Ch.14 - Chemical EquilibriumWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Thermodynamics and Le Chatelier’s Principle

Concept #1: Understanding Le Chatelier’s Principle. 

According to Le Chatelier’s Principle if a system (chemical reaction) is at equilibrium and we disturb it then the system will readjust to maintain it’s equilibrium state.

Example #1: The following is an endothermic reaction where Kc = 6.73 x 103.

For each of the choices below predict in which direction the reaction will proceed.

Practice: Consider the reaction below:

CH4 (g)  +  F2 (g)  ⇌  CF4 (g)  + HF (g)   H = + 38.1 KJ/mol

The following changes will shift the equilibrium to the left except one. Which one would not cause a shift to the left?


Practice: The following data was collected for the following reaction at equilibrium 

2 A (g) + 3 B (g)  ⇌ C (g)     

At 25 oC K is 5.2 x 10-4 and at 50 oC K is 1.7 x 10-7. Which of the following statements is true?

a) The reaction is exothermic.

b) The reaction is endothermic.

c) The enthalpy change, ΔH, is equal to zero.

d) Not enough information is given. 

When looking at a chemical reaction we look at the two concepts of Kinetics and Thermodynamics to get a total view. However, remember that Le Chatelier’s Principle deals with Thermodynamics and not Kinetics. 

Practice: Which direction will the following reaction (in a 10.0 L flask) proceed if a catalyst is added to the system? 

CaCO3 (s)  ⇌ CaO (s) + CO2 (g)            Kp = 3.2 x 10-28


Practice: Consider the following gas reaction of A2 ( shaded spheres) and B2 ( unshaded spheres)

A2 (g)  +  B(g)  ⇌  2 AB (g) 

Which container proceeds more to completion? 

