Hemijska ravnoteža se dostiže kada su: brzina direktne i povratne reakcije jednake i koncentracije reaktanata i proizvoda konstantne
|
|
- Sara Bryant
- 5 years ago
- Views:
Transcription
1 HEMIJSKA RAVNOTEŽA
2 Hemijska ravnoteža se dostiže kada su: brzina direktne i povratne reakcije jednake i koncentracije reaktanata i proizvoda konstantne Mehanička (stabilna, labilna, indiferentna) Statička Dinamička Hidrostatička Termodinamička RAVNOTEŽA Psihička Toplotna Fizičko-hemijska ravnoteža H 2 O(l) H 2 O(g) NaCl(s) Na + (aq) + Cl - (aq) Hemijska ravnoteža N 2 O 4 (g) 2NO 2 (g)
3 A+ B C + D DINAMIČKA RAVNOTEŽA!!! A+ B C + D C+ D A+ B [ 1 k1 A][ B] [ 2 k2 C][ D] 1[ A][ B] k dir k pov 2[ C][ D] dir pov Stanje ravnoteže ( dir = pov )
4 c k1[ A][ B] k2[ C][ D] K k k 1 2 [ C][ D] [ A][ B] Zakon o dejstvu masa, Guldberg & Waage, Proizvodi Reaktanti Stanje ravnoteže U toku hemijske reakcije, koncentracije reaktanata opadaju, a koncentracije proizvoda rastu. Posle nekog vremena od početka reakcije, nema MERLJIVE promene koncentracije reaktanata ili proizvoda. Takvo stanje jeste RAVNOTEŽNO STANJE SISTEMA - HEMIJSKA RAVNOTEŽA, a koncentracije su RAVNOTEŽNE KONCENTRACIJE. K C+ DA + B Ak2 [ ][ ] CDk [ ][ ] 1B1 1 K1 K 1 K
5 ZNAČAJ RAVNOTEŽE I MALO FILOZOFIJE NEMA REAKCIJE RAVNOTEŽNA REAKCIJA POTPUNA REAKCIJA 2H 2 (g) + O 2 (g) ( praskavi gas!) 2H 2 (g) + O 2 (g) 2H 2 O(g) Pt 2000 o C 2H 2 (g) + O 2 (g) 2H 2 O(g)
6 HEMIJSKA RAVNOTEŽA U HOMOGENIM SISTEMIMA: rastvori ili smeše gasova A A+ B B C C + D D CCv ABv DDAv K c -3 v B mol m za gasove v i g ili aq!!! v i -3 mol dm za rastvore K p Cp( Ap( ) ) CADp( Bp( ) ) D Pa i za gasove i = ( C + D ) - ( A + B ) s i lbpv = nrt p = crt p(a) = c(a)rt p(b) =... K K RT i p c i = 0 K p = K c Termodinamička konstanta ravnoteže: K θ a a θ θ (C) (A) C A a a θ θ (D) (B) D B [1]
7 K Značenje vrednosti K? N 2 (g) + 3H 2 (g) 2NH 3 (g) c 2 NH3 N H K >> K Ravnoteža je pomerena udesno! Favorizovana je direktna reakcija! 2 p (NH3 ) p(n ) p (H p ) K << 1 Ravnoteža je pomerena ulevo! Favorizovana je povratna reakcija! Proizvodi Reaktanti Reaktanti Proizvodi
8 HEMIJSKA RAVNOTEŽA U HETEROGENIM SISTEMIMA CaCO 3 (s) CaO(s) + CO 2 (g) Kc CO 2 K p p(co 2 ) ČVRSTE SUPSTANCE I TEČNOSTI U POSEBNOJ FAZI NE ULAZE U IZRAZ ZA KONSTANTU RAVNOTEŽE!!!
9 BaCl 2 2H 2 O(s) BaCl 2 (s) + 2H 2 O(g) K c H 2 2 O K 2 p p (H 2 O) Ag + (aq) + Cl - (aq) AgCl(s) K c [ Ag 1 ][ Cl ] C(s) + O 2 (g) CO 2 (g) K c p K CO2 [ O ] 2 p(co2) p(o ) 2 CH 3 COOH(aq) + H 2 O(l) CH 3 COO - (aq) + H 3 O + (aq) K c [ CH3COO ][ H3O [ CH COOH] 3 ] [H 2 O(l)] = const NE ULAZI U IZRAZ ZA K!!!
10 Složene reakcije 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] [A][B] K c = [E][F] [C][D] K c = K c K c Ako ravnotežna reakcija predstavlja zbir dve ili više reakcija, konstanta ravnoteže ukupne reakcije jednaka je proizvodu konstanti ravnoteža pojedinačnih reakcija.
