Question 1

What is the mass-action expression, Qc, for the following chemical reaction?

Accepted Answer

A)    
B)    
C)    
D)    
E)  None of these choices is correct. 
A)    
B)    
C)    
D)    
E)  None of these choices is correct.

Question 2

A container was charged with hydrogen, nitrogen, and ammonia gases at 120 $\degree$C and the system was allowed to reach equilibrium. What will happen if the volume of the container is increased at constant temperature?

Accepted Answer

A)  There will be no effect. 
B)  More ammonia will be produced at the expense of hydrogen and nitrogen. 
C)  Hydrogen and nitrogen will be produced at the expense of ammonia. 
D)  The equilibrium constant will increase. 
E)  The equilibrium constant will decrease. 
A)  There will be no effect. 
B)  More ammonia will be produced at the expense of hydrogen and nitrogen. 
C)  Hydrogen and nitrogen will be produced at the expense of ammonia. 
D)  The equilibrium constant will increase. 
E)  The equilibrium constant will decrease.

Question 3

Unless $\Delta$H$\degree$rxn = 0, a change in temperature will affect the value of the equilibrium constant Kc.

Accepted Answer

A) True 
 B)False

Question 4

For some gas-phase reactions, Kp = Kc.

Accepted Answer

A) True 
 B)False

Question 5

Given this equilibrium constant data at 25 $\degree$C,   what is the value of Kc at this temperature for the reaction

Accepted Answer

A)  6.5 * 10¯8 
B)  1.3 * 10¯11 
C)  7.8 *1010 
D)  1.5 * 107 
E)  None of these choices is correct. 
A)  6.5 * 10¯8 
B)  1.3 * 10¯11 
C)  7.8 *1010 
D)  1.5 * 107 
E)  None of these choices is correct.

Question 6

If all of the coefficients in the balanced equation for an equilibrium reaction are doubled, then the value of the equilibrium constant, Kc, will also be doubled.

Accepted Answer

A) True 
 B)False

Question 7

About half of the sodium carbonate produced is used in making glass products because it lowers the melting point of sand, the major component of glass. When sodium carbonate is added to water, it hydrolyses according to the following reactions.   What is the value of K3?

Accepted Answer

A)  K1 *K2 
B)  K1 ¸ K2 
C)  K1 + K2 
D)  K1 - K2 
E)  (K1K2)2 
A)  K1 *K2 
B)  K1 ¸ K2 
C)  K1 + K2 
D)  K1 - K2 
E)  (K1K2)2

Question 8

When a chemical system is at equilibrium,

Accepted Answer

A)  the concentrations of the reactants are equal to the concentrations of the products. 
B)  the concentrations of the reactants and products have reached constant values. 
C)  the forward and reverse reactions have stopped. 
D)  the reaction quotient, Q, has reached a maximum. 
E)  the reaction quotient, Q, has reached a minimum. 
A)  the concentrations of the reactants are equal to the concentrations of the products. 
B)  the concentrations of the reactants and products have reached constant values. 
C)  the forward and reverse reactions have stopped. 
D)  the reaction quotient, Q, has reached a maximum. 
E)  the reaction quotient, Q, has reached a minimum.

Question 9

At 500 $\degree$C, the equilibrium constant, Kp, is 4.00 *10¯4 for the equilibrium:

Accepted Answer

A)  2.00* 10¯4 
B)  -4.00*10¯4 
C)  1.25 *103 
D)  2.50 * 103 
E)  4.00 * 104 
A)  2.00* 10¯4 
B)  -4.00*10¯4 
C)  1.25 *103 
D)  2.50 * 103 
E)  4.00 * 104

Question 10

The reaction system   is at equilibrium. Which of the following statements describes the behavior of the system if POCl is added to the container?

