is the state where the rate of the forward reaction is equal to the rate of the reverse reaction. At

More information

CHEM 1332 CHAPTER 14

CHEM 1332 CHAPTER 14 CHEM 1332 CHAPTER 14 1. Which is a proper description of chemical equilibrium? The frequencies of reactant and of product collisions are identical. The concentrations of products and reactants are identical.

More information

Chapter 14 Chemical Equilibrium

Chapter 14 Chemical Equilibrium Chapter 14 Chemical Equilibrium Forward reaction H 2 (g) + I 2 (g) 2HI(g) Reverse reaction 2HI(g) H 2 (g) + I 2 (g) At equilibrium H 2 (g) + I 2 (g) 2HI(g) Chemical equilibrium is reached when reactants

More information

Equilibrium. Equilibrium 1. Examples of Different Equilibria. K p H 2 + N 2 NH 3 K a HC 2 H 3 O 2 H C 2 H 3 O 2 K sp SrCrO 4 Sr CrO 4

Equilibrium. Equilibrium 1. Examples of Different Equilibria. K p H 2 + N 2 NH 3 K a HC 2 H 3 O 2 H C 2 H 3 O 2 K sp SrCrO 4 Sr CrO 4 Equilibrium 1 Equilibrium Examples of Different Equilibria K p H 2 + N 2 NH 3 K a HC 2 H 3 O 2 H + - + C 2 H 3 O 2 K sp SrCrO 4 Sr 2+ 2- + CrO 4 Equilibrium deals with: What is the balance between products

More information

Chapter 15 Chemical Equilibrium

Chapter 15 Chemical Equilibrium Chapter 15 Chemical Equilibrium Chemical reactions can reach a state of dynamic equilibrium. Similar to the equilibrium states reached in evaporation of a liquid in a closed container or the dissolution

More information

Sample Exercise 15.1 Writing Equilibrium-Constant Expressions

Sample Exercise 15.1 Writing Equilibrium-Constant Expressions Sample Exercise 15.1 Writing Equilibrium-Constant Expressions Write the equilibrium expression for K c for the following reactions: Solution Analyze: We are given three equations and are asked to write

More information

Consider: N 2 (g) + 3H 2 (g) 2NH 3 (g) G = -32.90 kj/mol. conc. time

Consider: N 2 (g) + 3H 2 (g) 2NH 3 (g) G = -32.90 kj/mol. conc. time 5.111 Lecture Summary #19 CHEMICAL EQUILIBRIUM (Chapter 9 Section 9.0-9.9) Topics Nature of Chemical Equilibrium Meaning of K Relationship between Equilibrium Expressions External Effects on K 19.1 Chemical

More information

Chemical Equilibrium. Chemical Equilibrium

Chemical Equilibrium. Chemical Equilibrium Chemical Equilibrium When some types of chemical reactions occur in the gas or solution phases, these reaction attain chemical equilibrium, i.e., the reaction does not go to completion, but the reaction

More information

Chemical Equilibrium. Chapter 17: Keeping the chemical themes straight. Chapter 17 Homework Problems. N2O4 (g) 2NO2 (g)

Chemical Equilibrium. Chapter 17: Keeping the chemical themes straight. Chapter 17 Homework Problems. N2O4 (g) 2NO2 (g) Chapter 17: Chemical Equilibrium Equilibrium: The Extent of Chemical Reactions 17.1 The Dynamic Nature of the Equilibrium State 17. The Reaction Quotient and the Equilibrium Constant 17.3 Expressing Equilibria

More information

We will be looking at: A. Judging the extent of a reaction B. Predicting the direction of a reaction C. Calculating equilibrium concentrations

We will be looking at: A. Judging the extent of a reaction B. Predicting the direction of a reaction C. Calculating equilibrium concentrations 13.5 Using the Equilibrium Constant We will be looking at: A. Judging the extent of a reaction B. Predicting the direction of a reaction C. Calculating equilibrium concentrations A. Judging the extent