11 Veza između konstante i termodinamike r G ө =-RT lnk ө r G ө < 0 lnk ө > 0 K ө > 1 r G ө = 0 lnk ө = 0 K ө = 1 r G ө > 0 lnk ө < 0 K ө < 1 r G r G ө < 0 proces je spontan r G ө = 0 sistem je u ravnoteži r G ө > 0 proces nije spontan ξ(r)- stepen reagovanja 100 % A + B 100 % C + D
12 LE ŠATELIJEOV PRINCIP (1895.) Ako se na sistem koji je u dinamičkoj ravnoteži izvrši spoljašnji uticaj promenom nekog od faktora ravnoteže (c, p, T,...), doći će do pomeranja ravnoteže u smeru suprostavljanja spoljašnjem uticaju. Muzički predlozi kako se suprostaviti spoljašnjim uticajima i vratiti u ravnotežu: Henri Le Châtelier "Stress, Shift, Change In Concentration" Haber-Bošov proces
13 Vrednost K zavisi od: - Reakcije (sistema) koju posmatramo (određuje je vrednost r G ө ) - Temperature na kojoj se reakcija odigrava. ZAVISNOST K OD TEMPERATURE K = f(t) K A - e r H θ / RT Promena K sa T proporcionalna je r H: d ln K dt r H RT r Hê > 0, T K ravnoteža se pomera u desnu stranu (favorizuje se direktna reakcija!!!) r Hê < 0, T K ( T K) ravnoteža se pomera u levu stranu (favorizuje se suprotna reakcija!!!) 2 θ
14 + E A+ B C + D -E -E A+ B C + D + E r H ө > 0 r H ө < 0 Dakle, zagrevanjem ili hlađenjem menjamo vrednost K i tako pomeramo položaj hemijske ravnoteže! Međutim, položaj hemijske ravnoteže može se pomeriti i na druge načine, ne menjajući vrednost K!
15 Promena temperature Le Šatelijeov princip Promena Povišenje temperature Sniženje temperature Egzotermna reakcija K se smanjuje K se povećava Endotermna reakcija K se povećava K se smanjuje 2NO 2 (g) N 2 O 4 (g) mrk bezbojan r H ө = -57 kj/mol r H ө < 0, T K vidimo mrku boju NO 2, ravnoteža se pomera u levu stranu (favorizuje se suprotna reakcija!!!)
16 UTICAJ PROMENE KONCENTRACIJE NA HEMIJSKU RAVNOTEŽU (T = const) A A+ B B C C + D D K c vc vd C D v A A v B B Važi pravilo: dodatkom komponente koja se nalazi na jednoj strani hemijske reakcije, ravnotežu pomeramo na suprotnu stranu. c(a) ili c(b) ravnoteža se pomera u desnu stranu (favorizuje se direktna reakcija!!!) c(c) ili c(d) ravnoteža se pomera u levu stranu (favorizuje se suprotna reakcija!!!) c(a) ili c(b) c(c) ili c(d)
17 Primer sa dodatkom reaktanata: H 2 (g) + I 2 (g) 2HI(g) r H ө = -51 kj mol -1 K = 710 (25 C) 64 (445 C) 46 (490 C)
18 Promena koncentracije Le Šatelijeov princip A A+ B B C C + D D Promena Povećanje koncentracije proizvoda Smanjenje koncentracije proizvoda Povećanje koncentracije reaktanata Smanjenje koncentracije reaktanata Pomeranje ravnoteže levo desno desno levo
19 UTICAJ PROMENE PRITISKA NA HEMIJSKU RAVNOTEŽU (T = const) A A(g) + B B(g) C C(g) + D D(g) K p Uticaj promene parcijalnih pritisaka? p(c) p(a) v v C A p(d) p(b) v v D B p i = c i RT Uticaj p i isti kao uticaj c i!!! p(a) ili p(b) ravnoteža se pomera u desnu stranu (favorizuje se direktna reakcija!!!) p(c) ili p(d) ravnoteža se pomera u levu stranu (favorizuje se suprotna reakcija!!!)
20 UTICAJ PROMENE PRITISKA NA HEMIJSKU RAVNOTEŽU (T = const) Uticaj ukupnog pritiska u sistemu? Porast ukupnog pritiska pomera ravnotežu u stranu gde nastaje manja količina gasova, tj. gde je manji zbir koeficijenata!!! (VAŽI ZA: i 0) N 2 (g) + 3H 2 (g) 2NH 3 (g) i = -2 p = 200 bar Za i = 0, promene ukupnog pritiska ne utiču na ravnotežu!!! H 2 (g) + I 2 (g) 2HI(g) i = 0 p nebitan!
