Question 1

Once the reaction quotient, Q, has been determined for a reaction mixture, comparison with the value of the equilibrium constant, K, will determine

Accepted Answer

A)  if the mixture is at equilibrium or not. 
B)  if the mixture has an excess of either products or reactants compared to equilibrium. 
C)  if the mixture will react to the left, to the right, or not at all. 
D)  Both a and b. 
E)  All of a, b, and c. 
A)  if the mixture is at equilibrium or not. 
B)  if the mixture has an excess of either products or reactants compared to equilibrium. 
C)  if the mixture will react to the left, to the right, or not at all. 
D)  Both a and b. 
E)  All of a, b, and c.

Question 2

For the reaction   Kc = 1.4 × 1015. In an equilibrium mixture, [A] = 0.45 M. What is the concentration of B?

Accepted Answer

A)  2.8 × 1014 
B)  0.90 
C)  1.1 × 1015 
D)  6.3 × 1014 
E)  2.5 × 107 
A)  2.8 × 1014 
B)  0.90 
C)  1.1 × 1015 
D)  6.3 × 1014 
E)  2.5 × 107

Question 3

If the equilibrium constants for the two reactions   and
  
are denoted K1 and K2 respectively, then the equilibrium constant for the reaction
  equals

Accepted Answer

A)  (K1/K2)2. 
B)  (K1K2)2. 
C)  K1K2. 
D)  K1 + K2. 
E)  K1K2/2. 
A)  (K1/K2)2. 
B)  (K1K2)2. 
C)  K1K2. 
D)  K1 + K2. 
E)  K1K2/2.

Question 4

Concerning the Haber-Bosch for the synthesis of ammonia,   which of the following is true?

Accepted Answer

A)  the reaction is strongly exothermic 
B)  the reaction is carried out at high pressure 
C)  ammonia is continually liquefied and removed from the process 
D)  the temperature is raised because the reaction is too slow at room temperature 
E)  all of these 
A)  the reaction is strongly exothermic 
B)  the reaction is carried out at high pressure 
C)  ammonia is continually liquefied and removed from the process 
D)  the temperature is raised because the reaction is too slow at room temperature 
E)  all of these

Question 5

The reaction
  is the basis of a very ancient chemical industry. Seashells or chalk (limestone) are roasted in kilns to produce CaO (quicklime). When moistened and used in a mortar, this forms Ca(OH)2 (slaked lime). Atmospheric CO2 slowly converts this back to CaCO3. A strong bond thus results between the stones used in the wall.
a. Is the above reaction exothermic or endothermic? Explain.
b. Lime kilns, since ancient times, have been designed with efficient chimneys to draw exhaust gases away. In terms of Le Chatelier's Principle, give two reasons why this enhances the conversion of limestone to quicklime.
c. When a sample of CaCO3(s) is placed in a sealed, evacuated container, the equilibrium CO2 pressure at a given temperature is always the same, and is not influenced by the amount of CaCO3, provided that there is still some present at equilibrium. Explain why.
d.	How would the result in Part c be affected by adding an equal number of moles of CaO to the flask? Explain.

Accepted Answer

a. The reaction is endothermic. It is cl

Question 6

For the reaction   Kc = 168. A mixture contains some C(s), [CO] = 0.50 M and [CO2] = 0.75 M. Therefore the system ____ at equilibrium, because ____.

Accepted Answer

A)  is not; the value of Q is 0.67 
B)  is not; the value of Q is 1.5 
C)  is; the value of Q is 0.67 
D)  is not; the value of Q is 0.33 
E)  is; the value of Q is 0.33 
A)  is not; the value of Q is 0.67 
B)  is not; the value of Q is 1.5 
C)  is; the value of Q is 0.67 
D)  is not; the value of Q is 0.33 
E)  is; the value of Q is 0.33

Question 7

This reaction is the basis for the Haber-Bosch process for the manufacture of ammonia:   To maximize the yield of ammonia, the pressure ____ and the temperature____.

Accepted Answer

A)  should be kept high by compressing the mixture; should be kept low 
B)  should be kept high by compressing the mixture; should be kept high 
C)  should be kept high by adding an inert gas; should be kept low 
D)  should be kept high by adding an inert gas; should be kept high 
E)  should be kept low; should be kept low 
A)  should be kept high by compressing the mixture; should be kept low 
B)  should be kept high by compressing the mixture; should be kept high 
C)  should be kept high by adding an inert gas; should be kept low 
D)  should be kept high by adding an inert gas; should be kept high 
E)  should be kept low; should be kept low

Question 8

For a particular chemical reaction, which of the following will result in a change of the equilibrium constant?

