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Key Concepts PowerPoint

Chapter 13
Chemical Equilibrium

  
13-00-01UN
Title
 Decomposition of N2O4
Caption
 The decomposition of the colorless gas dinitrogen tetroxide (N2O4) to the dark brown gas nitrogen dioxide (NO2).
Notes
 Equilibrium between N2O4 and NO2
Keywords
 decomposition, N2O4
13-01
Title
 Initial concentration and equilibrium
Caption
 Figure 13.1 Change in the concentrations of N2O4 and NO2 with time in two experiments at 25°C: (a) Only N2O4 is present initially; (b) only NO2 is present initially. In experiment (a), [NO2] increases as [N2O4] decreases. In experiment (b), [N2O4] increases as [NO2] decreases. In both experiments, a state of chemical equilibrium is reached when the concentrations level off at constant values: [N2O4] = 0.0337 M; [NO2] = 0.0125 M.
Notes
 The experiments demonstrate that the reaction is reversible and proceeds in a way to achieve and maintain an equilibrium state.
Keywords
 initial concentrations, reversible reaction
13-02
Title
 Equilibrium as a dynamic state
Caption
 Figure 13.2 Rates of the forward and reverse reactions for decomposition of N2O4 to NO2. As N2O4 is consumed, the rate of the forward reaction decreases; as NO2 is formed, the rate of the reverse reaction increases. When the two rates become equal, an equilibrium state is attained and there are no further changes in concentrations.
Notes
 At equilibrium, the rates of the forward and reverse reactions are equal.
Keywords
 dynamic state, forward reaction, reverse reaction
13-02-01UN
Title
 Equilibrium equation
Caption
 Equilibrium expression for determining the equilibrium constant, Kc, for the general reversible reaction aA +bB <=> cC +dD.
Notes
 Equilibrium equation for determining the equilibrium constant
Keywords
 equilibrium constant, equilibrium expression
13-02-04UN
Title
 Key Concept Example 13.4
Caption
 For the reversible reaction A <=> B, A molecules (red spheres) interconvert with B molecules (blue spheres), mixture (1) represents the system at equilibrium.
Notes
 Key concept example 13.4
Keywords
 key concept, equilibrium concentration
13-02-05UN
Title
 Key Concept Problem 13.4
Caption
 The following pictures represent mixtures that contain A atoms (red), B atoms (blue), and AB and B2 molecules.
Notes
 Key concept problem 13.4
Keywords
 key concept, equilibrium concentrations
13-02-06UN
Title
 Synthesis of hydrogen iodide
Caption
 One mole of hydrogen and one mole of iodine react in a reversible fashion to produce two moles of hydrogen iodide.
Notes
 Since the reaction has two moles of gas on both sides of the equation, Kp is equal to Kc.
Keywords
 equilibrium constants
13-02-07UN
Title
 Worked Example 13.5
Caption
 Methane reacts with hydrogen sulfide to produce carbon disulfide and hydrogen in a reversible reaction.
Notes
 Worked Example 13.5
Keywords
 Kp, equilibrium constant
13-02-09UN
Title
 Worked Example 13.6
Caption
 Water and methane react reversibly, producing carbon monoxide and hydrogen.
Notes
 Worked Example 13.6
Keywords
 Kp, Kc, equilibrium constants
13-03
Title
 Decomposition of calcium carbonate
Caption
 Figure 13.3 Thermal decomposition of calcium carbonate: CaCO3(s) <=> CaO(s) +CO2(g). At the same temperature, the equilibrium pressure of CO2 (measured with a closed-end manometer) is the same in (a) and (b), independent of how much solid CaCO3 and CaO are present.
Notes
 Heterogeneous equilibrium
Keywords
 heterogeneous equilibrium, equilibrium constant
13-04
Title
 Extent of reaction
Caption
 Figure 13.4 Judging the extent of a reaction. The larger the value of the equilibrium constant Kc, the farther the reaction proceeds to the right before reaching the equilibrium state.
Notes
 Using the equilibrium constant to determine if the forward or reverse reaction is favored.
Keywords
 equilibrium constant, extent of reaction
13-05
Title
 Using the reaction quotient
Caption
 Figure 13.5 Predicting the direction of reaction. The direction of reaction depends on the relative values of Qc and Kc.
Notes
 If Qc < Kc, the reaction goes from left to right If Qc = Kc, the reaction is at equilibrium If Qc > Kc, the reaction goes from right to left
Keywords
 reaction quotient, equilibrium constant
13-05-01UN
Title
 Key Concept Problem 13.10
Caption
 The following pictures represent reaction mixtures that contain A2 molecules (red), B2 molecules (blue), and AB molecules.
Notes
 Key Concept Problem 13.10
Keywords
 reaction quotient, equilibrium constant
13-06
Title
 Calculating equilibrium concentrations
Caption
 Figure 13.6 Steps to follow in calculating equilibrium concentrations from initial concentrations.
Notes
 Calculating equilibrium concentrations from initial concentrations
Keywords
 equilibrium concentrations
13-07
Title
 The Haber Process
Caption
 Figure 13.7 Representation of the Haber process for the industrial production of ammonia. A mixture of gaseous N2 and H2 at 130-300 atm pressure is passed over a catalyst at 400-500°C, and ammonia is produced by the reaction N2(g) +3 H2(g) <=> 2 NH3(g). The NH3 in the gaseous mixture of reactants and products is liquefied, and the unreacted N2 and H2 are recycled.