21 Le Šatelijeov princip Promene ukupnog pritiska (i zapremine) pv = nrt, tj. p = nrt/v A(g) + B(g) C(g) Promena Povećanje pritiska Smanjenje pritiska Povećanje zapremine Smanjenje zapremine Pomeranje ravnoteže Na stranu gde je manja količina gasova Na stranu gde je veća količina gasova Na stranu gde je veća količina gasova Na stranu gde je manja količina gasova
22 UTICAJ KATALIZATORA E E Bez katalizatora Sa katalizatorom Katalizator smanjuje E a i za direktnu i za povratnu reakciju. Dodatak katalizatora: - ne menja K, - ne dovodi do promene položaja ravnoteže, - sistem brže dostiže stanje ravnoteže.
23 Le Šatelijeov princip REZIME Promena Pomeranje položaja ravnoteže Promena konstante ravnoteže, K Temperatura da da Koncentracija da ne Pritisak da ne Zapremina da ne Katalizator ne ne
24 Reakcija dobijanja sumpor-trioksida spada u ravnotežne reakcije: 2SO 2 (g) + O 2 (g) 2SO 3 (g) r H ө < 0. Objasniti kakav će uticaj na ravnotežnu količinu sumpor-trioksida imati sledeće promene: a) dodatak kiseonika, b) povećanje temperature, c) smanjenje zapremine reakcionog suda, d) sniženje parcijalnog pritiska kiseonika. (januar 2016.) Napisati izraze za konstante ravnoteže K c i K p reakcije prikazane hemijskom jednačinom: 3Fe(s) + 4H 2 O(g) Fe 3 O 4 (s) + 4H 2 (g) r H ө = 149,9 kj mol 1. Objasniti kako će sledeće promene uticati na položaj ravnoteže: a) dodatak gvožđa, b) povećanje pritiska u sudu, c) sniženje temperature, d) dodatak katalizatora. (septembar 2016.)
25 U sud zapremine 5,0 dm 3 uneto je po 0,25 mol metana i vode. Na 1000 ºC uspostavila se ravnoteža reakcije: CH 4 (g) + H 2 O(g) CO(g) + 3H 2 (g). Nakon uspostavljanja ravnoteže pritisak u sudu iznosio je 1,45 MPa. Izračunati formalnu konstantu ravnoteže K c ove reakcije na 1000 ºC. (septembar 2012.) Rešenje: 3,
26 Smeša joda i vodonika koja sadrži 25,5 mol. % joda, zagrejana je na 450 ºC do uspostavljanja ravnoteže reakcije: H 2 (g) + I 2 (g) 2HI(g). Formalna konstanta ravnoteže ove reakcije na 450 ºC je K p =49,25. Izračunati sastav smeše u mol. % posle uspostavljanja ravnoteže na temperaturi reakcije. (jun 2013.) Rešenje: x(h 2 )=50,0 mol. %, x(i 2 )=0,980 mol. %, x(hi)=49,0 mol. %.
Hemijska ravnoteža. Poglavlje 2.6 Zakon o dejstvu masa Van t Hofova reakciona izoterma Termodinamički uslov i položaj hemijske ravnoteže
Hemijska ravnoteža Poglavlje 2.6 Zakon o dejstvu masa Van t Hofova reakciona izoterma Termodinamički uslov i položaj hemijske ravnoteže Hemijska ravnoteža Odigravanje neke hemijske reakcije predstavlja
More informationThis is important to know that the P total is different from the initial pressure (1bar) because of the production of extra molecules!!! = 0.
Question 1: N O 4 (g) NO (g) Amounts of material at the initial state: n 0 0 Amounts of material at equilibrium: (1 α)n 0 αn 0 Where α equals 0.0488 at 300 K and α equals 0.141 at 400K. Step 1: Calculate
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 15 Equilibrium
Chapter 15. Chemical Equilibrium 15.1 The Concept of Equilibrium Chemical equilibrium is the point at which the concentrations of all species are constant. A dynamic equilibrium exists when the rates of
More informationBCIT Winter Chem Exam #1
BCIT Winter 2014 Chem 0012 Exam #1 Name: Attempt all questions in this exam. Read each question carefully and give a complete answer in the space provided. Part marks given for wrong answers with partially
More informationC h a p t e r 13. Chemical Equilibrium
C h a p t e r 13 Chemical Equilibrium Chemical equilibrium is achieved when: the rates of the forward and reverse reactions are equal and the concentrations of the reactants and products remain constant
More informationUnit 8: Equilibrium Unit Review
1. Predict the effect of increasing pressure on the position of equilibrium in the following systems: a. CH 4 (g) + 2H 2 O(g) CO 2 (g) + 4H 2 (g) b. N 2 O 5 (g) + NO(g) 3NO 2 (g) c. NO(g) + NO 2 (g) N
More informationThermohemija. Energija. Prvi zakon termodinamike. Entalpija / kalorimetrija
Thermohemija Energija Prvi zakon termodinamike Entalpija / kalorimetrija Hess-ov zakon Kirchoff-ov zakon Prenos toplote U endotermalnom procesu, toplota se uvek prenosi sa toplijeg objekta (okruženja)