Additional Problems
Consider the following reactions at equilibrium. In which cases will the reaction proceed to the right by decreasing the pressure? a) 1, 2, 3 b) 2, 3, 4 c) 3, 4, 5 d) 2, 3, 5 e) 1, 3, 4
For the following reaction, which condition will shift the equilibrium to the right? a) increasing the temperature b) increasing the pressure c) adding a catalyst d) adding more water e) more than one of the above is correct
Consider the endothermic reaction shown below. Choose the change that would shift the equilibrium toward the reactants. C2H4(g) + I2(g) ⇌ C2H4I2(g) A) Adding I2 to the reaction mixture. B) Adding C2H4 to the reaction mixture. C) Increasing the reaction volume. D) Increasing the reaction temperature. E) Removing C2H4I2.
Consider the following reaction at equilibrium 6A (s) + 7B (g) ⇌ 5C (g) + 8D (l)           ΔH = -3226.6 kJ/mol Which one of the following statements is correct? A. Increasing the temperature would shift the reaction right. B. Increasing the temperature would decrease the value of K. C. Increasing the total pressure on the system would cause the reaction to shift left.  D. Adding a catalyst would favor the forward reaction, causing the reaction to shift right. E. Adding some A would cause the reaction to shift right.
What happens to the concentration of NO(g) when the total pressure on the reaction below is increased (by compression) when it is at equilibrium? 3NO2(g) + H2O(l) ⇌ 2HNO3(aq) + NO(g) it increases it decreases it remains the same it is impossible to tell
Consider the system: 2 N2O5(g) ⇌ 2N2O4(g) + O2(g) at equilibrium at 25°C. If this is an exothermic reaction and the temperature was raised, would the equilibrium be shifted to produce more N2O5 or more N2O4? it is impossible to tell there would be no change more  N2O5 more N2O4
Consider the reaction: 2SO2 (g) + O2 (g) ⇌ 2SO3 (g) ΔH = -198.2 kJ/mol. What would be the effect on the reaction if we were to: a. increase the temperature b. increase the pressure c. increase [SO2] d. add a catalyst  
H2(g) is an important fuel source for hydrogen powered vehicles and a reagent for the Haber-Bosch process. A majority of H2 is generated using equilibrium below. C(s) + H2O(g) ⇌ CO(g) + H2(g)    ΔH°=131kJ/mol a) Write an equilibrium expression for this reaction.   b) predict the direction the equilibrium shifts (circle one) as a result of: 1. adding H2     left/reactants   right/products no change 2. removing CO   left/reactants   right/product  no change 3. adding more C left/reactants   right/product  no change 4. increasing temperature left/reactants   right/product  no change 5. increasing the pressure (by decreasing the volume) left/reactants   right/product  no change 6. increasing the pressure (by adding H2O) left/reactants   right/product  no change c) Which of the above disturbance/stresses/"pokes" will change the equilibrium constant (K)? Why? If none write "none".    
For a given reaction, which of the following statements can be made about the value of the equilibrium constant?     A)    It always remains the same.     B)    It increases when the concentration of one of the products is increased.     C)    It increases when the concentration of one of the reactants is increased.     D)    It changes with changes in the temperature.     E)    It can be changed by addition of a catalyst.  
Consider this gas-phase reaction. H2 (g) + I2 (g) ⇋ 2 HI (g)                Δ H = 53 kJ Which reaction characteristics will be affected by a change in temperature? 1. value of equilibrium constant 2. equilibrium concentrations a) 1 only b) 2 only c) 1 and 2 d) neither 1 nor 2    
For the reaction  CO(g) + 3H 2(g) ⇌ CH 4(g) + H 2O(g)          q = -206 kJ         What conditions favor maximum conversion of reactants to products?     A)    low pressure and low temperature     B)    removal of H 2(g) and low temperature     C)    high pressure and high temperature     D)    high pressure and low temperature     E)    low pressure and high temperature  
Ethane, C 2H 6, can be formed by reacting acetylene, C 2H 2, with hydrogen gas as follows:         C 2H 2(g) + H 2(g) ⇌ C 2H 6(g)   Exothermic         What change will be observed if the temperature of the reaction mixture at equilibrium were increased?     A)    The concentration of C 2H 6 will increase.     B)    The concentration of both C 2H 2 and H 2 will increase.     C)    The concentration of both C 2H 2 and H 2 will decrease.     D)    The concentration of H 2 only will decrease.     E)    There will be no change in the equilibrium concentrations.  
Now let’s consider the overall reaction as an equilibrium process, carried out at a lower temperature such that H 2O is obtained as a liquid. 2NO(g) + H 2(g) ⇌ N 2O(g) + H 2O(l) If we reduce the temperature even further, the equilibrium shifts to the right (more products, less reactants). Is this reaction endothermic or exothermic?
Which of the following changes in reaction conditions will alter the composition of an equilibrium mixture of gases? a) addition of reactants b) removal of products c) decreasing the pressure or the volume d) increasing the temperature e) all of the above
For the following reaction at equilibrium, which gives a change that will shift the position of equilibrium to favor formation of more products? 2NOBr (g) ⇌ 2NO (g) + Br2 (g), ΔH°rxn = -30 kJ/mol A. Increase the total pressure by decreasing the volume. B. Remove NO. C. Add more Br2. D. Raise the temperature. E. Remove NOBr
For the reaction below, which change in conditions made to a system at equilibrium will result in a net reaction to the right towards products? C(s) + 2 H2(g) ⇌ CH4(g)           ΔH  ̊=–74.8 kJ/mol a) Adding more C(s) b) Adding more H2(g) c) Raising the temperature d) a and b e) all the above  
Consider the following exothermic reaction. Which of the conditions will increase the value of the equilibrium constant, Kc? 4 NH3(g) + 5 O2(g) ⇌ 4 NO(g) + 6 H2O(g) a) adding more NH3 b) decreasing the temperature c) adding a catalyst d) increasing the system volume e) all of the above is correct
For an exothermic reaction, what would happen to the numerical value of Kc, if we increase the temperature at constant pressure? 1. Kc would not change. 2. Kc would either increase or decrease, depending on the number of moles of gas involved. 3. Kc would decrease. 4. Kc would increase. 5. Kc would either increase or decrease, depending on the concentrations.
The reaction for the synthesis of ammonia  N2(g) + 3H2(g) ⇌ 2NH3(g)  is exothermic. To obtain the greatest yield of NH3, this reaction should be carried out at 1. any temperature, any pressure. 2. high temperature, low pressure. 3. high temperature, high pressure. 4. low temperature, low pressure. 5. low temperature, high pressure.
C (s) + H 2O (g) → CO (g) + H 2 (g)             ∆H > 0 For the system above at equilibrium, which changes will increase the amount of H 2 (g)? I. Adding C(s) II. Increasing the volume of the container III. Increasing the temperature   A) I only               B) III only                   C) II and III only                     D) I, II and III  
Effect of temperature and pressure on NH3 yield in the Haber process. Each mixture was produced by starting with a 3:1 molar mixture of H2 and N2.At what combination of pressure and temperature should you run the reaction to maximize NH3 yield?
Explain what happens if a system at equilibrium is subject to one of the following changes and why:The temperature is raised.
Is vaporization an exothermic or endothermic process? Based on Le Chatelier’s principle, would you predict the vapor pressure of a gas will increase or decrease as the temperature increases?
What is the effect of a temperature change on a chemical reaction initially at equilibrium? How does the effect differ for an exothermic reaction compared to an endothermic one?
Acetic acid can be manufactured by combining methanol with carbon monoxide, an example of a carbonylation reaction: CH3 OH( l ) + CO( g )  →  3 COOH( l )Industrially, this reaction is run at temperatures above 25 oC. Will an increase in temperature produce an increase or decrease in the mole fraction of acetic acid at equilibrium?
The following diagramsrepresent equilibrium mixtures for the reaction A2 + B + AB at (a) 300 K and (b) 500 K. The A atoms are red, and the B atoms are blue.Is the reaction exothermic or endothermic?
How do the following changes affect the value of the equilibrium constant for a gas-phase exothermic reaction:decrease in the temperature
Water molecules in the atmosphere can form hydrogen-bonded dimers, (H2O) 2. The presence of these dimers is thought to be important in the nucleation of ice crystals in the atmosphere and in the formation of acid rain.The K p for water dimer formation in the gas phase is 0.050 at 300 K and 0.020 at 350 K. Is water dimer formation endothermic or exothermic?
Explain what happens if a system at equilibrium is subject to one of the following changes and why:A solid product is added.
If a reaction is carried out in the presence of a catalyst, will the amount of product present at equilibrium increase, decrease, or stay the same?
How do the following changes affect the value of the equilibrium constant for a gas-phase exothermic reaction:addition of a catalyst
At 1200 K, the approximate temperature of automobile exhaust gases (see the figure ), Kp for the reaction 2 CO2 (g) 2 CO(g) + O2 (g) is about 1 10 - 13.Based on your conclusion, would the CO concentration in the exhaust be decreased or increased by a catalyst that speeds up the reaction shown?
An equilibrium mixture of H2, I2, and HI at 458 oC contains 0.112 mol H2, 0.112 mol I2, and 0.775 mol HI in a 5.00-L vessel.What are the equilibrium partial pressure of HI when equilibrium is reestablished following the addition of 0.200 mol of HI?
Explain what happens if a system at equilibrium is subject to one of the following changes and why:The concentration of a reactant is increased.
What is the effect of a change in concentration of a reactant or product on a chemical reaction initially at equilibrium?
How do the following changes affect the value of the equilibrium constant for a gas-phase exothermic reaction:removal of a reactant
How do the following changes affect the value of the equilibrium constant for a gas-phase exothermic reaction:removal of a product
Explain what happens if a system at equilibrium is subject to one of the following changes and why:The volume is decreased.
What is the effect of a change in volume on a chemical reaction (that includes gaseous reactants or products) initially at equilibrium?
Consider the following equilibrium, for which H< 0 22 ( g ) + O2 ( g ) 23 ( g ) How will each of the following changes affect an equilibrium mixture of the three gases?the volume of the reaction vessel is doubled
How do the following changes affect the value of the equilibrium constant for a gas-phase exothermic reaction:decrease in the volume
Consider the hypothetical reaction A(g) 2B(g). A flask is charged with 0.76 atm of pure A, after which it is allowed to reach equilibrium at 0 oC. At equilibrium the partial pressure of A is 0.37 atm .What could we do to maximize the yield of B?
Consider this reaction at equilibrium: C(s) + H2O(g) ⇌ CO(g) + H2(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. a) C is added to the reaction mixture. b) H2O is condensed and removed from the reaction mixture. c) CO is added to the reaction mixture. d) The volume of the reaction increases.