Notes
 The production of ammonia by the Haber process
Keywords
 Haber process
13-08
Title
 Changes in concentration
Caption
 Figure 13.8 Changes in concentrations when N2 is added to an equilibrium mixture of N2, H2, and NH3. Net conversion of N2 and H2 to NH3 occurs until a new equilibrium is established. That is, N2 and H2 concentrations decrease, while the NH3 concentration increases.
Notes
 If a change in concentration is made, a system initially at equilibrium will shift the direction of reaction in order to maintain equilibrium.
Keywords
 change in concentration, Le Chätelier
13-11
Title
 Effect of pressure and volume
Caption
 Figure 13.11 Qualitative effect of pressure and volume on the equilibrium N2(g) +3 H2(g) <=> 2 NH3(g). (a) A mixture of gaseous N2, H2, and NH3 at equilibrium. (b) When the pressure is increased by decreasing the volume, the mixture is no longer at equilibrium (Qc < Kc). (c) Reaction occurs from left to right, decreasing the total number of gaseous molecules until equilibrium is re-established (Qc = Kc).
Notes
 For systems involving gaseous species, the equilibrium of the reaction system is affected by changes in pressure and volume.
Keywords
 Le Chätelier, volume, pressure
13-11-01UN
Title
 Key Concept Problem 13.18
Caption
 The following picture represents the equilibrium mixture for the gas-phase reaction A2 <=> 2 A.
Notes
 Key Concept Problem 13.18
Keywords
 Key Concept Problem 13.18
13-12
Title
 Changes in Temperature
Caption
 Figure 13.12 Temperature dependence of the equilibrium constant for the reaction N2(g) +3 H2(g) <=> 2 NH3(g). Note that Kc is plotted on a logarithmic scale and decreases by a factor of 1011 on raising the temperature from 300 K to 1000 K.
Notes
 Reaction rates are temperature dependent. Since equilibrium is based on rates of forward and reverse reactions, equilibrium is also temperature dependent.
Keywords
 Le Chätelier, temperature, enthalpy
13-13-02UN
Title
 Key Concept Problem 13.21
Caption
 The following pictures represent the composition of a heterogeneous equilibrium system at 300 K and 400 K.
Notes
 Key Concept Problem 13.21
Keywords
 key concept, heterogeneous, Le Chätelier, enthalpy
13-14
Title
 Effect of a catalyst
Caption
 Figure 13.14 Potential energy profiles for a reaction whose activation energy is lowered by the presence of a catalyst. The activation energy for the catalyzed pathway (red curve) is lower than that for the uncatalyzed pathway (blue curve) by an amount DEa. The catalyst lowers the activation energy barrier for the forward and reverse reactions by exactly the same amount. The catalyst therefore accelerates the forward and reverse reactions by the same factor, and the composition of the equilibrium mixture is unchanged.
Notes
 Catalysts affect the rates of both the forward and reverse reaction, so they do not affect the equilibrium of the system, just the rate at which the system attains equilibrium.
Keywords
 catalyst
13-14-02
Title
 Structure of heme
Caption
 Heme—an O2 molecule binds to the central iron atom.
Notes
 Heme is the molecule that allows the transport of oxygen from the lungs to the other parts of the body.
Keywords
 heme, oxygen transport
13-15
Title
 Saturation curve for heme
Caption
 Figure 13.15 An oxygen-carrying curve for hemoglobin. The percent saturation of the oxygen-binding sites on hemoglobin depends on the partial pressure of oxygen (PO2).
Notes
 Percent saturation of oxygen in hemoglobin as a function of oxygen partial pressure.
Keywords
 heme, oxygen saturation, partial pressure
13-15-010
Title
 Key Concept Summary
Caption
 Chemical equilibrium key concept summary.
Notes
 Key concept summary for Chapter 13
Keywords
 key concept, summary
13-15-02UN
Title
 Key Concept Problem 13.28
Caption
 Consider the interconversion of A molecules (red spheres) with B molecules (blue spheres). Each of the following series of pictures represents a separate experiment in which time increases from left to right.
Notes
 Key Concept Problem 13.28
Keywords
 key concept, equilibrium constant
13-15-03UN
Title
 Key Concept Problem 13.29
Caption
 The following pictures represent the equilibrium state for three reactions of the type: A2 +X2 <=> 2 AX.
Notes
 Key Concept Problem 13.29
Keywords
 key concept, equilibrium constant
13-15-07UN
Title
 Key Concept Problem 13.33
Caption
 The following pictures represent the composition of the equilibrium system A +B <=> AB at 300 K and at 400 K.
Notes
 Key Concept Problem 13.33
Keywords
 key concept, Le Chätelier, temperature
13-15-11UN
Title
 Key Concept Problem 13.37
Caption
 The following picture represents the equilibrium state for the reaction 2 AB <=> A2 +B2.
Notes
 Key Concept Problem 13.37
Keywords
 key concept, rate constants
13-TB01
Title
 Table 13.1 Concentration Data at 25°C for the Reaction
Caption
Notes
Keywords
13-TB01.01UN
Title
 2 HI(g)
Caption
 2 HI(g)
Notes
Keywords
13-TB01.02UN
Title
 FeO(s) CO(g) Fe(s)
Caption
 FeO(s) CO(g) Fe(s)
Notes
Keywords
13-TB02
Title
 Table 13.2 Partial Pressure of Oxygen in the Lungs and Blood at Sea Level
Caption
Notes
Keywords
13-TB02.01UN
Title
 Temperature (K)
Caption
 Temperature (K)
Notes
Keywords
13-TB02.02UN
Title
 Temperature (K)
Caption
 Temperature (K)
Notes
Keywords
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