More informationCHEMICAL EQUILIBRIUM Chapter 13
1 CHEMICAL EQUILIBRIUM Chapter 13 Pb 2+ (aq) + 2 Cl (aq) PbCl 2 (s) 1 Objectives Briefly review what we know of equilibrium Define the Equilibrium Constant (K eq ) and Reaction Quotient (Q) Determining
More informationCHAPTER 3: CHEMICAL EQUILIBRIUM
CHAPTER 3: CHEMICAL EQUILIBRIUM 1 LESSON OUTCOME Write & explain the concepts of chemical equilibrium Derive the equilibrium constant Kc or Kp Solving the problem using the ICE table 2 Equilibrium is a
More informationChemical Equilibrium. Professor Bice Martincigh. Equilibrium
Chemical Equilibrium by Professor Bice Martincigh Equilibrium involves reversible reactions Some reactions appear to go only in one direction are said to go to completion. indicated by All reactions are
More informationThe Equilibrium Law. Calculating Equilibrium Constants. then (at constant temperature) [C] c. [D] d = a constant, ( K c )
Chemical Equilibrium 1 The Equilibrium Law States If the concentrations of all the substances present at equilibrium are raised to the power of the number of moles they appear in the equation, the product
More informationNOTE: WORK FOR QUESTIONS 1, 2 and 9 ARE HANDWRITTEN AND FOUND IN THE LAST PAGES OF THIS DOCUMENT. 1. For the following equilibrium CH 3.
WorkSheet 4 key Equilibrium NOTE: WORK FOR QUESTIONS 1, 2 and 9 ARE HANDWRITTEN AND FOUND IN THE LAST PAGES OF THIS DOCUMENT. 1. For the following equilibrium CH 3 COOH(aq) CH 3 COO (aq) + H + (aq) if
More informationChemical Kinetics and Equilibrium
Chemical Kinetics and Equilibrium 1 Which statement incorrectly describes a chemical reaction approaching equilibrium? As a chemical reaction approaches equilibrium, the net change in the amount of reactants
More informationChemical Equilibrium. Chapter 8
Chemical Equilibrium Chapter 8 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 are
More informationUnit 2 Pre-Test Reaction Equilibrium
Unit 2 Pre-Test Reaction Equilibrium Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Consider the following equilibrium system: 2HF(g) F 2(g) + H 2 (g)
More informationChapter 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, 15.17-15.91, 15.94-99, 15.10-15.103 Example: Ice melting is a dynamic process:
More informationChemical 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 informationChapter 13: Chemical Equilibrium
Chapter 13: Chemical Equilibrium 13.1 The Equilibrium Condition Equilibrium: a state in which no observable changes occur H 2 O (l) H 2 O (g) Physical equilibrium: no chemical change. N 2(g) + 3H 2(g)
More informationInitial amounts: mol Amounts at equilibrium: mol (5) Initial amounts: x mol Amounts at equilibrium: x mol
4. CHEMICAL EQUILIBRIUM n Equilibrium Constants 4.1. 2A Y + 2Z Initial amounts: 4 0 0 mol Amounts at equilibrium: 1 1.5 3.0 mol Concentrations at equilibrium: 1 5 1.5 5 3.0 5 mol dm 3 K c (1.5/5) (3.0/5)2
More informationChapter 15 Equilibrium
Chapter 15. Chemical Equilibrium Common Student Misconceptions Many students need to see how the numerical problems in this chapter are solved. Students confuse the arrows used for resonance ( )and equilibrium
More informationChemical Equilibrium
Chemical Equilibrium What is equilibrium? Expressions for equilibrium constants, K eq ; Calculating K eq using equilibrium concentrations; Factors that affect equilibrium; Le Chatelier s Principle What
More informationChemical Equilibria. OCR Chemistry A H432
Chemical Equilibria Chemical equilibrium is a dynamic equilibrium. Features of a dynamic equilibrium, which can only be established in a closed system (nothing added or removed): - rates of forward and
More informationChemistry 12: Dynamic Equilibrium Practice Test
Chemistry 12: Dynamic Equilibrium Practice Test A. Multiple Choice: For each question, select the best answer and record your choice on the answer key provided. /25 1) A system at equilibrium is said to
More informationCHEM J-8 June /01(a) With 3 C-O bonds and no lone pairs on the C atom, the geometry is trigonal planar.