More information

Chapter 13 - Chemical Equilibrium

Chapter 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 information

Chemical Equilibrium - Chapter 14

Chemical Equilibrium - Chapter 14 Chemical Equilibrium - Chapter 14 1. Dynamic Equilibrium a A + b B c C + d D At Equilibrium: Reaction is proceeding in both directions at the same rate. There is no net change in concentrations of reactants

More information

Chemical Equilibrium-A Dynamic Equilibrium

Chemical Equilibrium-A Dynamic Equilibrium Chemical Equilibrium-A Dynamic Equilibrium Page 1 When compounds react, they eventually form a mixture of products and (unreacted) reactants, in a dynamic equilibrium Much like water in a U-shape tube,

More information

Equilibrium Practice Problems

Equilibrium Practice Problems Equilibrium Practice Problems 1. Write the equilibrium expression for each of the following reactions: N 2 (g) + 3 H 2 (g) 2 NH 3 (g) K = [NH 3 ] 2 [N 2 ] [H 2 ] 3 I 2 (s) + Cl 2 (g) 2 ICl (g) K = [ICl]

More information

Chapter 13 Chemical Equilibrium. Equilibrium is Dynamic. The Equilibrium Constant. Equilibrium and Catalysts. Characteristics of Chemical Equilibrium

Chapter 13 Chemical Equilibrium. Equilibrium is Dynamic. The Equilibrium Constant. Equilibrium and Catalysts. Characteristics of Chemical Equilibrium Characteristics of Chemical Equilibrium John W. Moore Conrad L. Stanitski Peter C. Jurs http://academic.cengage.com/chemistry/moore Chapter 13 Chemical Equilibrium Many reactions fail to go to completion.

More information

EQUILIBRIUM. Consider the reversible system initially consisting of reactants only.

EQUILIBRIUM. Consider the reversible system initially consisting of reactants only. EQUILIBRIUM When non reversible chemical reactions proceed to completion, the concentration of the reactants gradually decrease, until there is NO limiting reactant remaining. Most chemical reactions,

More information

Ch14 Chemical Equilibrium. Modified by Dr. Cheng-Yu Lai

Ch14 Chemical Equilibrium. Modified by Dr. Cheng-Yu Lai Ch14 Chemical Equilibrium Modified by Dr. Cheng-Yu Lai CHEMICAL EQUILIBRIUM Chemical Equilibrium: Chemical Equilibrium When the rate of the forward reaction equals the rate of the reverse reaction and

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. A.P. Chemistry Practice Test - Ch. 13: Equilibrium Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) At equilibrium,. A) the rates of the forward

More information

CHAPTER 17 EQUILIBRIUM: THE EXTENT OF CHEMICAL REACTIONS

CHAPTER 17 EQUILIBRIUM: THE EXTENT OF CHEMICAL REACTIONS CHATER 17 EQUILIBRIUM: THE EXTENT OF CHEMICAL REACTIONS 17.1 If the rate of the forward reaction exceeds the rate of reverse reaction, products are formed faster than they are consumed. The change in reaction

More information

IN CHAPTER 13, we examined how fast a chemical reaction occurs. In this chapter we. Chemical Equilibrium

IN CHAPTER 13, we examined how fast a chemical reaction occurs. In this chapter we. Chemical Equilibrium 14 Chemical Equilibrium Every system in chemical equilibrium, under the influence of a change of any one of the factors of equilibrium, undergoes a transformation... [that produces a change]... in the

More information

Name AP Chemistry / / Chapter 13 Collected AP Exam Free Response Questions 1980 2010 Answers

Name AP Chemistry / / Chapter 13 Collected AP Exam Free Response Questions 1980 2010 Answers Name AP Chemistry / / Chapter 13 Collected AP Exam Free Response Questions 1980 2010 Answers 1980 - #6 NH 4 Cl(s) NH 3 (g) + HCl(g) ΔH = +42.1 kilocalories Suppose the substances in the reaction above