The equilibrium constant of a certain reaction is experimentally determined at 200 K and 250 K and is found to be equal to 1010 and 1016, respectively. What can you say for certain about the reaction?1. nothing can be said for certain2. It is endothermic 3. It is exothermic4. It will become non-spontaneous at higher temperatures
What would you do in order to maximize the yield of SO 3 from the following reaction:2SO2(g) + O2(g) ⇌ 2SO3(g)      ΔH°= −197.8 kJa) Lower the temperature and add and inert gas to raise the pressure.b) Raise the temperature and increase the volume of the container.c) Decrease the volume of the container and lower the temperature.d) Raise the temperature and add a catalyst.e) Increase the volume of the container and lower the temperature. 
Silane (SiH4) has not been observed in the atmosphere of Saturn. The absence of silane is believed to be due to the reactionSiH4(g) + Mg(OH)2(g) + H2O(g) ⇌ MgSiO3(s) + 4H2(g)As the temperature is raised, the partial pressure of H2 increases. What does this tell you about the reaction?a) The number of moles of gas increases on going from reactant to productsb) The reaction is endothermicc) The reaction is exothermicd) The reaction is heterogeneous (involving more than one phase)e) Mg(OH)2 does not obey the ideal gas law
Which of the following procedures will shift the equilibrium reaction to the right?A (s) + 2 B (g) ⇌ 3 C (s) + D (g)   ΔH° = - 25.2kJA. cooling the reactionB. removing some BC. adding some DD. doubling the volumeE. removing some C   
What is a good statement of le Chatelier's Principle?a) When dealing with polar and non-polar substances "Like dissolves like".b) "Birds of a feather flock together" is a colloquial way to expess this Principle.c) " A system in equilibrium that is subjected to a stress reacts in a way that counteracts the stress"d) "Colligative properties are those that depend only on the number of particles present and not their type". 
Which statement(s) about the equilibrium constant, K c, is/are true?i. Kc changes as the concentration of a reactant changesii. Kc changes if the reaction is immersed in a hot water bathiii. Kc changes if a catalyst is added to the reactiona. i onlyb. ii onlyc. iii onlyd. i and iie. ii and iii
The reaction4PH3(g) ⇌ P4(s) + 6H2(g)is endothermic. In order to maximize the amount of H 2 present at equilibrium,a) raise the temperature and increase the volume.b) lower the temperature and raise the pressure with an inert gas.c) raise the temperature and decrease the volume.d) lower the temperature and increase the volume.e) lower the temperature and decrease the volume.
Consider the following system at equilibrium. 2CO(g) + O2(g) ⇌ 2CO2(g) How will increasing the concentration of CO shift the equilibrium? a) to the right b) to the left c) no effect  
Consider the following reaction at equilibrium. What effect will adding some C have on the system?CO2(g) + C(graphite) ⇌ 2CO(g)A)  No effect will be observed since C is not included in the equilibrium expression.B) The equilibrium constant will decrease.C) The reaction will shift to the left in the direction of reactants.D) The equilibrium constant will increase.E) The reaction will shift to the right in the direction of products.
The reaction2NaHCO3(s) ⇌ Na2CO3(s) + H2O(g) + CO2(g)is endothermic. What would you do in order to maximize the yield of Na 2CO3(s)?a) Lower the temperature and increase the volume of the container.b) Raise the temperature and add CO2(g) and H2O(g).c) Lower the temperature and decrease the volume of the container.d) Add CO2(g) and H2O(g) and increase the volume of the container.e) Increase the volume of the container and raise the temperature.
The reactionCO(g) + 2H2(g) ⇌ CH3OH(g)is endothermic. Which of the following statements about this reaction is true?a) Raising the temperature will cause the equilibrium constant to increase.b) Lowering the temperature will cause the rate of the forward reaction to increase.c) Raising the temperature will cause the equilibrium constant to decrease.d) Lowering the temperature will cause the equilibrium constant to increase.e) Raising the temperature will cause the rate of the back reaction to decrease.
Consider the following reaction at equilibrium. What effect will decreasing the temperature have on the system? More than one choice may be correct. CO2(g) + 2 H2O(l) ⇋ CH4(g) + 2 O2(g)    ΔH° = +890 kJA) The reaction will shift to the left in the direction of reactants.B) The equilibrium constant will decrease. C) The equilibrium constant will increase.D) The reaction will shift to the right in the direction of products.E) No effect will be observed.
 The next three questions refer to the following exothermic gas phase process at equilibrium:2SO2(g) + O2(g) ⟺ 2SO3(g) Predict  what will happen when the temperature is raised.a) equilibrium will shift to the left and more O 2 will be formedb) equilibrium will shift to the right and more SO 3 will be formedc) there will be no change in the position of the equilibriumd) more information is needed to answer this questione) this is an exothermic reaction so it is not possible to raise the temperature.Predict what will happen when more O 2 is added.a) equilibrium will shift to the left and more O 2 will be formedb) equilibrium will shift to the right and more SO 3 will be formedc) there will be no change in the position of the equilibriumd) more information is needed to answer this questione) it is not possible to add more O 2 to this reactionPredict what will happen when some Ar gas is introduced at constant volume (pressure increased).a) equilibrium will shift to the left and more O 2 will be formedb) equilibrium will shift to the right and more SO 3 will be formedc) there will be no change in the position of the equilibriumd) more information is needed to answer this questione) it is not possible to add AR gas to this equilibrum
For the below reaction, which of the statements will shift the equilibrium to the left (make more reactants).PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)                 ΔH= 105kJ(i) Cl2 (g) is removed(ii) the temperature is decreased(iii) the volume of the reaction system is increased(iv) PCl3(g) is added.A) (i) and (ii)B) (i) and (iv)C) (i) and (iii)D) (ii) and (iv)E) (iii) and (iv)
NH4Cl(s) ⇌ NH3(g) + HCl(g) is endothermic. How many of the following would cause an increase in the equilibrium pressure of HCI(g)?  An increase in temperature Removal of some NH4Cl A decrease in volume  Removal of some NH3(g)  a) none b) 1 c) 2 d) 3 e) 4  
Consider the reaction: 2SO2 (g) + O2 (g) ⟺ 2SO3 (g) ΔH = -198.2 kJ/mol. What would be the effect on the reaction if we were to:a. decrease the temperature b. decrease the pressure c . add a catalyst
CaCO3 decomposes by the following reaction in a closed container with excess CaCO3 remaining once the reaction reaches equilibrium. Which change will allow more quantity of CaCO3 to decompose?CaCO3 (s) ⇌ CaO (s) + CO2 (g)A. Adding more CaCO3 (s) to the containerB. Removing CaO (s) from the containerC. Allowing CO2 (g) to escape the containerD. Decreasing the volume of the container
The process, 2 NH 3(g) ----> heat + N 2(g) + 3 H 2(g), is at equilibrium at a given temperature.  Which of the following changes will change the equilibrium constant for the process?    A)    Adding more NH 3 to the system, with the volume held constant.    B)    Increasing the pressure by reducing the volume of the system.    C)    Adding an effective catalyst for the process.    D)    Raising the temperature of the system.    E)    Adding some neon to the system.
Consider the following reaction at equilibrium. What effect will increasing the volume of the reaction mixture have on the system?2 H2S(g) + 3 O2(g) ⇌ 2 H2O(g) + 2 SO2(g)A) The reaction will shift to the right in the direction of products.B) No effect will be observed.C) The reaction will shift to the left in the direction of reactants.D) The equilibrium constant will decrease.E) The equilibrium constant will increase.
PbCl2 (s) ↔ Pb2+ (aq) + 2 Cl - (aq) (This process is ENDOTHERMIC)1. If we add NaCl to the solution.2. If we raise the temperature by adding heat to the solution.3. If we add more solid PbCl 2.4. If we add pure water to dilute the solution.
Which factors will affect both the position of equilibrium and the value of the equilibrium constant for this reaction?N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)            ΔH = -92 kJa) increasing the volume of the containerb) adding more nitrogen gasc) removing ammonia gasd) lowering the temperature  
The reversible reaction2 H2 (g) + CO (g) ⇋ CH3OH (g) + heatis carried out by mixing carbon monoxide and hydrogen gases in a closed vessel under high pressure with a suitable catalyst. After equilibrium is established at high temperature and pressure, all three substances are present. If the pressure on the system is lowered, with the temperature kept constant, what will be the result?a) The amount of CH3OH will be increased.b) The amount of CH3OH will be decreased.c) The amount of each substance will be unchanged.d) The amount of each substance will be increaed. 
Consider this reaction, carried out at constant volume.2 SO2 (g) + O2 (g) ⇌ 2 SO3 (g)           Δ H = -198kJThe concentration of O2 (g) at equilibrium increases ifa) SO2 is added to the system.b) SO3 is added to the system.c) the temperature of the system is lowered.d) an inert gas is added to the system.  
Which one of the following changes has  no effect on the position of the equilibrium?A) concentration change                     B) volume change            C) pressure changeD) temperature changeE) addition of a catalyst
The position of equilibrium would not be appreciably affected by changes in the volume of the container for
Consider this reaction, carried out at constant temperature and volume.2 SO2 (g) + O2 (g) ⇌ 2 SO3 (g) What is the effect of removing some SO3 from  system initially at equilibrium?a) The concentration of SO2 decreases more than the concentration of O 2.b) The concentration of SO2 increases more than the concentration of O 2.c) The concentration of SO2 and O2 remain the same.d) The concentration of SO2 and O2 decrease equally.
A solution of potassium hydroxide is in equilibrium with undissolved solute at 45°C. What will happen if the temperature is raised to 50°C?(ΔHsoln = -57.6 kJ/mol)A) The mass of dissolved KOH will increase.B) The mass of dissolved KOH will decrease.C) The mass of dissolved KOH will be unchanged.D) The mass of water in the solution will increase.E) More information is needed in order to make a reliable prediction. 
Consider the following system at equilibrium:  CH 4(g) + 2H 2O(g) ⇌  CO 2(g) + 4H 2(g)        What change will cause the equilibrium to shift to form more CO  2?    A) increase [H 2]                         D) decrease [CH   4]    B) decrease [H 2O]                    E) decrease [H 2]    C) decrease the volume of the reaction vessel
Consider this reaction.heat + CaSO3 (s) ⇌ CaO (s) + SO2 (g)What change will cause an increase in the pressure of SO 2 (g) when equilibrium is re-established?a) increasing the reaction temperatureb) decreasing the volume of the container.c) adding some more CaSO3d) removing some of the CaO(s) 
In which reaction would an increase in pressure at constant temperature have no effect on the relative amounts of the subtances present in the equilibrium mixture? All subtances are gases.a) 2 NO + O2  ⇌  2 NO2 + heatb) heat + N2 + O2 ⇌ 2 NOc) N2 + 3 H2 ⇌ 2 NH3 + heatd) 2 CO + O2 ⇌ 2 CO2 + heat 