CHEM1001 2014-J-8 June 2014 22/01(a) What is the molecular geometry of the formate ion? Marks 7 With 3 C-O bonds and no lone pairs on the C atom, the geometry is trigonal planar. Write the equilibrium
More informationThe Factors that Determine the Equilibrium State
The Factors that Determine the Equilibrium State The equilibrium state (or the ratio of products to reactants) is determined by two factors: 1. Energy Systems tend to move toward a state of minimum potential
More informationLe Châtelier's Principle. Chemical Equilibria & the Application of Le Châtelier s Principle to General Equilibria. Using Le Châtelier's Principle
Chemical Equilibria & the Application of Le Châtelier s Principle to General Equilibria CHEM 107 T. Hughbanks Le Châtelier's Principle When a change is imposed on a system at equilibrium, the system will
More informationEquilibrium. What is equilibrium? Hebden Unit 2 (page 37 69) Dynamic Equilibrium
Equilibrium What is equilibrium? Hebden Unit (page 37 69) Dynamic Equilibrium Hebden Unit (page 37 69) Experiments show that most reactions, when carried out in a closed system, do NOT undergo complete
More informationChapter 18. Reversible Reactions. A chemical reaction in which the products can react to re-form the reactants is called a reversible reaction.
Section 1 The Nature of Chemical Equilibrium Reversible Reactions A chemical reaction in which the products can react to re-form the reactants is called a reversible reaction. Section 1 The Nature of Chemical
More informationChemical Equilibrium. Equilibrium Constant
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 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 informationInitial amounts: mol Amounts at equilibrium: mol (5) Initial amounts: x mol Amounts at equilibrium: x mol
4. CHEMICAL EQUILIBRIUM n Equilibrium Constants 4.1. A Y + Z Initial amounts: 4 0 0 mol Amounts at equilibrium: 1 1.5 3.0 mol Concentrations at equilibrium: 1 5 1.5 5 3.0 5 mol dm 3 K c (1.5/5) (3.0/5)
More information! 94
! 94 4 : - : : / : : : : ( :) : : : - : / : / : : - 4 : -4 : : : : : -5 () ( ) : -6 : - - : : : () : : : :4 : -7. : : -8. (. : ( : -9 : ( ( ( (5 (4 4 : -0! : ( : ( :. : (. (. (. (4. ( ( ( : ( 4 : - : :
More informationENTHALPY, ENTROPY AND FREE ENERGY CHANGES
ENTHALPY, ENTROPY AND FREE ENERGY CHANGES Refer to the following figures for Exercises 1-6. The lines on the vertical axis represent the allowed energies. Assume constant spacing between levels to determine
More informationChemical Equilibrium. Chapter
Chemical Equilibrium Chapter 14 14.1-14.5 Equilibrium Equilibrium is a state in which there are no observable changes as time goes by. Chemical equilibrium is achieved when: 1.) the rates of the forward
More informationc) Explain the observations in terms of the DYNAMIC NATURE of the equilibrium system.
Chemical Equilibrium - Part A: 1. At 25 o C and 101.3 kpa one mole of hydrogen gas and one mol of chlorine gas are reacted in a stoppered reaction vessel. After a certain time, three gases are detected
More informationEquilibrium and Reaction Rate
Equilibrium and Reaction Rate Multiple Choice Questions - Answers 1. Activation energy could be considered as the minimum energy required to do which of these? A. change the orientation of the reactant
More informationChapter Outline. The Dynamics of Chemical Equilibrium
Chapter Outline 14.1 The Dynamics of Chemical Equilibrium 14.2 Writing Equilibrium Constant Expressions 14.3 Relationships between K c and K p Values 14.4 Manipulating Equilibrium Constant Expressions
More informationPC-1(A): PHASE EQULIBRIUM: SYNOPSIS
PC-1(A):Phase equilibrium-synopsis; Dr. A. DAYALAN, Professor of Chemistry 1 PC-1(A): PHASE EQULIBRIUM: SYNOPSIS 1 PHASE (P)-Physically distinct and mechanically separable 2 COMPONENTS (C) Number of chemically
More informationCHEMISTRY 12 UNIT II EQUILIBRIUM D Learning Goals
CHEMISTRY 12 UNIT II EQUILIBRIUM D Learning Goals 1. Chemical equilibrium is said to by dynamic because a. The reaction proceeds quickly b. The mass of the reactants is decreasing c. The macroscopic properties
More informationAP Study Questions
Class: Date: AP 19.5-19.7 Study Questions Multiple Choice Identify the choice that best completes the statement or answers the question. 3. The value of G at 25 C for the formation of POCl 3 from its constituent
More informationX212F Which of the following is a weak base in aqueous solution? A) H 2 CO 3 B) B(OH) 3 C) N 2 H 4 D) LiOH E) Ba(OH) 2
PX212SP14 Practice Exam II / Spring 2014 1. Which of the following statements are characteristic of acids? 1. They are proton donors. 2. They react with bases to produce a salt and water. 3. They taste
More informationCHEM 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 information15.1 The Concept of Equilibrium
Lecture Presentation Chapter 15 Chemical Yonsei University 15.1 The Concept of N 2 O 4 (g) 2NO 2 (g) 2 Chemical equilibrium occurs when a reaction and its reverse reaction proceed at the same rate. The
More informationChemical Equilibrium
Chemical Equilibrium Concept of Equilibrium Equilibrium Constant Equilibrium expressions Applications of equilibrium constants Le Chatelier s Principle The Concept of Equilibrium The decomposition of N
More informationChapter 13: Chemical Equilibrium
Chapter 13: Chemical Equilibrium May 5 2:04 PM 13.1 The Equilibrium Condition When you finish this section you will be able to list some characteristics of reactions at equilibrium. Chemical equilibrium
More informationProjektovanje paralelnih algoritama II
Projektovanje paralelnih algoritama II Primeri paralelnih algoritama, I deo Paralelni algoritmi za množenje matrica 1 Algoritmi za množenje matrica Ovde su data tri paralelna algoritma: Direktan algoritam
More informationChem 1B, Test Review #2
1. The following kinetics data were obtained for the reaction: Expt.# 2NO(g) + Cl 2 (g) 2NOCl(g) [NO] 0 (mol/l) [Cl 2 ] 0 (mol/l) Initial Rate, (mol/l.s) 1 0.20 0.10 6.3 x 10 3 2 0.20 0.30 1.9 x 10 2 3
More informationwhich has an equilibrium constant of Which of the following diagrams represents a mixture of the reaction at equilibrium?