More information

CHAPTER 14 CHEMICAL EQUILIBRIUM

CHAPTER 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 information

CH 223 Chapter Thirteen Concept Guide

CH 223 Chapter Thirteen Concept Guide CH 223 Chapter Thirteen Concept Guide 1. Writing Equilibrium Constant Expressions Write the equilibrium constant (K c ) expressions for each of the following reactions: (a) Cu(OH) 2 (s) (b) Cu(NH 3 ) 4

More information

Test Review # 9. Chemistry R: Form TR9.13A

Test 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 information

Chemical Equilibria & the Application of Le Châtelier s Principle to General Equilibria. Example of Equilibrium. !A(g) + "B(g)!

Chemical Equilibria & the Application of Le Châtelier s Principle to General Equilibria. Example of Equilibrium. !A(g) + B(g)! Chemical Equilibria & the Application of Le Châtelier s Principle to General Equilibria CHEM 102H T. Hughbanks Example of Equilibrium N 2 + 3H 2! 2 NH 3 Reactions can occur, in principle, in either direction.

More information

Equilibrium Lecture #1. Schweitzer

Equilibrium Lecture #1. Schweitzer Equilibrium Lecture #1 Schweitzer What is equilibrium? Remember Equilibrium process between to competing reactions. At equilibrium the forward process is equal to the reverse process. *** It appears that

More information

Chapter 20. Thermodynamics p. 811 842. Spontaneity. What have we learned about spontaneity during this course?

Chapter 20. Thermodynamics p. 811 842. Spontaneity. What have we learned about spontaneity during this course? Chapter 20 p. 811 842 Spontaneous process: Ex. Nonspontaneous process: Ex. Spontaneity What have we learned about spontaneity during this course? 1) Q vs. K? 2) So.. Spontaneous process occurs when a system

More information

CHEMICAL EQUILIBRIUM Chapter 13

CHEMICAL EQUILIBRIUM Chapter 13 Page 1 1 hemical Equilibrium EMIAL EQUILIBRIUM hapter 1 The state where the concentrations of all reactants and products remain constant with time. On the molecular level, there is frantic activity. Equilibrium

More information

CHEM 102 CLASS NOTES Prof. Upali Siriwardane, Chemistry Program, Louisiana Tech University, Ruston, LA 71272 CHAPTER 14, Chemical Equilibrium Chapter

CHEM 102 CLASS NOTES Prof. Upali Siriwardane, Chemistry Program, Louisiana Tech University, Ruston, LA 71272 CHAPTER 14, Chemical Equilibrium Chapter CHEM 10 CLASS NOTES Prof. Upali Siriwardane, Chemistry Program, Louisiana Tech University, Ruston, LA 717 CHAPTER 14, Chemical Equilibrium Chapter 14. Chemical Equilibrium 14.1 Characteristics of Chemical

More information

Guide to Chapter 13. Chemical Equilibrium

Guide 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 information

Chemical Equilibrium. Chapter 13

Chemical Equilibrium. Chapter 13 Chemical Equilibrium Chapter 13 Chemical Equilibrium When neither the products nor the reactant concentrations change any more with time. Chemical Equilibrium When the forward rate of reaction is equal

More information

Thermodynamics 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 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 information

CHEMICAL EQUILIBRIUM (ICE METHOD)

CHEMICAL 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 information

b. Calculate the value of the equilibrium constant at 127ºC for the reaction 2NH 3 (g) N 2 (g) + 3H 2 (g)

b. Calculate the value of the equilibrium constant at 127ºC for the reaction 2NH 3 (g) N 2 (g) + 3H 2 (g) 1. Write the equilibrium expression for the following reaction: 4NH 3 (g) + 7O 2 (g) 4NO 2 (g) + 6H 2 O(g) 2. The following equilibrium concentrations were observed for this reaction at 127ºC: N 2 (g)

More information

CHAPTER 17 EQUILIBRIUM: THE EXTENT OF CHEMICAL REACTIONS

CHAPTER 17 EQUILIBRIUM: THE EXTENT OF CHEMICAL REACTIONS CHATER 17 EQUILIBRIUM: THE EXTENT OF CHEMICAL REACTIONS END OF CHATER ROBLEMS 17.1 If the rate of the forward reaction exceeds the rate of reverse reaction, products are formed faster than they are consumed.