Consider the following system at equilibrium: NO(g) + SO 3(g) ⇌  NO 2(g) + SO 2(g)        What change will cause the equilibrium to shift to form more NO?    A) increase [SO 3]                    D) decrease [NO 2]    B) decrease [SO 2]                    E) decrease [SO 3]    C) decrease the volume of the reaction vessel  
The numerical value of the equilibrium constant for any chemical change is affected by changing thea) nature of the catalyst.b) concentration of the products.c) the pressure.d) the temperature,
Solid carbon and gaseous carbon dioxide are placed in a closed vessel and allowed to come to equilibrium at a high temperature according to this equation.heat + C (s) + CO2 (g) ⇌ 2 CO (g)If the pressure on the system is increased and the temperature kept constant, what will be the result?a) The amount of CO will increase and that of C and CO 2 will decrease.b) The amount of CO will decrease and that of C and CO 2 will increase.c) The amount of each of the three subtances will increase.d) The amount of each of the three substances will decrease.
Consider the following system at equilibrium.2CO (g) + O2 (g) ⇌ 2CO2(g)How will increasing the concentration of CO 2 shift the equilibrium?a) to the rightb) to the leftc) no effect
Consider the combustion of glucose:C6H12O6 (s) + 6 O2 (g) ↔ 6 CO2 (g) + 6 H2O (g)     ΔH = −2,800 kJ/molWhich condition would result in the production of additional water vapor?I) adding more carbon dioxideII) performing the reaction in a hotter environmentIII) decreasing the pressure of the system 1. II and III2. I, II and III3. I and II4. I and III5. III only6. I only7. II only
Which direction would the following endothermic reaction shift - (to the left (←) or to the right (→) or no change (0) after each of the following disturbances.2 NOBr (g) ⇌ 2 NO (g) + Br (g)a) add more NO(g)b) increase temperaturec) add more NOBr(g)d) increase volume
Consider the reactionNi (s) + 4 CO (g) → Ni(CO)4 (g).At 30°C and PCO = 1 atm, Ni reacts with CO (g) to form Ni(CO) 4 (g). At 200°C, Ni(CO)4 (g) decomposes to Ni (s) and CO (g). This means1. the forward reaction is endothermic.2. adding an inert gas like argon favors the forward reaction.3. the activation energy for the forward reaction is greater than for the reverse reaction.4. a decrease in pressure favors the forward reaction.5. K at 30°C is greater than K at 200°C.
For the equation,2 H2 (g) + X2 (g) ⇌ 2 H2X (g) + energyi) Write the equilibrium constant expression.  ii) Addition of argon to the above equilibrium a) will cause [H2] to decrease.                      b) will cause [X2] to increase.c) will cause [H2X] to increase.                     d) will have no effect.e) cannot possibly be carried out.  iii) Increasing the pressure by decreasing the volume will cause a) the reaction to occur to produce H2X.b) the reaction to occur to produce H2 and X2.c) the reaction to occur to produce H2 but no more X2.d) no reaction to occur. e) X2 to dissociate.
In which of these gas-phase equilibria is the yield of products increased by increasing the total pressure on the reaction mixture?A) CO(g) + H2O(g) ⇋ CO2(g) + H2(g)B) 2NO(g) + Cl2(g) ⇋ 2NOCl(g)C) 2SO3(g) ⇋ 2SO2(g) + O2(g)D) PCl5(g) ⇋ PCl3(g) + Cl2(g)E) 2H2O2(g) ⇋ 2H2O(g) + O2(g) 
Consider the following system at equilibrium.H2 (g) + I2 (g) ⇌ 2 HI (g) + heatWhich response includes all the following that will shift the equilibrium to the left, and no others?I) increasing the temperatureII) decreasing the temperatureIII) increasing the pressureIV) decreasing the pressureV) removing some HIVI) adding some HIVII) removing some I2VIII) adding some I21. II, IV, VII, and VIII only2. I, VI, and VII only3. I, III, V, and VII only4. II, V, and VIII only5. II only
Suppose the exothermic reaction2 SO2 (g) + O2 (g) ⇌ 2 SO3 (g)comes to equilibrium. Then we increase the temperature and decrease the total pressure simultaneously. What will be the effect on the net amount of SO3(g)?1. It decreases.2. It does not change.3. It increases.4. It may either increase, decrease, or remain the same, depending on the numerical value of the equilibrium constant.5. It may either increase, decrease, or remain the same, depending on the sizes of the temperature and pressure changes.
Consider the following reaction at equilibrium:2 CO2 (g) ⇌ 2 CO (g) + O2 (g)           ΔH° = -514 kJHow can the yield of CO (g) be maximized?a) at high temperature and high pressureb) at high temperature and low pressurec) at low temperature and low pressured) at low temperature and high pressuree) in the presence of solid carbon
Which factors will affect both the position of equilibrium and the value of the equilibrium constantfor this reaction?           N2(g) + 3H2(g) 2NH3(g)                                                                 ∆H = –92kJ A. Increasing the volume of the containerB. Adding more nitrogen gasC. Removing ammonia gasD. Lowering the temperature
Coal, which is primarily carbon, can be converted to natural gas, primarily CH 4, by the exothermic reaction:C(s) + 2H2(g) ⇌ CH4(g)Which change will favor CH4 at equilibrium?a. adding more C to the reaction mixtureb. adding more H2 to the reaction mixturec. raising the temperature of the reaction mixtured. lowering the volume of the reaction mixturee. adding a catalyst to the reaction mixturef. adding neon gas to the reaction mixture
The reaction for the formation of ammonia by direct combination is:      N2(g) + 3H2(g) ⇌ 2NH3(g)                                                                    ∆H = –92kJ Which operation will increase the yield of ammonia in the equilibrium mixture? A. Doubling the concentration of hydrogenB. Reducing the total pressureC. Raising the temperatureD. Increasing the reaction timeE. Adding a catalyst
Which of the following equilibria will shift to the left in response to a decrease in volume?a) H2 (g) + Cl2 (g) ⇌ 2 HCl (g)b) 2 SO3 (g) ⇌  2 SO2 (g) + O2 (g)c) N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)d) 4 Fe (s) + 3 O2 (g) ⇌  2 Fe2O3 (s)e) 2 HI (g) ⇌ H2 (g) + I2 (g) 
For reversible reactions at equilibrium, a rise in temperature will: a) decrease the rates of reactions               b) favor the endothermic reaction c) have no effect upon the equilibrium         d) cause the evolution of more heat
When equilibrium has been reached in the reaction: AE + CD ⇌ CE + AD + xkJ in which all substances are in solution, A. Adding AE will increase the concentration of CE but not ADB. Adding CD will increase the concentration of both AE and ADC. Heating will increase the concentration of both AE and CED. Escape of some AD by volatilization will increase the concentration of CEE. Doubling the pressure will increase the concentration of CE
Which one of the following will change the value of an equilibrium constant?a) changing temperatureb) adding other substances that do not react with any of the species involved in the equilibriumc) varying the initial concentrations of reactantsd) varying the initial concentrations of productse) all of these
Given the reaction: 2 X (g) + Y (g)   ⇌    2 Z (g)                      ∆H = – 335kJ Which combination of pressure and temperature gives the highest yield of Z at equilibrium? A. 1000 atm and 500 CB. 500 atm and 500 CC. 1000 atm and 100 CD. 500 atm and 100 CE. Catalyst, 500 atm and 100 C
Consider this reaction, carried out at constant volume:  2SO2(g) + O2(g)    2SO3(g)          ∆H=  –198kJ The concentration of oxygen gas at equilibrium increases if: A. SO2 is added to the system.B. SO3 is added to the systemC. The temperature of the system is lowered.D. A minimal amount of inert gas is added to the system
Consider the following reaction at equilibrium:2 NH3 (g) ⇌ N2 (g) + 3 H2 (g)                 ΔH° = + 92.4 kJIncreasing the temperature to the system at equilibrium will ___________________.a) derease the concentration of NH 3 (g) at equilibrium. b) decrease the concentration of H 2 (g) at equilibrium. c) cause no change to the system. d) cause the reaction to shift to the left.e) remove all of the H 2 (g).
Consider the following reaction at equilibrium:2 NH3 (g) ⇌ N2 (g) + 3 H2 (g)          ΔH° = + 92.4 kJDecreasing the volume of the system at equilibrium will ______________________.a) decrease the concentration of NH 3 (g) at equilibrium.b) decrease the concentration of H 2 (g) at equilibrium.c) cause no change in the system.d) cause the reaction to shift to the left.e) remove all of the H 2 (g).
Consider the following reaction at equilibrium:2 NH3 (g) ⇌ N2 (g) + 3 H2 (g)      ΔH° = +92.4 kJAdding N2 (g) to the system at equilibrium will ________________.a) decreases the concentration of NH 3 (g) at equilibrium. b) decrease the concentration of H 2 (g) at equilibrium. c) increase the value of the equilibrium constant.d) cause the reaction to shift to the right.e) Remove all of the H 2 (g).
The following reaction is exothermic:Fe3+ (g) + Br - (g) ⇌ FeBr2+ (g)How will the equilibrium concentration of FeBr 2+ change if the partial pressure of Fe3+ is decreased?
One of the most important industrial sources of ethanol is the reaction of steam with ethane derived from crude oil. The reaction is represented by the following thermochemical equation:
Consider the following reaction at equilibrium:2KClO3(s) ⇌ 2KCl(s) + 3O2(g)The following changes are made in the conditions:1) Oxygen is added to the mixture2) KCl is added to the mixtureHow would each change influence the reaction?           1                                  2A) No Change                 Shifts RightB) Shifts Right                 Shifts RightC) Shifts Right                 No ChangeD) Shifts Left                    Shifts RightE) Shifts Left                     No Change
Consider the following exothermic reaction:C2H4(g) + Cl2(g) ⇌ C2H4Cl2(g)If you were a chemist trying to maximize the amount of C2H4Cl2 produced, which of the following might you try? Assume that the reaction mixture reaches equilibrium.A) condense C2H4Cl2 as a pure liquid from the reaction mixtureB) decrease the total pressureC) increase the total pressureD) raise the temperatureE) both A and C
Consider the following reaction at equilibrium. What effect will raising the CO2 pressure have on the system?CaO(s) + CO2(g) ⇌ CaCO3(s)A) No effect will be observed since CO 2 is not included in the equilibrium expression.B) The equilibrium constant will decrease.C) The reaction will shift to the left in the direction of reactants.D) The equilibrium constant will increase.E) The reaction will shift to the right in the direction of products. 
What will be the effect of increasing the temperature of reactants that are known to undergo an endothermic reaction?(A) Both the rate of reaction and the value of the equilibrium constant increase.(B) The rate of reaction increases and the value of the equilibrium constant decreases.(C) The rate of reaction decreases and the value of the equilibrium constant increases.(D) The rate of reaction increases and the value of the equilibrium constant is unchanged.
Consider the following reaction at equilibrium: A (g) ⟺ 2B (g)From the data shown below, determine if the forward reaction is endothermic or exothermic - be sure to explain how you came to that conclusion.
The reaction for the synthesis of ammonia N2(g) + 3H2(g) ⇌ 2NH3(g) is exothermic. To obtain the greatest yield of NH3, this reaction should be carried out at1. low temperature, low pressure.2. low temperature, high pressure.3. high temperature, low pressure.4. high temperature, high pressure.5. any temperature, any pressure