Chapter 9 Quiz: Chemical Equilibria 1. Which of the following statements is true regarding chemical equilibrium? I. The concentrations of reactants and products at equilibrium are constant, which means
More informationChapter 6: Chemical Equilibrium
Chapter 6: Chemical Equilibrium 6.1 The Equilibrium Condition 6. The Equilibrium Constant 6.3 Equilibrium Expressions Involving Pressures 6.4 The Concept of Activity 6.5 Heterogeneous Equilibria 6.6 Applications
More informationChapter 15. Chemical Equilibrium
Chapter 15. Chemical Equilibrium 15.1 The Concept of Equilibrium Consider colorless frozen N 2 O 4. At room temperature, it decomposes to brown NO 2. N 2 O 4 (g) 2NO 2 (g) At some time, the color stops
More informationName: Kinetics & Thermodynamics Date: Review
Name: Kinetics & Thermodynamics Date: Review 1. What is required for a chemical reaction to occur? A) standard temperature and pressure B) a catalyst added to the reaction system C) effective collisions
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 informationGas 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 informationEQUILIBRIUM. Opposing reactions proceed at equal rates Concs. of reactants & products do not change over time
EQUILIBRIUM Opposing reactions proceed at equal rates Concs. of reactants & products do not change over time Examples: vapor pressure above liquid saturated solution Now: equilibrium of chemical reactions
More informationThe Equilibrium State. Chapter 13 - Chemical Equilibrium. The Equilibrium State. Equilibrium is Dynamic! 5/29/2012
Chapter 13 - Chemical Equilibrium The Equilibrium State Not all chemical reactions go to completion; instead they attain a state of equilibrium. When you hear equilibrium, what do you think of? Example:
More informationUnit 8 Topic 7: Equilibrium CDO IB Chemistry SL
Unit 8 Topic 7: Equilibrium CDO IB Chemistry SL Assessment Statements 7.1 Dynamic Equilibrium 7.1.1 Outline the characteristics of chemical and physical systems in a state of equilibrium 7.2 The position
More informationChemical Equilibrium. A state of no net change in reactant & product concentrations. There is a lot of activity at the molecular level.
Chemical Equilibrium A state of no net change in reactant & product concentrations. BUT There is a lot of activity at the molecular level. 1 Kinetics Equilibrium For an elementary step in the mechanism:
More informationChemistry B11 Chapter 5 Chemical reactions
Chapter 5 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 A + BC AC +
More information(i.e., equilibrium is established) leads to: K = k 1
CHEMISTRY 104 Help Sheet #8 Chapter 12 Equilibrium Do the topics appropriate for your lecture http://www.chem.wisc.edu/areas/clc (Resource page) Prepared by Dr. Tony Jacob Nuggets: Equilibrium Constant
More information8. Relax and do well.