More information

Enthalpy, Entropy, and Free Energy Calculations

Enthalpy, Entropy, and Free Energy Calculations Adapted from PLTL The energies of our system will decay, the glory of the sun will be dimmed, and the earth, tideless and inert, will no longer tolerate the race which has for a moment disturbed its solitude.

More information

Name AP CHEM / / Collected AP Exam Essay Answers for Chapter 16

Name AP CHEM / / Collected AP Exam Essay Answers for Chapter 16 Name AP CHEM / / Collected AP Exam Essay Answers for Chapter 16 1980 - #7 (a) State the physical significance of entropy. Entropy (S) is a measure of randomness or disorder in a system. (b) From each of

More information

Equilibrium. Ron Robertson

Equilibrium. Ron Robertson Equilibrium Ron Robertson Basic Ideas A. Extent of Reaction Many reactions do not go to completion. Those that do not are reversible with a forward reaction and reverse reaction. To be really correct we

More information

Chapter 13 Chemical Kinetics

Chapter 13 Chemical Kinetics Chapter 13 Chemical Kinetics Student: 1. The units of "reaction rate" are A. L mol -1 s -1. B. L 2 mol -2 s -1. C. s -1. D. s -2. E. mol L -1 s -1. 2. For the reaction BrO 3 - + 5Br - + 6H + 3Br 2 + 3H

More information

EQUILIBRIUM. Academic Success Center

EQUILIBRIUM. Academic Success Center EQUILIBRIUM Academic Success Center Definition Equilibrium is a state where the concentrations of the reactants and products no longer change with time. This doesn t mean there is no movement between the

More information

SECTION 14 CHEMICAL EQUILIBRIUM

SECTION 14 CHEMICAL EQUILIBRIUM 1-1 SECTION 1 CHEMICAL EQUILIBRIUM Many chemical reactions do not go to completion. That is to say when the reactants are mixed and the chemical reaction proceeds it only goes to a certain extent, and

More information

Mr. Bracken. Multiple Choice Review: Thermochemistry

Mr. 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 information

CaCO 3 (s) CaO(s) + CO 2 (g)

CaCO 3 (s) CaO(s) + CO 2 (g) CaCO 3 (s) CaO(s) + CO 2 (g) When heated, calcium carbonate decomposes according to the equation above. In a study of the decomposition of calcium carbonate, a student added a 50.0 g sample of powdered

More information

Chemical Reactions: Energy, Rates and Equilibrium

Chemical Reactions: Energy, Rates and Equilibrium Chemical Reactions: Energy, Rates and Equilibrium Chapter 7 Heat Changes During Chemical Reactions Bond Dissociation Energy- The amount of energy that must be supplied to break a bond and separate the

More information

Standard Free Energies of Formation at 298 K. Average Bond Dissociation Energies at 298 K

Standard 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 information

Form A. CORRECT: As gases mix, the disorder or number of microstates with the same energy increases. As a result, entropy increases as well.

Form A. CORRECT: As gases mix, the disorder or number of microstates with the same energy increases. As a result, entropy increases as well. Chem 130 Name Exam 3, Ch 7, 19, and a little 14 November 11, 2011 100 Points Please follow the instructions for each section of the exam. Show your work on all mathematical problems. Provide answers with

More information

Solving Equilibrium Problems. AP Chemistry Ms. Grobsky

Solving Equilibrium Problems. AP Chemistry Ms. Grobsky Solving Equilibrium Problems AP Chemistry Ms. Grobsky Types of Equilibrium Problems A typical equilibrium problem involves finding the equilibrium concentrations (or pressures) of reactants and products