Consider the gas-phase reaction:2 CO (g)  +  O2 (g) ⇌ 2 CO2 (g)Predict the shift in the equilibrium position when argon gas is added to the mixture:a. At constant pressure   b. At constant volume
Consider this reaction, carried out at constant temperature and volume.PCl5(g) ⇌ PCl3(g) + Cl2(g)How can the position of equilibrium for this reaction be shifted to the right?(A) addition of a catalyst(B) removal of Cl2(C) addition of an inert gas at constant volume(D) removal of PCl5
Baking soda (sodium bicarbonate) undergoes spontaneous decomposition at high enough temperatures to produce the following equation:2 NaHCO3 (s)  ⇌ Na2CO3 (s)  +  CO2 (g)  +  H2O (g)Would we obtain more CO2 and H2O by adding extra baking soda to the reaction mixture in:a. A closed vessel or systemb. An open vessel or system 
Consider the endothermic reaction: CaCO3 (s) + 2 H+ (aq) ↔ Ca2+ (aq) + CO2 (g) +H2O (l). A vessel contains all of the substances at equilibrium. Which of the following changes will lead to an increase in BOTH K and pH?1. add water2. add CO23. add strong acid4. add CaCO35. increase Temperature
Coal, which is primarily carbon, can be converted to natural gas, CH4, by the following reaction: C (s) + 2 H2 (g) ⇌ CH4 (g)   ΔHo= -74.6kJWhich of the following changes would increase the concentration of CH4?i. adding more Cii. decreasing the temperatureiii increasing the volumeA. i onlyB. ii onlyC. iii onlyD. i and ii   
For the exothermic reaction: 4 NH 3 (g) + 7 O 2 (g) → 4 NO 2 (g) + 6 H 2O (g), which change will increase the quantity of NO 2 in the mixture?A) increasing temperatureB) decreasing container volumeC) adding Ne(g)D) adding H2O(g) 
The following data was collected for the following reaction at equilibrium.A (s)  + 2 B  (g)  ⇌ 3 C (g) +  D (g)At 55oC, K is 3.9 x 10 -3 and at 100oC K is 8.5 x 10 -5. Which of the following statements is true?The reaction is exothermic.The reaction is endothermic.The enthalpy change, ΔH, is equal to zero.Not enough information is given 
Which change in the system will drive equilibrium to the left in the reaction below?N 2O 5(g) ⇌ NO 2(g) + NO 3(g)        A) decrease the amount of NO 3                B) increase the pressureC) increase the amount of N 2O 5               D) increase the volume
A solution of sodium acetate in water is observed to become more alkaline as the temperature is raised. Which conclusion can be drawn? This is the equation for the reaction. Na+(aq) + C2H3O2–(aq) + H2O(l) ⇌ HC2H3O2(aq) + Na+(aq) + OH–(aq)(A) The forward reaction proceeds with evolution of heat.(B) The forward reaction proceeds with absorption of heat. (C) Acetic acid is less soluble in hot water than in cold water.(D) at higher temperatures, Na+(aq) + OH–(aq) → NaOH (aq) will occur. 
Which of the following changes to a system at equilibrium will force the reaction to shift towards the products6 A (s) + 3 B2 (g) ⇌ 4 AB (g) + A2B2 (g)        ΔH = -182.7 kJa. adding some Ab. adding some A2B2c. decreasing the total pressured. increasing the temperaturee. addition of a catalyst 
What property of a reaction can we use to predict the effect of a change in temperature on the value of an equilibrium constant?
The synthesis of ammonia gas from nitrogen gas and hydrogen gas represents a classic case in which a knowledge of kinetics and equilibrium was used to make a desired chemical reaction economically feasible. Explain how each of the following conditions helps to maximize the yield of ammonia.a. running the reaction at an elevated temperature
A necessary step in the manufacture of sulfuric acid is the formation of sulfur trioxide, SO3, from sulfur dioxide, SO2, and oxygen, O2, shown here. At high temperatures, the rate of formation of SO3 is higher, but the equilibrium amount (concentration or partial pressure) of SO 3 is lower than it would be at lower temperatures. 2SO2(g) + O2(g) ⟶ 2SO3(g) (a) Does the equilibrium constant for the reaction increase, decrease, or remain about the same as the temperature increases?
A necessary step in the manufacture of sulfuric acid is the formation of sulfur trioxide, SO3, from sulfur dioxide, SO2, and oxygen, O2, shown here. At high temperatures, the rate of formation of SO3 is higher, but the equilibrium amount (concentration or partial pressure) of SO 3 is lower than it would be at lower temperatures. 2SO2(g) + O2(g) ⟶ 2SO3(g)(b) Is the reaction endothermic or exothermic?
How will an increase in temperature affect from the following equilibria? How will a decrease in the volume of the reaction vessel affect each?(a) 2NH3(g) ⇌ N2(g) + 3H2(g)             ΔH = 92 kJ
How will an increase in temperature affect from the following equilibria? How will a decrease in the volume of the reaction vessel affect each?(b) N2(g) + O2(g) ⇌ 2NO(g)    ΔH = 181 kJ
What additional information do we need to answer the following question: How is the equilibrium of solid silverbromide with a saturated solution of its ions affected when the temperature is raised?
How will an increase in temperature affect from the following equilibria? How will a decrease in the volume of the reaction vessel affect each?(c) 2O3(g) ⇌ 3O2(g)          ΔH = −285 kJ
How will an increase in temperature affect from the following equilibria? How will a decrease in the volume of the reaction vessel affect each?(d) CaO(s) + CO2(g) ⇌ CaCO3(s)            ΔH = −176 kJ
How will an increase in temperature affect from the following equilibria? How will a decrease in the volume of the reaction vessel affect each?(a) 2H2 O(g) ⇌ 2H2(g) + O2(g)                     ΔH = 484 kJ
How will an increase in temperature affect from the following equilibria? How will a decrease in the volume of the reaction vessel affect each?(b) N2(g) + 3H2(g) ⇌ 2NH3(g)                       ΔH = −92.2 kJ
How will an increase in temperature affect from the following equilibria? How will a decrease in the volume of the reaction vessel affect each?(c) 2Br(g) ⇌ Br2(g)                     ΔH = −224 kJ
How will an increase in temperature affect from the following equilibria? How will a decrease in the volume of the reaction vessel affect each?(d) H2(g) + I2(s) ⇌ 2HI(g)                                  ΔH = 53 kJ
The following reaction is exothermic: 2SO2(g) + O2(g) ⇌ 2SO3(g). What is the effect of increasing the temperature of the reaction mixture?
The following question is taken from a Chemistry Advanced Placement Examination and is used with the permission of the Educational Testing Service.Solve the following problem:MgF2(s) ⇌ Mg2+(aq) + 2F−(aq)In a saturated solution of MgF2 at 18°C, the concentration of Mg2+ is 1.21 × 10–3 M. The equilibrium isrepresented by the preceding equation.(d) At 27°C the concentration of Mg2+ in a saturated solution of MgF2 is 1.17 × 10–3 M. Is the dissolving of MgF2 in water an endothermic or an exothermic process? Give an explanation to support your conclusion.
The following reaction is exothermic: 2SO2(g) + O2(g) ⇌ 2SO3(g). What is the effect of decreasing the temperature of the reaction mixture?
The “filmstrip” represents five molecular scenes of a gaseous mixture as it reaches equilibrium over time:X is purple and Y is orange: X2(g) + Y2(g) ⇌ 2XY(g). (e) If ΔH°rxn < 0, which scene, if any, best represents the mixture at a higher temperature?  Explain. 
True or false: When the temperature of an exothermic reaction increases, the rate constant of the forward reaction decreases, which leads to a decrease in the equilibrium constant, Kc.
Predict the effect of increasing the temperature on the amount(s) of product(s) in the following reaction: (a) CO(g) + 2H2(g) ⇌ CH3OH(g)  ΔH°rxn = −90.7 kJ 
Predict the effect of increasing the temperature on the amount(s) of product(s) in the following reaction: (b) C(s) + H2O(g) ⇌ CO(g) + H2(g)  ΔH°rxn = 131 kJ 
An important reaction in the commercial production of hydrogen isCO(g) + H2O(g) ⇌ H2(g) + CO2(g)How will this system at equilibrium shift in each of the following cases?d. The temperature is increased (the reaction is exothermic).
Predict the effect of increasing the temperature on the amount(s) of product(s) in the following reaction: (c) 2NO2(g) ⇌ 2NO(g) + O2(g) (endothermic) 
Predict the effect of increasing the temperature on the amount(s) of product(s) in the following reaction: (d) 2C(s) + O2(g) ⇌ 2CO(g) (exothermic)
What will happen to the number of moles of SO 3 in equilibrium with SO2 and O2 in the reaction2SO3(g) ⇌ 2SO2(g) + O2(g)in each of the following cases?d. The temperature is decreased (the reaction is endothermic).
Predict the effect of decreasing the temperature on the amount(s) of reactant(s) in the following reaction: (a) C2H2(g) + H2O(g) ⇌ CH3CHO(g)  ΔH°rxn = −151 kJ 
Predict the effect of decreasing the temperature on the amount(s) of reactant(s) in the following reaction: (b) CH3CH2OH(l) + O2(g) ⇌ CH3CO2H(l) + H2O(g) ΔH°rxn = −451 kJ
In which direction will the position of the equilibrium2HI(g) ⇌ H2(g) + I2(g)be shifted for each of the following changes?f. The temperature is decreased (the reaction is exothermic).
Predict the effect of decreasing the temperature on the amount(s) of reactant(s) in the following reaction: (c) 2C2H4(g) + O2(g) ⇌ 2CH3CHO(g) (exothermic) 
Hydrogen for use in ammonia production is produced by the reactionWhat will happen to a reaction mixture at equilibrium ifb. the temperature is increased (the reaction is endothermic)?
Predict the effect of decreasing the temperature on the amount(s) of reactant(s) in the following reaction: (d) N2O4(g) ⇌ 2NO2(g) (endothermic)
Old-fashioned “smelling salts” consist of ammonium carbonate, (NH 4)2CO3. The reaction for the decomposition of ammonium carbonate(NH4)2CO3(s) ⇌ 2NH3(g) + CO2(g) + H2O(g)is endothermic. Would the smell of ammonia increase or decrease as the temperature is increased?
Consider the following reaction at equilibrium: 2CO2 (g) <---> 2CO (g) + O2 (g) ΔH° = -514 kJ Le Chatelier's principle predicts that an increase in temperature will __________. a. increase the partial pressure of O2 (g) b. decrease the value of the equilibrium constant c. increase the partial pressure of CO d. decrease the partial pressure of CO2 (g) e. increase the value of the equilibrium constant
The following reaction is endothermic: C(s) + CO2(g) ⇌ 2 CO(g)Predict the effect (shift right, shift left, or no effect) of increasing and decreasing the reaction temperature. How does the value of the equilibrium constant depend on temperature?
The following reaction is endothermic: C(s) + CO2(g) ⇌ 2 CO(g)Predict the effect (shift right, shift left, or no effect) of increasing the reaction temperature.
The following reaction is endothermic: C(s) + CO2(g) ⇌ 2 CO(g)Predict the effect (shift right, shift left, or no effect) of decreasing the reaction temperature.
The following reaction is exothermic: C6H12O6(s) + 6 O2(g) ⇌ 6 CO2(g) + 6 H2O(g)Predict the effect (shift right, shift left, or no effect) of increasing and decreasing the reaction temperature.How does the value of the equilibrium constant depend on temperature?
The following reaction is exothermic: C6H12O6(s) + 6 O2(g) ⇌ 6 CO2(g) + 6 H2O(g)Predict the effect (shift right, shift left, or no effect) of increasing the reaction temperature.
The following reaction is exothermic: C6H12O6(s) + 6 O2(g) ⇌ 6 CO2(g) + 6 H2O(g)Predict the effect (shift right, shift left, or no effect) of decreasing the reaction temperature.