CHEM 1515 Exam II John II. Gelder October 14, 1993 Name TA's Name Lab Section INSTRUCTIONS: 1. This examination consists of a total of 8 different pages. The last two pages include a periodic table, a
More informationChapter Test B. Chapter: Chemical Equilibrium. following equilibrium system? 2CO(g) O 2 (g) ^ 2CO 2 (g)
Assessment Chapter Test B Chapter: Chemical Equilibrium PART I In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. What is
More informationI. Multiple Choice Questions (Type-I)
I. Multiple Choice Questions (Type-I) 1. Thermodynamics is not concerned about. (i) energy changes involved in a chemical reaction. the extent to which a chemical reaction proceeds. the rate at which a
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 informationThermodynamics Review 2014 Worth 10% of Exam Score
Thermodynamics Review 2014 Worth 10% of Exam Score Name: Period: 1. Base your answer to the following question on the diagram shown below. 4. The heat of combustion for is kcal. What is the heat of formation
More informationM11/4/CHEMI/SPM/ENG/TZ2/XX CHEMISTRY STANDARD LEVEL PAPER 1. Monday 9 May 2011 (afternoon) 45 minutes INSTRUCTIONS TO CANDIDATES
M11/4/CHEMI/SPM/ENG/TZ/XX 116116 CHEMISTRY STANDARD LEVEL PAPER 1 Monday 9 May 011 (afternoon) 45 minutes INSTRUCTIONS TO CANDIDATES Do not open this examination paper until instructed to do so. Answer
More informationCHEM Dr. Babb s Sections Lecture Problem Sheets
CHEM 116 - Dr. Babb s Sections Lecture Problem Sheets Kinetics: Integrated Form of Rate Law 61. Give the integrated form of a zeroth order reaction. Define the half-life and find the halflife for a general
More informationOFB Chapter 7 Chemical Equilibrium
OFB Chapter 7 Chemical Equilibrium 7-1 Chemical Reactions in Equilibrium 7-2 Calculating Equilibrium Constants 7-3 The Reaction Quotient 7-4 Calculation of Gas-Phase Equilibrium 7-5 The effect of External
More informationFinal Exam Chem 260 (12/20/99) Name (printed) Signature
Final Exam Chem 260 (12/20/99) Name (printed) Signature 1. For the reaction, (14 pts total) C(graph) + CO 2 (g) 2 CO(g) (a) Write the equilibrium constant expression: (2 pts) K = P CO 2 P CO2 (b) Using
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 informationCHAPTER 7: Chemical Equilibrium
CHAPTER 7: Chemical Equilibrium Chemical Reactions and Equilibrium Calculating Equilibrium Constants The Reaction Quotient Calculation of Gas-Phase Equilibria The effect of External Stresses: Le Châtelier
More information7. A solution has the following concentrations: [Cl - ] = 1.5 x 10-1 M [Br - ] = 5.0 x 10-4 M
Solubility, Ksp Worksheet 1 1. How many milliliters of 0.20 M AlCl 3 solution would be necessary to precipitate all of the Ag + from 45ml of a 0.20 M AgNO 3 solution? AlCl 3(aq) + 3AgNO 3(aq) Al(NO 3)
More informationH = DATA THAT YOU MAY USE. Units Conventional Volume ml or cm 3 = cm 3 or 10-3 dm 3 Liter (L) = dm 3 Pressure atm = 760 torr = 1.
DATA THAT YOU MAY USE Units Conventional S.I. Volume ml or cm 3 = cm 3 or 10-3 dm 3 Liter (L) = dm 3 Pressure atm = 760 torr = 1.013 10 5 Pa torr = 133.3 Pa Temperature C 0 C = 73.15 K PV L-atm = 1.013
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 informationChemical Equilibrium. Chemical Equilibrium. Chemical Equilibrium. Chemical Equilibrium. Equilibrium Constant. Equilibrium Constant
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 informationThe. Equilibrium. Constant. Chapter 15 Chemical Equilibrium. The Concept of Equilibrium. The Concept of Equilibrium. A System at Equilibrium
The Concept of Chapter 15 Chemical AP Chemistry 12 North Nova Education Centre 2017 Chemical equilibrium occurs when a reaction and its reverse reaction proceed at the same rate. The Concept of As a system
More informationPhysical Chemistry I Exam points
Chemistry 360 Fall 2018 Dr. Jean M. tandard October 17, 2018 Name Physical Chemistry I Exam 2 100 points Note: You must show your work on problems in order to receive full credit for any answers. You must
More information8. Relax and do well.
CHEM 1314.05 Exam II John II. Gelder October 18, 1994 Name TA's Name Lab Section INSTRUCTIONS: 1. This examination consists of a total of 9 different pages. The last three pages include a periodic table,
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 information2nd- Here's another example of a reversible reaction - dissolving salt in a beaker of water, described by the following reaction: NaCl (s)
CHEMICAL EQUILIBRIUM AP Chemistry (Notes) Most chemical processes are reversible. Reactants react to form products, but those products can also react to form reactants. Examples of reversible reactions:
More informationQuestions 1-3 relate to the following reaction: 1. The rate law for decomposition of N2O5(g) in the reaction above. B. is rate = k[n2o5] 2
Questions 1-3 relate to the following reaction: 2N2O5(g) 4NO2(g) + O2(g) 1. The rate law for decomposition of N2O5(g) in the reaction above A. is rate = k[n2o5] B. is rate = k[n2o5] 2 C. is rate = [NO2]
More informationNajbrži procesi Prenos elektrona Prenos H atoma Prenosi drugih atoma izmedju molekula DNK sinteza. dc dt
HEMIJSKA KINETIKA - kojom brzinom se reakcija odvija. - kakav je mehanizam hemijske reakcije koji su koraci koji se dogode tokom promene reaktanata ka produktima. - zajedno sa izučavanjem ravnoteže i termodinamičkih
More informationAnswers to Problem Sheet (a) spontaneous (b) nonspontaneous (c) nonspontaneous (d) spontaneous (e) nonspontaneous
Answers to Problem Sheet 5 1. (a) spontaneous (b) nonspontaneous (c) nonspontaneous (d) spontaneous (e) nonspontaneous 2. (a) Heat will flow from the warmer block of iron to the colder block of iron until
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 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 information30 Zn(s) 45 Rh. Pd(s) Ag(s) Cd(s) In(s) Sn(s) white. 77 Ir. Pt(s) Au. Hg(l) Tl. 109 Mt. 111 Uuu. 112 Uub. 110 Uun. 65 Tb. 62 Sm. 64 Gd. 63 Eu.