Accepted Answer

A)  a change in pressure 
B)  a change in the temperature 
C)  adding additional reactant 
D)  removing product 
E)  the equilibrium constant never changes 
A)  a change in pressure 
B)  a change in the temperature 
C)  adding additional reactant 
D)  removing product 
E)  the equilibrium constant never changes

Question 9

For the reaction   Kc = 0.0600 at a certain temperature. In an equilibrium mixture of the three gases, [NH3] = 0.242 M and [H2] = 1.03 M. What is the concentration of N2 in this system?

Accepted Answer

A)  3.9 M 
B)  3.2 × 10-3 M 
C)  0.89 M 
D)  1.4 × 10-2 M 
E)  3.7 M 
A)  3.9 M 
B)  3.2 × 10-3 M 
C)  0.89 M 
D)  1.4 × 10-2 M 
E)  3.7 M

Question 10

Consider the reaction   If the partial pressures in an equilibrium mixture of Br2, Cl2, and BrCl are 1.12 atm, 1.26 atm, and 3.14 atm, respectively, the value of Kp for this reaction at this temperature is

Accepted Answer

A)  6.99 
B)  4.70 
C)  1.91 
D)  0.532 
E)  0.142 
A)  6.99 
B)  4.70 
C)  1.91 
D)  0.532 
E)  0.142

Question 11

A chemical equilibrium may involve

Accepted Answer

A)  reactants and products exhibiting different states of matter 
B)  molecular rearrangements 
C)  a chemical change of one compound into another 
D)  reaction of elements to produce one or more compounds 
E)  any of these 
A)  reactants and products exhibiting different states of matter 
B)  molecular rearrangements 
C)  a chemical change of one compound into another 
D)  reaction of elements to produce one or more compounds 
E)  any of these

Question 12

Consider the reaction   If the pressure is decreased on an equilibrium mixture of these three substances, equilibrium will ____, because ____.

Accepted Answer

A)  shift to the right; lower pressure favors fewer moles of gas 
B)  shift to the right; lower pressure favors more moles of gas 
C)  shift to the left; lower pressure favors fewer moles of gas 
D)  shift to the left; lower pressure favors more moles of gas 
E)  be unchanged; solid NH4Cl does not appear in the equilibrium constant expression. 
A)  shift to the right; lower pressure favors fewer moles of gas 
B)  shift to the right; lower pressure favors more moles of gas 
C)  shift to the left; lower pressure favors fewer moles of gas 
D)  shift to the left; lower pressure favors more moles of gas 
E)  be unchanged; solid NH4Cl does not appear in the equilibrium constant expression.

Question 13

Which statement concerning product-favored reactions is not correct?

Accepted Answer

A)  If a reaction is product-favored at high temperature, the entropy of the products is probably greater than the entropy of the reactants. 
B)  If a reaction is product-favored at low temperature, the enthalpy of the products is probably less than the enthalpy of the reactants. 
C)  If the entropy of the products is greater than the entropy of the reactants, the reaction is product-favored. 
D)  An endothermic reaction is product-favored. 
E)  The value of the equilibrium constant is greater than 1. 
A)  If a reaction is product-favored at high temperature, the entropy of the products is probably greater than the entropy of the reactants. 
B)  If a reaction is product-favored at low temperature, the enthalpy of the products is probably less than the enthalpy of the reactants. 
C)  If the entropy of the products is greater than the entropy of the reactants, the reaction is product-favored. 
D)  An endothermic reaction is product-favored. 
E)  The value of the equilibrium constant is greater than 1.

Question 14

If a reaction is product-favored on the basis of enthalpy and reactant-favored on the basis of entropy, then it most likely is ____ and ____ net moles of gas.

Accepted Answer

A)  exothermic; produces 
B)  exothermic; consumes 
C)  exothermic; neither produces nor consumes 
D)  endothermic; produces 
E)  endothermic; consumes 
A)  exothermic; produces 
B)  exothermic; consumes 
C)  exothermic; neither produces nor consumes 
D)  endothermic; produces 
E)  endothermic; consumes

Question 15

A weak acid is 5% ionized at equilibrium. Therefore we can say that the ionization reaction is ____-favored, because ____.