What is the effect of adding helium gas (at constant volume) to an equilibrium mixture of the reaction: CO(g) + Cl2(g) ⇌ COCl2(g)
Chromium(VI) forms two different oxyanions, the orange dichromate ion, Cr 2O72-, and the yellow chromate ion, CrO42-. (See the following photos.) The equilibrium reaction between the two ions isCr2O7 2-(aq) + H2O(l) ⇌ 2CrO4 2-(aq) + 2H+(aq)Explain why orange dichromate solutions turn yellow when sodium hydroxide is added.
The synthesis of ammonia gas from nitrogen gas and hydrogen gas represents a classic case in which a knowledge of kinetics and equilibrium was used to make a desired chemical reaction economically feasible. Explain how each of the following conditions helps to maximize the yield of ammonia.c. using a catalyst 
Consider this equilibrium system: CO(g) + Fe3O4(s) ⇌ CO2(g) + 3FeO(s) How does the equilibrium position shift as a result of the following disturbance? (c) Additional Fe3O4(s) is added to the system.
Sodium bicarbonate undergoes thermal decomposition according to the reaction: 2NaHCO3(s) ⇌ Na2CO3(s) + CO2(g) + H2O(g) How does the equilibrium position shift as a result of the following disturbance? (a) 0.20 atm of argon gas is added.
Sodium bicarbonate undergoes thermal decomposition according to the reaction: 2NaHCO3(s) ⇌ Na2CO3(s) + CO2(g) + H2O(g) How does the equilibrium position shift as a result of the following disturbance? (b) NaHCO3(s) is added. 
Water gas, a mixture of H2 and CO, is an important industrial fuel produced by the reaction of steam with red hot coke, essentially pure carbon:  C(s) + H2O(g) ⇌ CO(g) + H2(g)(b) What will happen to the concentration of each reactant and product at equilibrium if more C is added?
Suppose the reaction systemUO2(s) + 4HF(g) ⇌ UF4(g) + 2H2O(g)has already reached equilibrium. Predict the effect that each of the following changes will have on the equilibrium position. Tell whether the equilibrium will shift to the right, will shift to the left, or will not be affected.a. Additional UO2(s) is added to the system.
An important reaction in the commercial production of hydrogen isCO(g) + H2O(g) ⇌ H2(g) + CO2(g)How will this system at equilibrium shift in each of the following cases?c. In a rigid reaction container, the pressure is increased by adding helium gas.
H2 and I2 are combined in a flask and allowed to react according to the following reaction: H2(g) + I2(g) ⇌ 2 HI(g)Examine the figures (sequential in time) and answer the following questions.How would the series of figures change in the presence of a catalyst?
H2 and I2 are combined in a flask and allowed to react according to the following reaction: H2(g) + I2(g) ⇌ 2 HI(g)Examine the figures (sequential in time) and answer the following questions.Would the final figure (vi) have different amounts of reactants and products in the presence of a catalyst?
In which direction will the position of the equilibrium2HI(g) ⇌ H2(g) + I2(g)be shifted for each of the following changes?d. In a rigid reaction container, some Ar( g) is added.
Hydrogen for use in ammonia production is produced by the reactionWhat will happen to a reaction mixture at equilibrium ifc. an inert gas is added to a rigid reaction container?
Additional solid silver sulfate, a slightly soluble solid, is added to a solution of silver ion and sulfate ion at equilibrium with solid silver sulfate.2Ag+(aq) + SO4 2−(aq) ⇌ Ag2 SO4(s)Which of the following will occur?(a) Ag+ or SO4 2− concentrations will not change.(b) The added silver sulfate will dissolve.(c) Additional silver sulfate will form and precipitate from solution as Ag+ ions and SO4 2− ions combine.(d) The Ag+ ion concentration will increase and the SO 4 2− ion concentration will decrease.
The oxidation of SO2 is the key step in H2SO4 production:   SO2(g) + ½O2(g) ⇌ SO3(g)  ΔH°rxn = −99.2 kJ(c) Why is catalysis used for this reaction?
Consider the following reaction at equilibrium: 2 KClO3(s) ⇌ 2 KCl(s) + 3 O2(g)Predict whether the reaction will shift left, shift right, or remain unchanged if KCl is added to the reaction mixture.
Consider the following reaction at equilibrium: 2 KClO3(s) ⇌ 2 KCl(s) + 3 O2(g)Predict whether the reaction will shift left, shift right, or remain unchanged if KClO3 is added to the reaction mixture.
Consider the following reaction at equilibrium: C(s) + H2O(g) ⇌ CO(g) + H2(g)Predict whether the reaction will shift left, shift right, or remain unchanged upon each of the following disturbances.a. C is added to the reaction mixture.b. H2O is condensed and removed from the reaction mixture.c. CO is added to the reaction mixture.d. H2 is removed from the reaction mixture.
Why are there no changes specified for Ni below? What property of Ni does change?change in pressure:Ni(s) + 4CO(g) ⇌ Ni(CO)4(g)              4x             ___         0.40 atm       ___
Why are there no changes specified for NH4HS below? What property of NH4HS does change?NH4HS(s) ⇌ NH3(g)   +   H2S(g)   ___               x                ___   ___           9.8×10−6 M   ___
Coal can be used to generate hydrogen gas (a potential fuel) by the following endothermic reaction:C(s) + H2O(g) ⇌ CO(g) + H2(g)If this reaction mixture is at equilibrium, predict whether each of the following will result in the formation of additional hydrogen gas, result in the formation of less hydrogen gas, or have no effect on the quantity of hydrogen gas.a. adding more C to the reaction mixtureb. adding more H2O to the reaction mixturec. raising the temperature of the reaction mixtured. increasing the volume of the reaction mixturee. adding a catalyst to the reaction mixturef. adding an inert gas to the reaction mixture
Consider the simple one-step reaction: A(g) ⇌ B(g)Since the reaction occurs in a single step, the forward reaction has a rate of kfor[A] and the reverse reaction has a rate of krev[B].What happens to the rate of the forward reaction when we increase the concentration of A?
Novelty devices for predicting rain contain cobalt(II) chloride and are based on the following equilibrium:CoCl2(s) + 6H2O(g) ⇌ CoCl2•6H2O(s)Purple                                 PinkWhat color will such an indicator be if rain is imminent?
Consider the reactionFe3+(aq) + SCN -(aq) ⇌ FeSCN 2+(aq)How will the equilibrium position shift ifb. AgNO3(aq) is added? (AgSCN is insoluble.)
Consider the reactionFe3+(aq) + SCN -(aq) ⇌ FeSCN 2+(aq)How will the equilibrium position shift ifc. NaOH(aq) is added? [Fe(OH)3 is insoluble.]
Consider the reactionFe3+(aq) + SCN -(aq) ⇌ FeSCN 2+(aq)How will the equilibrium position shift ifd. Fe(NO3)3(aq) is added?
Consider the following reaction at equilibrium: 2 BrNO(g) ⇌ 2 NO(g) + Br2(g)Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance.a. NO is added to the reaction mixture.b. BrNO is added to the reaction mixture.c. Br2 is removed from the reaction mixture.
What would happen to the color of the solution in part (b) from following Figure. if a small amount of NaOH were added and Fe(OH)3 precipitated? Explain your answer.Figure 13.8 (a) The test tube contains 0.1 M Fe3+. (b) Thiocyanate ion has been added to solution in (a), forming the red Fe(SCN)2+ ion. Fe3+(aq) + SCN−(aq) ⇌ Fe(SCN)2+(aq). (c) Silver nitrate has been added to the solution in (b), precipitating some of the SCN− as the white solid AgSCN. Ag+(aq) + SCN−(aq) ⇌ AgSCN(s). The decrease in the SCN− concentration shifts the first equilibrium in the solution to the left, decreasing the concentration (and lightening color) of the Fe(SCN)2+.
The synthesis of ammonia gas from nitrogen gas and hydrogen gas represents a classic case in which a knowledge of kinetics and equilibrium was used to make a desired chemical reaction economically feasible. Explain how each of the following conditions helps to maximize the yield of ammonia.b. removing the ammonia from the reaction mixture as it forms 
Hemoglobin (Hb) transport oxygen in the blood:HbH+(aq) + O2(aq) + H2O(l)⟶HbO2(aq) + H3O+(aq)In blood, [H3O+] is held nearly constant at 4×10 −8 M.(a) How does the equilibrium position change in the lungs?
Hemoglobin (Hb) transport oxygen in the blood:HbH+(aq) + O2(aq) + H2O(l)⟶HbO2(aq) + H3O+(aq)In blood, [H3O+] is held nearly constant at 4×10 −8 M.(b) How does it change in O 2-deficient cells?
Consider the following reaction in chemical equilibrium: 2 BrNO(g) ⇌ 2 NO(g) + Br2(g)2 m BrNO(g); ightleftharpoons;2 NO(g) +  Br_{2}(g)What is the effect of adding additional Br2(g) to the reaction mixture? What is the effect of adding additional BrNO(g)?
Hemoglobin (Hb) transport oxygen in the blood:HbH+(aq) + O2(aq) + H2O(l)⟶HbO2(aq) + H3O+(aq)In blood, [H3O+] is held nearly constant at 4×10 −8 M.(c) Excessive vomiting may lead to metabolic alkalosis, in which [H 3O+] in blood decreases. How does this condition affect the ability of Hb to transport O2?
Hemoglobin (Hb) transport oxygen in the blood:HbH+(aq) + O2(aq) + H2O(l)⟶HbO2(aq) + H3O+(aq)In blood, [H3O+] is held nearly constant at 4×10 −8 M.(d) Diabetes mellitus may lead to metabolic acidosis, in which [H 3O+] in blood increases. How does this condition affect the ability of Hb to transport O2?
Consider this equilibrium system: CO(g) + Fe3O4(s) ⇌ CO2(g) + 3FeO(s) How does the equilibrium position shift as a result of the following disturbance? (b) CO2 is removed by adding solid NaOH.
Water gas is a 1:1 mixture of carbon monoxide and hydrogen gas and is called water gas because it is formed from steam and hot carbon in the following reaction: H2O(g) + C(s) ⇌ H2(g) + CO(g). Methanol, a liquid fuel that could possibly replace gasoline, can be prepared from water gas and hydrogen at high temperature and pressure in the presence of a suitable catalyst.(a) Write the expression for the equilibrium constant (Kc) for the reversible reaction2H2(g) + CO(g) ⇌ CH3OH(g) ΔH = −90.2 kJ(b) What will happen to the concentrations of H2, CO, and CH3OH at equilibrium if more H2 is added?(c) What will happen to the concentrations of H2, CO, and CH3OH at equilibrium if CO is removed?(d) What will happen to the concentrations of H2, CO, and CH3OH at equilibrium if CH3OH is added?(e) What will happen to the concentrations of H2, CO, and CH3OH at equilibrium if the temperature of the system isincreased?(f) What will happen to the concentrations of H2, CO, and CH3OH at equilibrium if more catalyst is added?
Consider this equilibrium system: CO(g) + Fe3O4(s) ⇌ CO2(g) + 3FeO(s) How does the equilibrium position shift as a result of the following disturbance? (d) Dry ice is added at constant temperature.
In a 3.0-L vessel, the following equilibrium partial pressures are measured: N 2, 190 torr; H2, 317 torr; NH3, 1.00 × 103 torr. N2(g) + 3H2(g) ⇌ 2NH3(g)(a) How will the partial pressures of H2, N2, and NH3 change if H2 is removed from the system? Will they increase, decrease, or remain the same?
Sodium bicarbonate undergoes thermal decomposition according to the reaction: 2NaHCO3(s) ⇌ Na2CO3(s) + CO2(g) + H2O(g) How does the equilibrium position shift as a result of the following disturbance? (c) Mg(ClO4)2(s) is added as a drying agent to remove H 2O.
Sodium bicarbonate undergoes thermal decomposition according to the reaction: 2NaHCO3(s) ⇌ Na2CO3(s) + CO2(g) + H2O(g) How does the equilibrium position shift as a result of the following disturbance? (d) Dry ice is added at constant T.
Isopentyl alcohol reacts with pure acetic acid to form isopentyl acetate, the essence of banana oil:C5H11OH + CH3COOH ⥫⥬ CH3COOC5H11 + H2OA student adds a drying agent to remove H2O and thus increase the yield of banana oil. Is this approach reasonable?  Explain.