More information

2. Write a balanced chemical equation which corresponds to the following equilibrium constant expression. 1/2 3/ 2

2. Write a balanced chemical equation which corresponds to the following equilibrium constant expression. 1/2 3/ 2 Practice Problems for Chem. 1B Exam 1 F2011 These represent the concepts covered for exam 1. There may be some additional net ionic equations from chem. 1A. This is not the exact exam! Sections 16.1-16.3

More information

CHEMICAL THERMODYNAMICS

CHEMICAL THERMODYNAMICS CHEMICAL THERMODYNAMICS Spontaneous reactions Nonspontaneous reactions Enthalpy change (ΔH) Exothermic and endothermic reactions Entropy change (ΔS) Gibbs free energy change, (ΔG) Free energy of formation

More information

Chemistry B11 Chapter 4 Chemical reactions

Chemistry 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 information

Standard States. Standard Enthalpy of formation

Standard States. Standard Enthalpy of formation Standard States In any thermochemical equation, the states of all reactants and products must be specified; otherwise it becomes difficult for scientists to understand the experimental results of other

More information

Ch 3. Rate Laws and Stoichiometry

Ch 3. Rate Laws and Stoichiometry Ch 3. Rate Laws and Stoichiometry How do we obtain r A = f(x)? We do this in two steps 1. Rate Law Find the rate as a function of concentration, r A = k fn (C A, C B ). Stoichiometry Find the concentration

More information

rate = k [NO] 2 [H 2 ] CHEMICAL KINETICS Review Exam 3 1. How FAST {Speed like miles per hour and 2. By what MECHANISM Does a Reaction Take Place?

rate = k [NO] 2 [H 2 ] CHEMICAL KINETICS Review Exam 3 1. How FAST {Speed like miles per hour and 2. By what MECHANISM Does a Reaction Take Place? Review Chap 14: CHEMICAL KINETICS Review Exam Chapters 14 15 16 CHEMICAL KINETICS DEALS WITH 1. How FAST {Speed like miles per hour and. By what MECHANISM Does a Reaction Take Place? Given the following

More information

Equilibrium, Acids and Bases Unit Summary:

Equilibrium, Acids and Bases Unit Summary: Equilibrium, Acids and Bases Unit Summary: Prerequisite Skills and Knowledge Understand concepts of concentration, solubility, saturation point, pressure, density, viscosity, flow rate, and temperature

More information

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. 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 information

Worked solutions to student book questions Chapter 16 Controlling the yield of reactions

Worked solutions to student book questions Chapter 16 Controlling the yield of reactions E1. Write an equation to show the equilibrium that exists between NaI(s) and Na + (aq) and I (aq). AE1. NaI(s) Na + (aq) + I (aq) E. a Sketch a graph of the change in the radioactivity of the solution

More information

CHEM1612 2014-N-2 November 2014

CHEM1612 2014-N-2 November 2014 CHEM1612 2014-N-2 November 2014 Explain the following terms or concepts. Le Châtelier s principle 1 Used to predict the effect of a change in the conditions on a reaction at equilibrium, this principle

More information

Chemistry 106 Fall 2007 Exam 3 1. Which one of the following salts will form a neutral solution on dissolving in water?

Chemistry 106 Fall 2007 Exam 3 1. Which one of the following salts will form a neutral solution on dissolving in water? 1. Which one of the following salts will form a neutral solution on dissolving in water? A. NaCN B. NH 4 NO 3 C. NaCl D. KNO 2 E. FeCl 3 2. Which one of the following is a buffer solution? A. 0.10 M KCN

More information

AP Chemistry Unit 7- Homework Problems Equilibrium and K sp

AP Chemistry Unit 7- Homework Problems Equilibrium and K sp AP Chemistry Unit 7- Homework Problems Equilibrium and K sp Nature of the Equilibrium State 1. Draw on this graph where equilibrium has been reached. [X] equilibrium time 2. What are three qualities of

More information

Worksheet 4. (b) Compute the equilibrium constant corresponding to the equation you wrote.