Accepted Answer

A)  product; the amount of products > the amount of reactants 
D)  product; the amount of products >> the amount of reactants 
E)  neither; not enough information is available to reach a conclusion 
A)  product; the amount of products > the amount of reactants 
D)  product; the amount of products >> the amount of reactants 
E)  neither; not enough information is available to reach a conclusion

Question 16

A chemical reaction reaches equilibrium when

Accepted Answer

A)  both the forward and reverse reactions stop 
B)  the forward and reverse reactions both occur at the same rate 
C)  all of the limiting reactant has been used up 
D)  all of the limiting reactant has been used up and all of the limiting product has been created 
E)  the actual yield of the reaction equals the theoretical yield 
A)  both the forward and reverse reactions stop 
B)  the forward and reverse reactions both occur at the same rate 
C)  all of the limiting reactant has been used up 
D)  all of the limiting reactant has been used up and all of the limiting product has been created 
E)  the actual yield of the reaction equals the theoretical yield

Question 17

The equilibrium constant for a particular chemical reaction is

Accepted Answer

A)  dependent on the total pressure of the reaction 
B)  dependent on the temperature of the reaction 
C)  a numerical value between -¥ and +¥ 
D)  unreliably determined if variable amounts of either solid or liquid reactants or products are present 
E)  both b and c 
A)  dependent on the total pressure of the reaction 
B)  dependent on the temperature of the reaction 
C)  a numerical value between -¥ and +¥ 
D)  unreliably determined if variable amounts of either solid or liquid reactants or products are present 
E)  both b and c

Question 18

Consider the reaction
   for which
   .
A sample of pure NOBr is isolated at low temperature. It is placed in a flask at a concentration of 0.200 M and warmed up to 50$\circ$C. When the reaction has come to equilibrium, the concentration of NOBr is 0.176 M. What is the value of Kc at 50$\circ$C for this reaction?

Accepted Answer

Set up the reaction table as d

Question 19

A particular chemical reaction is

Accepted Answer

A)  reactant-favored if the equilibrium constant is very large 
B)  product-favored if the equilibrium constant is very small 
C)  either product-favored or reactant-favored depending on the temperature of the reaction 
D)  either product-favored or reactant-favored depending on the pressure of the reaction 
E)  all of these 
A)  reactant-favored if the equilibrium constant is very large 
B)  product-favored if the equilibrium constant is very small 
C)  either product-favored or reactant-favored depending on the temperature of the reaction 
D)  either product-favored or reactant-favored depending on the pressure of the reaction 
E)  all of these

Question 20

For the reaction  Kc = 0.95. A mixture of the three substances contains 0.45 M ethanol, 0.45 M acetic acid and 1.1 M ethyl acetate. Which statement is true?

Accepted Answer

A)  Q  K, so the system will react left to right. 
E)  Q > K, so the system will react right to left. 
A)  Q  K, so the system will react left to right. 
E)  Q > K, so the system will react right to left.

Once the reaction quotient, Q, has been determined for a reaction mixture, comparison with the value of the equilibrium constant, K, will determine

For the reaction K_c = 1.4 × 10¹⁵. In an equilibrium mixture, [A] = 0.45 M. What is the concentration of B?

If the equilibrium constants for the two reactions and are denoted K₁ and K₂ respectively, then the equilibrium constant for the reaction equals

Concerning the Haber-Bosch for the synthesis of ammonia, which of the following is true?

For the reaction K_c = 168. A mixture contains some C(s), [CO] = 0.50 M and [CO₂] = 0.75 M. Therefore the system at equilibrium, because .

This reaction is the basis for the Haber-Bosch process for the manufacture of ammonia: To maximize the yield of ammonia, the pressure and the temperature.

For a particular chemical reaction, which of the following will result in a change of the equilibrium constant?

For the reaction K_c = 0.0600 at a certain temperature. In an equilibrium mixture of the three gases, [NH₃] = 0.242 M and [H₂] = 1.03 M. What is the concentration of N₂ in this system?

Consider the reaction If the partial pressures in an equilibrium mixture of Br₂, Cl₂, and BrCl are 1.12 atm, 1.26 atm, and 3.14 atm, respectively, the value of K_p for this reaction at this temperature is

A chemical equilibrium may involve

Consider the reaction If the pressure is decreased on an equilibrium mixture of these three substances, equilibrium will , because .

Which statement concerning product-favored reactions is not correct?

If a reaction is product-favored on the basis of enthalpy and reactant-favored on the basis of entropy, then it most likely is and net moles of gas.

A weak acid is 5% ionized at equilibrium. Therefore we can say that the ionization reaction is -favored, because .