Nitrogen and oxygen react at high temperatures.(a) Write the expression for the equilibrium constant (Kc) for the reversible reactionN2(g) + O2(g) ⇌ 2NO(g) ΔH = 181 kJ(b) What will happen to the concentrations of N2, O2, and NO at equilibrium if more O2 is added?(c) What will happen to the concentrations of N2, O2, and NO at equilibrium if N2 is removed?(d) What will happen to the concentrations of N2, O2, and NO at equilibrium if NO is added?(e) What will happen to the concentrations of N2, O2, and NO at equilibrium if the pressure on the system is increased by reducing the volume of the reaction vessel?(f) What will happen to the concentrations of N2, O2, and NO at equilibrium if the temperature of the system is increased?(g) What will happen to the concentrations of N 2, O2, and NO at equilibrium if a catalyst is added?
Hemoglobin carries O2 from the lungs to tissue cells, where the O 2 is released. The protein is represented as Hb in its unoxygenated form and as Hb•O2 in its oxygenated form. One reason CO is toxic is that it competes with O2 in binding to Hb:Hb•O2(aq) + CO(g) ⥫⥬ Hb•CO(aq) + O 2(g)(b) How is Le Châtelier’s principle used to treat CO poisoning?
Water gas, a mixture of H2 and CO, is an important industrial fuel produced by the reaction of steam with red hot coke, essentially pure carbon.(a) Write the expression for the equilibrium constant for the reversible reactionC(s) + H2O(g) ⇌ CO(g) + H2(g) ΔH = 131.30 kJ(b) What will happen to the concentration of each reactant and product at equilibrium if more C is added?(c) What will happen to the concentration of each reactant and product at equilibrium if H2O is removed?(d) What will happen to the concentration of each reactant and product at equilibrium if CO is added?(e) What will happen to the concentration of each reactant and product at equilibrium if the temperature of the system is increased?
An important industrial source of ethanol is the reaction, catalyzed by H 3PO4, of steam with ethylene derived from oil:   C2H4(g) + H2O(g) ⇌ C2H5OH(g)     ΔH°rxn = −47.8 kJ      Kc = 9 x 103 at 600. K(d) In NH3 manufacture, the yield is increased by condensing the NH 3 to a liquid and removing it. Would condensing the C2H5OH have the same effect in ethanol production? Explain.
Consider the following system at equilibrium. S(s) + O2(g) ⇌ SO2(g) a. How will adding more S(s) shift the equilibrium? b. How will removing some SO2(g) shift the equilibrium? c. How will decreasing the volume of the container shift the equilibrium?
At a particular temperature, Kp = 0.25 for the reaction N2O4(g) ⇌ 2NO2(g)a. A flask containing only N2O4 at an initial pressure of 4.5 atm is allowed to reach equilibrium. Calculate the equilibrium partial pressures of the gases.b. A flask containing only NO2 at an initial pressure of 9.0 atm is allowed to reach equilibrium. Calculate the equilibrium partial pressures of the gases.c. From your answers to parts a and b, does it matter from which direction an equilibrium position is reached?
Pure iron metal can be produced by the reduction of iron(III) oxide with hydrogen gas. (a) Write the expression for the equilibrium constant (Kc) for the reversible reactionFe2O3(s) + 3H2(g) ⇌ 2Fe(s) + 3H2 O(g) ΔH = 98.7 kJ(b) What will happen to the concentration of each reactant and product at equilibrium if more Fe is added?(c) What will happen to the concentration of each reactant and product at equilibrium if H2O is removed?(d) What will happen to the concentration of each reactant and product at equilibrium if H2 is added?(e) What will happen to the concentration of each reactant(f) What will happen to the concentration of each reactant and product at equilibrium if the temperature of the system is increased?
Suppose the reaction systemUO2(s) + 4HF(g) ⇌ UF4(g) + 2H2O(g)has already reached equilibrium. Predict the effect that each of the following changes will have on the equilibrium position. Tell whether the equilibrium will shift to the right, will shift to the left, or will not be affected.b. The reaction is performed in a glass reaction vessel; HF(g) attacks and reacts with glass.
Suppose the reaction systemUO2(s) + 4HF(g) ⇌ UF4(g) + 2H2O(g)has already reached equilibrium. Predict the effect that each of the following changes will have on the equilibrium position. Tell whether the equilibrium will shift to the right, will shift to the left, or will not be affected.c. Water vapor is removed.
Ammonia is a weak base that react with water according to this equation:NH3(aq) + H2 O(l) ⇌ NH4 +(aq) + OH−(aq)Will the following increase the percent of ammonia that is converted to the ammonium ion in water?(a) Addition of NaOH
Ammonia is a weak base that react with water according to this equation:NH3(aq) + H2 O(l) ⇌ NH4 +(aq) + OH−(aq)Will the following increase the percent of ammonia that is converted to the ammonium ion in water?(b) Addition of HCl
Ammonia is a weak base that react with water according to this equation:NH3(aq) + H2 O(l) ⇌ NH4 +(aq) + OH−(aq)Will the following increase the percent of ammonia that is converted to the ammonium ion in water?(c) Addition of NH4Cl
An important reaction in the commercial production of hydrogen isCO(g) + H2O(g) ⇌ H2(g) + CO2(g)How will this system at equilibrium shift in each of the following cases?a. Gaseous carbon dioxide is removed.
Acetic acid is a weak acid that react with water according to this equation:CH3 CO2 H(aq) + H2O(aq) ⇌ H3O+(aq) + CH3CO2 −(aq)Will the following increase the percent of acetic acid that react and produce CH 3 CO2 − ion?(a) Addition of HCl
An important reaction in the commercial production of hydrogen isCO(g) + H2O(g) ⇌ H2(g) + CO2(g)How will this system at equilibrium shift in each of the following cases?b. Water vapor is added.
Acetic acid is a weak acid that react with water according to this equation:CH3 CO2 H(aq) + H2O(aq) ⇌ H3O+(aq) + CH3CO2 −(aq)Will the following increase the percent of acetic acid that react and produce CH 3 CO2 − ion?(b) Addition of NaOH
Acetic acid is a weak acid that react with water according to this equation:CH3 CO2 H(aq) + H2O(aq) ⇌ H3O+(aq) + CH3CO2 −(aq)Will the following increase the percent of acetic acid that react and produce CH 3 CO2 − ion?(c) Addition of NaCH3CO2
What will happen to the number of moles of SO 3 in equilibrium with SO2 and O2 in the reaction2SO3(g) ⇌ 2SO2(g) + O2(g)in each of the following cases?a. Oxygen gas is added.
What will happen to the number of moles of SO 3 in equilibrium with SO2 and O2 in the reaction2SO3(g) ⇌ 2SO2(g) + O2(g)in each of the following cases?e. Gaseous sulfur dioxide is removed.
In which direction will the position of the equilibrium2HI(g) ⇌ H2(g) + I2(g)be shifted for each of the following changes?a. H2(g) is added.
In which direction will the position of the equilibrium2HI(g) ⇌ H2(g) + I2(g)be shifted for each of the following changes?b. I2(g) is removed.
In which direction will the position of the equilibrium2HI(g) ⇌ H2(g) + I2(g)be shifted for each of the following changes?c. HI(g) is removed.
Hydrogen for use in ammonia production is produced by the reactionWhat will happen to a reaction mixture at equilibrium ifa. H2O(g) is removed?
The binding of oxygen by hemoglobin (Hb), giving oxyhemoglobin (HbO2), is partially regulated by the concentration of H3O+ and dissolved CO2 in the blood. Although the equilibrium is complicated, it can be summarized as HbO2(aq) + H3 O+(aq) + CO2(g) ⇌ CO2 −Hb−H+ + O2(g) + H2 O(l)(b) Explain why the production of lactic acid and CO 2 in a muscle during exertion stimulates release of O2 from the oxyhemoglobin in the blood passing through the muscle.
Hydrogen for use in ammonia production is produced by the reactionWhat will happen to a reaction mixture at equilibrium ifd. CO(g) is removed?
Consider the following reaction at equilibrium: 2CO2 (g) <---> 2CO (g) + O2 (g) ΔH° = -514 kJ Le Chatelier's principle predicts that adding O2 (g) to the reaction container will __________. a. decrease the partial pressure of CO2 (g) at equilibrium b. decrease the value of the equilibrium constant c. increase the partial pressure of CO2 (g) at equilibrium d. increase the value of the equilibrium constant e. increase the partial pressure of CO (g) at equilibrium  
The minerals hematite (Fe2O3) and magnetite (Fe3O4) exist in equilibrium with atmospheric oxygen: 4Fe3O4(s) + O2(g) ⇌ 6Fe2O3(s) Kp = 2.5 x 1087 at 298 K(a) Determine PO2 at equilibrium.(b) Given that PO2 in air is 0.21 atm, in which direction will the reaction proceed to reach equilibrium?
Consider the following reaction at equilibrium: CO(g) + Cl2(g) ⇌ COCl2(g)Predict whether the reaction will shift left, shift right, or remain unchanged if COCl2 is added to the reaction mixture.
Consider the following reaction at equilibrium: CO(g) + Cl2(g) ⇌ COCl2(g)Predict whether the reaction will shift left, shift right, or remain unchanged if Cl2 is added to the reaction mixture.
Consider the following reaction at equilibrium: CO(g) + Cl2(g) ⇌ COCl2(g)Predict whether the reaction will shift left, shift right, or remain unchanged if COCl2 is removed from the reaction mixture.
Consider the following reaction at equilibrium: 2 KClO3(s) ⇌ 2 KCl(s) + 3 O2(g)Predict whether the reaction will shift left, shift right, or remain unchanged if O2 is removed from the reaction mixture.
Consider the following reaction at equilibrium: 2 KClO3(s) ⇌ 2 KCl(s) + 3 O2(g)Predict whether the reaction will shift left, shift right, or remain unchanged if O2 is added to the reaction mixture.
Consider the following system as equilibrium PbI2(s) = Pb2+(aq) + 2I-(aq)How will adding more PbI2 shift the equilibrium?How will removing some Pb2+ shift the equilibrium?
Explain how to recognize the conditions under which changes in pressure would affect systems at equilibrium.
The synthesis of ammonia gas from nitrogen gas and hydrogen gas represents a classic case in which a knowledge of kinetics and equilibrium was used to make a desired chemical reaction economically feasible. Explain how each of the following conditions helps to maximize the yield of ammonia.d. running the reaction at high pressure
At 25 °C and at 1 atm, the partial pressures in an equilibrium mixture of N  2O4 and NO2 are PN2O4 = 0.70 atm and PNO2 = 0.30 atm.(a) Predict how the pressures of NO 2 and N2O4 will change if the total pressure increases to 9.0 atm. Will they increase, decrease, or remain the same?
The “filmstrip” represents five molecular scenes of a gaseous mixture as it reaches equilibrium over time:X is purple and Y is orange: X2(g) + Y2(g) ⇌ 2XY(g). (f) Which scene, if any, best represents the mixture at a higher pressure (lower volume)? Explain.
What will happen to the number of moles of SO 3 in equilibrium with SO2 and O2 in the reaction2SO3(g) ⇌ 2SO2(g) + O2(g)in each of the following cases?c. In a rigid reaction container, the pressure is increased by adding argon gas.
Consider the equilibrium4NO2(g) + 6H2 O(g) ⇌ 4NH3(g) + 7O2(g)(c) If the reaction were at equilibrium, how would a decrease in pressure (from an increase in the volume of the reaction vessel) affect the pressure of NO2?
Consider the following reaction at equilibrium: 2CO2 (g) <---> 2CO (g) + O2 (g) ΔH° = -514 kJ Le Chatelier's principle predicts that the equilibrium partial pressure of CO (g) can be maximized by carrying out the reaction __________. a. at high temperature and high pressure b. at high temperature and low pressure c. at low temperature and low pressure d. at low temperature and high pressure e. in the presence of solid carbon