Worksheet 4. (b) Compute the equilibrium constant corresponding to the equation you wrote. 1. At 298 K, F 3 SSF (g) decomposes partially to SF 2 (g). At equilibrium, the partial pressure of SF 2 (g) is 1.1 10-4 atm and the partial pressure of F 3 SSF is 0.0484 atm. (a) Write a balanced equilibrium

More information

Reaction Mechanism (continued) CHEMICAL KINETICS. Pt 2. Reaction Mechanisms. Often Used Terms. Reaction Mechanisms. The reaction

Reaction Mechanism (continued) CHEMICAL KINETICS. Pt 2. Reaction Mechanisms. Often Used Terms. Reaction Mechanisms. The reaction Reaction Mechanism (continued) CHEMICAL KINETICS Pt The reaction C H O + 5O 6CO + 4H O 3 4 3 has many steps in the reaction mechanism. Objectives! Be able to describe the collision and transition-state

More information

STOICHIOMETRY. - the study of the quantitative aspects of chemical

STOICHIOMETRY. - the study of the quantitative aspects of chemical STOICHIOMETRY - the study of the quantitative aspects of chemical GENERAL PLAN FOR STOICHIOMETRY Mass reactant Mass product Moles reactant Stoichiometric factor Moles product STOICHIOMETRY It rests on

More information

Chapter 6 An Overview of Organic Reactions

Chapter 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 information

Thermodynamics- Chapter 19 Schedule and Notes

Thermodynamics- Chapter 19 Schedule and Notes Thermodynamics- Chapter 19 Schedule and Notes Date Topics Video cast DUE Assignment during class time One Review of thermodynamics 1_thermo_review AND Review of thermo Wksheet 2.1ch19_intro Optional: 1sc_thermo

More information

Chapter 18 Homework Answers

Chapter 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 information

Chapter 14. Review Skills

Chapter 14. Review Skills Chapter 14 The Process of Chemical Reactions ave you ever considered becoming a chemical engineer? The men and women in this profession develop industrial processes for the large-scale production of the

More information

Enthalpy of Reaction and Calorimetry worksheet

Enthalpy 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 information

C2 Chemistry Calculations

C2 Chemistry Calculations C2 Chemistry Calculations You need to know how to carry out several calculations in Additional Science This booklet gives you a step by step guide to carrying out these equations and examples of each one.

More information

Reaction Quotient. Trial 1 A (g) + B (g) C (g) Trial 2 A (g) + B (g) C (g) Initial 1.000 M 1.000 M 1.000 M Initial 2.000 M 0.500 M 0.

Reaction Quotient. Trial 1 A (g) + B (g) C (g) Trial 2 A (g) + B (g) C (g) Initial 1.000 M 1.000 M 1.000 M Initial 2.000 M 0.500 M 0. Reaction Quotient How do you predict which direction a reaction will proceed to reach equilibrium? Why? When a reaction reaches equilibrium there must be some non-negligible amount of every species in

More information

System. System, Boundary and surroundings: Nature of heat and work: Sign convention of heat: Unit-7 Thermodynamics

System. System, Boundary and surroundings: Nature of heat and work: Sign convention of heat: Unit-7 Thermodynamics Unit-7 Thermodynamics Introduction: The term Thermo means heat and dynamics means flow or movement.. So thermodynamics is concerned with the flow of heat. The different forms of the energy are interconvertible

More information

Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions

Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions How do we balance chemical equations? How can we used balanced chemical equations to relate the quantities of substances consumed and produced

More information

1. 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? 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 information

Equilibria Involving Acids & Bases

Equilibria Involving Acids & Bases Week 9 Equilibria Involving Acids & Bases Acidic and basic solutions Self-ionisation of water Through reaction with itself: The concentration of water in aqueous solutions is virtually constant at about