A chemical reaction reaches equilibrium when

The equilibrium constant for a particular chemical reaction is

A particular chemical reaction is

For the reaction K_c = 0.95. A mixture of the three substances contains 0.45 M ethanol, 0.45 M acetic acid and 1.1 M ethyl acetate. Which statement is true?

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Exam 13: Chemical Equilibrium

Once the reaction quotient, Q, has been determined for a reaction mixture, comparison with the value of the equilibrium constant, K, will determine

For the reaction Kc = 1.4 × 1015. In an equilibrium mixture, [A] = 0.45 M. What is the concentration of B?

If the equilibrium constants for the two reactions and are denoted K1 and K2 respectively, then the equilibrium constant for the reaction equals

Concerning the Haber-Bosch for the synthesis of ammonia, which of the following is true?

For the reaction Kc = 168. A mixture contains some C(s), [CO] = 0.50 M and [CO2] = 0.75 M. Therefore the system ____ at equilibrium, because ____.

This reaction is the basis for the Haber-Bosch process for the manufacture of ammonia: To maximize the yield of ammonia, the pressure ____ and the temperature____.

For a particular chemical reaction, which of the following will result in a change of the equilibrium constant?

For the reaction Kc = 0.0600 at a certain temperature. In an equilibrium mixture of the three gases, [NH3] = 0.242 M and [H2] = 1.03 M. What is the concentration of N2 in this system?

Consider the reaction If the partial pressures in an equilibrium mixture of Br2, Cl2, and BrCl are 1.12 atm, 1.26 atm, and 3.14 atm, respectively, the value of Kp for this reaction at this temperature is

A chemical equilibrium may involve

Consider the reaction If the pressure is decreased on an equilibrium mixture of these three substances, equilibrium will ____, because ____.

Which statement concerning product-favored reactions is not correct?

If a reaction is product-favored on the basis of enthalpy and reactant-favored on the basis of entropy, then it most likely is ____ and ____ net moles of gas.

A weak acid is 5% ionized at equilibrium. Therefore we can say that the ionization reaction is ____-favored, because ____.

A chemical reaction reaches equilibrium when

The equilibrium constant for a particular chemical reaction is

A particular chemical reaction is

For the reaction Kc = 0.95. A mixture of the three substances contains 0.45 M ethanol, 0.45 M acetic acid and 1.1 M ethyl acetate. Which statement is true?

The Nature of Chemistry

Atoms and Elements

Chemical Compounds

Quantities of Reactants and Products

Chemical Reactions

Energy and Chemical Reactions

Electron Configurations and the Periodic Table

Covalent Bonding

Molecular Structure

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Liquids, Solids, and Materials

Chemical Kinetics: Rates of Reactions

The Chemistry of Solutes and Solutions

Acids and Bases

Additional Aqueous Equilibria

Thermodynamics: Directionality of Chemical Reactions

Electrochemistry and Its Applications

Nuclear Chemistry

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For the reaction K_c = 1.4 × 10¹⁵. In an equilibrium mixture, [A] = 0.45 M. What is the concentration of B?

If the equilibrium constants for the two reactions and are denoted K₁ and K₂ respectively, then the equilibrium constant for the reaction equals

For the reaction K_c = 168. A mixture contains some C(s), [CO] = 0.50 M and [CO₂] = 0.75 M. Therefore the system at equilibrium, because .

This reaction is the basis for the Haber-Bosch process for the manufacture of ammonia: To maximize the yield of ammonia, the pressure and the temperature.

For the reaction K_c = 0.0600 at a certain temperature. In an equilibrium mixture of the three gases, [NH₃] = 0.242 M and [H₂] = 1.03 M. What is the concentration of N₂ in this system?

Consider the reaction If the partial pressures in an equilibrium mixture of Br₂, Cl₂, and BrCl are 1.12 atm, 1.26 atm, and 3.14 atm, respectively, the value of K_p for this reaction at this temperature is

Consider the reaction If the pressure is decreased on an equilibrium mixture of these three substances, equilibrium will , because .

If a reaction is product-favored on the basis of enthalpy and reactant-favored on the basis of entropy, then it most likely is and net moles of gas.

A weak acid is 5% ionized at equilibrium. Therefore we can say that the ionization reaction is -favored, because .

For the reaction K_c = 0.95. A mixture of the three substances contains 0.45 M ethanol, 0.45 M acetic acid and 1.1 M ethyl acetate. Which statement is true?