The reaction A(g) ⇌ 2B(g) has an equilibrium constant of Kc = 1.0 at a given temperature. If a reaction vessel contains equal initial amounts (in moles) of A and B, does the direction in which the reaction proceeds depend on the volume of the reaction vessel?
Consider the reactionFe3+(aq) + SCN -(aq) ⇌ FeSCN 2+(aq)How will the equilibrium position shift ifa. water is added, doubling the volume?
Consider the following reaction at chemical equilibrium: 2SO2(g) + O2(g) ⇌ 2SO3(g). What is the effect of decreasing the volume of the reaction mixture?
Consider the following reaction at chemical equilibrium: 2SO2(g) + O2(g) ⇌ 2SO3(g). What is the effect of increasing the volume of the reaction mixture?
Predict the effect of increasing the container volume on the amounts of the reactant and product in the following reaction:   (a) F2(g) ⇌ 2F(g) 
Predict the effect of increasing the container volume on the amounts of the reactant and product in the following reaction:   (b) 2CH4(g) ⇌ C2H2(g) + 3H2(g)
Predict the effect of increasing the container volume on the amounts of the reactant and product in the following reaction: (a) CH3OH(l) ⇌ CH3OH(g) 
Predict the effect of increasing the container volume on the amounts of the reactant and product in the following reaction: (b) CH4(g) + NH3(g) ⇌ HCN(g) + 3H2(g)
Predict the effect of decreasing the container volume on the amounts of the reactant and product in the following reaction:   (a) H2(g) + Cl2(g) ⇌ 2HCl(g) 
Predict the effect of decreasing the container volume on the amounts of the reactant and product in the following reaction:   (b) 2H2(g) + O2(g) ⇌ 2H2O(l)
Predict the effect of decreasing the container volume on the amounts of the reactant and product in the following reaction: (a) C3H8(g) + 5O2(g) ⇌ 3CO2(g) + 4H2O(l) 
Predict the effect of decreasing the container volume on the amounts of the reactant and product in the following reaction: (b) 4NH3(g) + 3O2(g) ⇌ 2N2(g) + 6H2O(g)
How would you adjust the volume of the container in order to maximize product yield in the following reaction?  (a) Fe3O4(s) + 4H2(g) ⇌ 3Fe(s) + 4H2O(g) 
How would you adjust the volume of the container in order to maximize product yield in the following reaction?  (b) 2C(s) + O2(g) ⇌ 2CO(g)
How would you adjust the volume of the container in order to maximize product yield in the following reaction? (a) Na2O2(s) ⇌ 2Na(l) + O2(g) 
How would you adjust the volume of the container in order to maximize product yield in the following reaction? (b) C2H2(g) + 2H2(g) ⇌ C2H6(g)
Predict the shift in the equilibrium position that will occur for each of the following reactions when the volume of the reaction container is increased.a. N2(g) + 3H2(g) ⇌ 2NH3(g)
Predict the shift in the equilibrium position that will occur for each of the following reactions when the volume of the reaction container is increased.b. PCl5(g) ⇌ PCl3(g) + Cl2(g)
Predict the shift in the equilibrium position that will occur for each of the following reactions when the volume of the reaction container is increased.c. H2(g) + F2(g) ⇌ 2HF(g)
Predict the shift in the equilibrium position that will occur for each of the following reactions when the volume of the reaction container is increased.d. COCl2(g) ⇌ CO(g) + Cl2(g)
Predict the shift in the equilibrium position that will occur for each of the following reactions when the volume of the reaction container is increased.e. CaCO3(s) ⇌ CaO(s) + CO2(g)
An important reaction in the commercial production of hydrogen isCO(g) + H2O(g) ⇌ H2(g) + CO2(g)How will this system at equilibrium shift in each of the following cases?e. The pressure is increased by decreasing the volume of the reaction container.
What will happen to the number of moles of SO 3 in equilibrium with SO2 and O2 in the reaction2SO3(g) ⇌ 2SO2(g) + O2(g)in each of the following cases?b. The pressure is increased by decreasing the volume of the reaction container.
In which direction will the position of the equilibrium2HI(g) ⇌ H2(g) + I2(g)be shifted for each of the following changes?e. The volume of the container is doubled.
Hydrogen for use in ammonia production is produced by the reactionWhat will happen to a reaction mixture at equilibrium ife. the volume of the container is tripled?
Each of the following reactions is allowed to come to equilibrium and then the volume is changed as indicated. Predict the effect (shift right, shift left, or no effect) of the indicated volume change.I2(g) ⇌ 2 I(g) (volume is increased)
Each of the following reactions is allowed to come to equilibrium and then the volume is changed as indicated. Predict the effect (shift right, shift left, or no effect) of the indicated volume change.2 H2S(g) ⇌ 2 H2(g) + S2(g) (volume is decreased)
Each of the following reactions is allowed to come to equilibrium and then the volume is changed as indicated. Predict the effect (shift right, shift left, or no effect) of the indicated volume change.I2(g) + Cl2(g) ⇌ 2 ICl(g) (volume is decreased)
Each of the following reactions is allowed to come to equilibrium and then the volume is changed as indicated. Predict the effect (shift right, shift left, or no effect) of the indicated volume change.a. CO(g) + H2O(g) ⇌ CO2(g) + H2(g) (volume is decreased)b. PCl3(g) + Cl2(g) ⇌ PCl5(g) (volume is increased)c. CaCO3(s) ⇌ CaO(s) + CO2(g) (volume is increased)
The decomposition of NH4HS is endothermic: NH4HS(s) ⇌ NH3(g) + H2S(g)Which change to an equilibrium mixture of this reaction results in the formation of more H2S?
The following equation represents a reversible decomposition:CaCO3(s) ⇌ CaO(s) + CO2(g)Under what conditions will decomposition in a closed container proceed to completion so that no CaCO3 remains?
Suggest four ways in which the concentration of hydrazine, N 2H4, could be increased in an equilibrium described by the following equation:N2(g) + 2H2(g) ⇌ N2 H4(g)                      ΔH = 95 kJ
Suggest four ways in which the concentration of PH 3 could be increased in an equilibrium described by the following equation:P4(g) + 6H2(g) ⇌ 4PH3(g)               ΔH = 110.5 kJ
For the following equilibrium system, which of the changes will form more CaCO  3? CO2(g) + Ca(OH)2(s) ⇌ CaCO3(s) + H2O(l)     ΔH° = −113 kJ (a) Decrease temperature at constant pressure (no phase change) (b) Increase volume at constant temperature (c) Increase partial pressure of CO2 (d) Remove one-half of the initial CaCO3
Consider the following exothermic reaction at equilibrium:N2(g) + 3H2(g) ⇌ 2NH3(g)Predict how the following changes affect the number of moles of each component of the system after equilibrium is reestablished by completing the table below. Complete the table with the terms increase, decrease, or no change.
For the following endothermic reaction at equilibrium:2SO3(g) ⇌ 2SO2(g) + O2(g)which of the following changes will increase the value of K?a. increasing the temperatureb. decreasing the temperaturec. removing SO3(g) (constant T)d. decreasing the volume (constant T)e. adding Ne(g) (constant T)f. adding SO2(g) (constant T)g. adding a catalyst (constant T)
Glauber’s salt, Na 2SO4·10H2O, was used by J. R. Glauber in the 17 th century as a medicinal agent. At 25°C, Kp = 4.08×10−25 for the loss of waters of hydration from Glauber’s salt:             Na 2SO4·10H2O(s) ⥫⥬ Na2SO4(s) + 10H2O(g)(b) How do the following changes affect the ratio (higher, lower, same) of hydrated form to anhydrous form for the system above?(1) Add more Na 2SO4(s)(2) Reduce the container volume(3) Add more water vapor(4) Add N2 gas
The equilibrium constant is 0.0900 at 25ºC for the reaction H2O(g) + Cl2O(g) ⇌ 2HOCl(g)For which of the following sets of conditions is the system at equilibrium? For those that are not at equilibrium, in which direction will the system shift? a. A 1.0-L flask contains 1.0 mole of HOCl, 0.10 mole of Cl 2O, and 0.10 mole of H2O.b. A 2.0-L flask contains 0.084 mole of HOCl, 0.080 mole of Cl 2O, and 0.98 mole of H2O. c. A 3.0-L flask contains 0.25 mole of HOCl, 0.0010 mole of Cl 2O, and 0.56 mole of H2O.
An important industrial source of ethanol is the reaction, catalyzed by H 3PO4, of steam with ethylene derived from oil:   C2H4(g) + H2O(g) ⇌ C2H5OH(g)     ΔH°rxn = −47.8 kJ      K c = 9 x 103 at 600. K(b) Is the highest yield of ethanol obtained at high or low P? High or low T? 
Suggest two ways in which the equilibrium concentration of Ag + can be reduced in a solution of Na+, Cl−, Ag+, and NO3 −, in contact with solid AgCl.Na+(aq) + Cl−(aq) + Ag+(aq) + NO3 −(aq) ⇌ AgCl(s) + Na +(aq) + NO3 −(aq) ΔH = −65.9 kJ
How can the pressure of water vapor be increased in the following equilibrium?H2O(l) ⇌ H2O(g)                                                       ΔH = 41 kJ
The oxidation of SO2 is the key step in H2SO4 production:   SO2(g) + ½O2(g) ⇌ SO3(g)  ΔH°rxn = −99.2 kJ(a) What qualitative combination of T and P maximizes SO 3 yield? 
Coal, which is primarily carbon, can be converted to natural gas, primarily CH4, by the following exothermic reaction:C(s) + 2 H2(g) ⇌ CH4(g)Which of the following will favor CH4 at equilibrium?a. adding more C to the reaction mixtureb. adding more H2 to the reaction mixturec. raising the temperature of the reaction mixtured. lowering the volume of the reaction mixturee. adding a catalyst to the reaction mixturef. adding neon gas to the reaction mixture
Consider the following exothermic reaction: C2H4(g) + Cl2(g) ⇌ C2H4Cl2(g)If you were a chemist trying to maximize the amount of C2H4Cl2 produced, which of the following might you try? Assume that the reaction mixture reaches equilibrium.– Increasing the reaction volume– Removing C2 H4 Cl2 from the reaction mixture as it forms– Lowering the reaction temperature– Adding Cl2
Consider the following endothermic reaction: C2H4(g) + I2(g) ⇌ C2H4I2(g)If you were trying to maximize the amount of C2 H4 I2 produced, which of the following might you try? Assume that the reaction mixture reaches equilibrium.– Decreasing the reaction volume– Removing I2 from the reaction mixture– Raising the reaction temperature– Adding C2H4 to the reaction mixture
2AB (aq) ⇌ A 2 (aq) B2 (aq)  The above reaction is at equilibrium. I begin to remove A 2 from the system. How does this affect equilibrium? 
At a certain temperature, the equilibrium constant, K c, for the reaction Cl2(g) ⇌ 2Cl(g) is 5.92 x 104. A. If 2.77 g of Cl 2 are placed in a 2.50 L flask at this temperature, what are the equilibrium concentrations of Cl2 and Cl? B. Following the establishment of equilibrium in part A, the volume of the flask is suddenly increased to 4.00 L while the temperature is held constant. What are the new equilibrium concentrations of Cl2 and Cl? C. Following the establishment of equilibrium in part A, the volume of the flask is instead suddenly decreased to 1.00 L while the temperature is held constant. What are the new equilibrium concentrations of Cl2 and Cl?
 Consider the following system at equilibrium.a. How will adding more CaCl2 shift the equilibrium?b. How will removing some Ca2+ shift the equilibrium?  
As the temperature of an endothermic equilibrium reaction increases, the equilibrium will shift to the left.a. Trueb. False 
Consider this system at equilibrium. PCl3(g) + Cl2(g) ⇌ PCI5(g) + heat How will the system respond to a temperature increase? a. shift leftb. shift rightc. no change