More information

FE Review Chemistry. Heather J. Shipley Assistant Professor Civil and Environmental Engineering UTSA

FE Review Chemistry. Heather J. Shipley Assistant Professor Civil and Environmental Engineering UTSA FE Review Chemistry Heather J. Shipley Assistant Professor Civil and Environmental Engineering UTSA Basic Concepts Nucleus of atom Proton: positively charged particle, 1.00728 amu Neutron: neutral particle,

More information

White Station High School Name

White Station High School Name White Station High School Name Chapter 13 ʺKineticsʺ Section: A1, A2, A3 TRUE/FALSE. Write ʹTʹ if the statement is true and ʹFʹ if the statement is false. 1) The instantaneous rate of a reaction can be

More information

Bomb Calorimetry. Example 4. Energy and Enthalpy

Bomb 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 information

AP Practice Questions

AP Practice Questions 1) AP Practice Questions The tables above contain information for determining thermodynamic properties of the reaction below. C 2 H 5 Cl(g) + Cl 2 (g) C 2 H 4 Cl 2 (g) + HCl(g) (a) Calculate ΔH for

More information

CHAPTER 12 GASES AND THEIR BEHAVIOR

CHAPTER 12 GASES AND THEIR BEHAVIOR Chapter 12 Gases and Their Behavior Page 1 CHAPTER 12 GASES AND THEIR BEHAVIOR 12-1. Which of the following represents the largest gas pressure? (a) 1.0 atm (b) 1.0 mm Hg (c) 1.0 Pa (d) 1.0 KPa 12-2. Nitrogen

More information

Thermodynamics Review

Thermodynamics Review Thermodynamics Review 1. According to Reference Table I, the dissolving of NH 4Cl(s) in water is 1) exothermic and the heat of reaction is negative 2) exothermic and the heat of reaction is positive 3)

More information

CHM1 Review for Exam 9

CHM1 Review for Exam 9 Topics 1. Reaction Types a. Combustion b. Synthesis c. Decomposition d. Single replacement i. Metal activity series ii. Nonmetal activity series e. Double replacement i. Precipitates and solubility rules

More information

V. POLYPROTIC ACID IONIZATION. NOTICE: K a1 > K a2 > K a3 EQUILIBRIUM PART 2. A. Polyprotic acids are acids with two or more acidic hydrogens.

V. POLYPROTIC ACID IONIZATION. NOTICE: K a1 > K a2 > K a3 EQUILIBRIUM PART 2. A. Polyprotic acids are acids with two or more acidic hydrogens. EQUILIBRIUM PART 2 V. POLYPROTIC ACID IONIZATION A. Polyprotic acids are acids with two or more acidic hydrogens. monoprotic: HC 2 H 3 O 2, HCN, HNO 2, HNO 3 diprotic: H 2 SO 4, H 2 SO 3, H 2 S triprotic:

More information

The Relationships Between. Internal Energy, Heat, Enthalpy, and Calorimetry

The Relationships Between. Internal Energy, Heat, Enthalpy, and Calorimetry The Relationships Between Internal Energy, Heat, Enthalpy, and Calorimetry Recap of Last Class Last class, we began our discussion about energy changes that accompany chemical reactions Chapter 5 discusses:

More information

AP Chemistry 2004 Scoring Guidelines Form B

AP Chemistry 2004 Scoring Guidelines Form B AP Chemistry 2004 Scoring Guidelines Form B The materials included in these files are intended for noncommercial use by AP teachers for course and exam preparation; permission for any other use must be

More information

How many moles are in a breath of air whose volume is 2.32L at body temperature (37 C) and a pressure of 745 torr?

How many moles are in a breath of air whose volume is 2.32L at body temperature (37 C) and a pressure of 745 torr? Lecture 9 State of gas described by (n,p,v,t) n # moles P pressure V volume T (absolute) temperature (K) Sample Problem A balloon filled with helium has a volume of 1.60 L at 1.00 atm and 25oC. What will

More information