Enthalpy changes: experimentally it is much easier to measure heat flow at const pressure - this is enthalpy q p = )H : also nearly all chemical reactions are done at constant pressure. Enthalpy (heat)
More informationCHEMICAL EQUILIBRIUM -2
CHEMICAL EQUILIBRIUM - 1. The gaseous reaction A + B C + D + heat, has reached equilibrium. It is possible to make the reaction to proceed forward 1) by adding more of C ) by adding more of D 3) by raising
More informationCHEM 108 (Spring-2008) Exam. 3 (105 pts)
CHEM 08 (Spring-008) Exam. (05 pts) Name: --------------------------------------------------------------------------, CLID # -------------------------------- LAST NAME, First (Circle the alphabet segment
More informationAIR CURTAINS VAZDU[NE ZAVESE V H
AIR CURTAINS V 15.000 H 21.000 KLIMA Co. 2 KLIMA Co. Flow and system stress should be known factors in air flow. The flow is gas quantity flowing through the system during given time unit and is measured
More information10.02 PE Diagrams. 1. Given the equation and potential energy diagram representing a reaction:
10.02 PE Diagrams 1. Given the equation and potential energy diagram representing a reaction: 3. Given the potential energy diagram and equation representing the reaction between substances A and D : If
More informatione) KC = [H + ] [HCOO - ] Kp = no expression [HCOOH]
Problems - Chapter 15 (with solutions) 1) What is the significance of the equilibrium constant? What does a large equilibrium constant tell us about a reaction? A small one? The equilibrium constant tells
More information33. a. Heat is absorbed from the water (it gets colder) as KBr dissolves, so this is an endothermic process.
31. This is an endothermic reaction so heat must be absorbed in order to convert reactants into products. The high temperature environment of internal combustion engines provides the heat. 33. a. Heat
More informationLab Day and Time: Instructions. 1. Do not open the exam until you are told to start.
Name: Lab Day and Time: Instructions 1. Do not open the exam until you are told to start. 2. This exam is closed note and closed book. You are not allowed to use any outside material while taking this
More informationEquilibrium & Reaction Rate
Equilibrium & Reaction Rate 1. One of the important reactions in coal gasification is the catalytic methanation reaction: CO(g) + H (g) H O(g) + CH 4 (g) H 06 kj a) Predict the direction in which this
More informationFORMULA SHEET (tear off)
FORMULA SHEET (tear off) N A = 6.022 x 10 23 C = ( 5 / 9 ) ( F - 32) F = ( 9 / 5 )( C) + 32 1 amu = 1.661 x 10-27 kg C = K - 273.15 K = C + 273.15 1 atm = 760 torr = 760 mm Hg 1 atm = 1.013 bar pv = nrt
More informationGeneral Chemistry revisited
General Chemistry revisited A(g) + B(g) C(g) + D(g) We said that G = H TS where, eg, H = f H(C) + f H(D) - f H(A) - f H(B) G < 0 implied spontaneous to right G > 0 implied spontaneous to left In a very
More informationCHEMICAL EQUILIBRIUM. Chapter 15
Chapter 15 P a g e 1 CHEMICAL EQUILIBRIUM Examples of Dynamic Equilibrium Vapor above a liquid is in equilibrium with the liquid phase. rate of evaporation = rate of condensation Saturated solutions rate
More informationQuiz B3: Le Chatelier s Principle Block:
Quiz B3: Le Chatelier s Principle Name: Block: 1. Consider the following reaction: 2SO2(g) + O2(g) 2SO3(g) H = -197 kj/mol Which of the following will not shift the equilibrium to the right? A. Adding
More informationChapter 15 Chemical Equilibrium
Equilibrium To be in equilibrium is to be in a state of balance: Chapter 15 Chemical Equilibrium - Static Equilibrium (nothing happens; e.g. a tug of war). - Dynamic Equilibrium (lots of things happen,
More information