Accepted Answer

A)  The forward reaction will proceed to establish equilibrium. 
B)  The reverse reaction will proceed to establish equilibrium. 
C)  The partial pressures of POCl3 and POCl will remain steady while the partial pressure of chlorine increases. 
D)  The partial pressure of chlorine remains steady while the partial pressures of POCl3 and POCl increase. 
E)  The partial pressure of chlorine will increase while the partial pressure of POCl decreases. 
A)  The forward reaction will proceed to establish equilibrium. 
B)  The reverse reaction will proceed to establish equilibrium. 
C)  The partial pressures of POCl3 and POCl will remain steady while the partial pressure of chlorine increases. 
D)  The partial pressure of chlorine remains steady while the partial pressures of POCl3 and POCl increase. 
E)  The partial pressure of chlorine will increase while the partial pressure of POCl decreases.

Question 11

Nitric oxide is formed in automobile exhaust when nitrogen and oxygen in air react at high temperatures.   The equilibrium constant Kp for the reaction is 0.0025 at 2127 $\degree$C. If a container is charged with 8.00 atm of nitrogen and 5.00 atm of oxygen and the mixture is allowed to reach equilibrium, what will be the equilibrium partial pressure of nitrogen?

Accepted Answer

A)  0.16 atm 
B)  0.31 atm 
C)  3.1 atm 
D)  7.7 atm 
E)  7.8 atm 
A)  0.16 atm 
B)  0.31 atm 
C)  3.1 atm 
D)  7.7 atm 
E)  7.8 atm

Question 12

The equilibrium constant, Kp, has a value of 6.5 *10¯4 at 308 K for the reaction of nitrogen monoxide with chlorine.   What is the value of Kc?

Accepted Answer

A)  2.5 * 10¯7 
B)  6.5 * 10¯4 
C)  1.6 * 10¯2 
D)  1.7 
E)  None of these choices is correct. 
A)  2.5 * 10¯7 
B)  6.5 * 10¯4 
C)  1.6 * 10¯2 
D)  1.7 
E)  None of these choices is correct.

Question 13

Hydrogen sulfide will react with water as shown in the following reactions.   What is the value of K2?

Accepted Answer

A)  1.3 * 10¯27 
B)  2.3 *10¯7 
C)  1.3 * 10¯13 
D)  7.7 *1012 
E)  7.7 * 1026 
A)  1.3 * 10¯27 
B)  2.3 *10¯7 
C)  1.3 * 10¯13 
D)  7.7 *1012 
E)  7.7 * 1026

Question 14

(p. Various sections) Which of the following has an effect on the magnitude of the equilibrium constant?

Accepted Answer

A)  removing products as they are formed 
B)  adding more of a reactant 
C)  adding a catalyst 
D)  increasing the pressure, in a gas-phase reaction 
E)  change in temperature 
A)  removing products as they are formed 
B)  adding more of a reactant 
C)  adding a catalyst 
D)  increasing the pressure, in a gas-phase reaction 
E)  change in temperature

Question 15

Hydrogen sulfide can be formed in the following reaction:   The equilibrium constant Kp = 106 at 1023 K. Estimate the value of Kp at 1218 K.

Accepted Answer

A)  5.05 
B)  18.8 
C)  34.7 
D)  88.9 
E)  598 
A)  5.05 
B)  18.8 
C)  34.7 
D)  88.9 
E)  598

Question 16

The equilibrium constant for the reaction of bromine with chlorine to form bromine monochloride is

Accepted Answer

A)  2.97 *10¯4 
B)  1.72 *10¯2 
C)  3.45 * 10¯2 
D)  1.31 *10¯1 
E)  > 1.00 
A)  2.97 *10¯4 
B)  1.72 *10¯2 
C)  3.45 * 10¯2 
D)  1.31 *10¯1 
E)  > 1.00

Question 17

The equilibrium constant for reaction (1) below is 276. Under the same conditions, what is the equilibrium constant of reaction (2)?

Accepted Answer

A)  6.02 * 10¯2 
B)  7.25 * 10¯3 
C)  3.62 *10¯3 
D)  1.31 * 10¯5 
E)  None of these choices is correct. 
A)  6.02 * 10¯2 
B)  7.25 * 10¯3 
C)  3.62 *10¯3 
D)  1.31 * 10¯5 
E)  None of these choices is correct.

Question 18

SO2 reacts with O2 to produce SO3. If 86.0 g of SO2 is placed in a reaction vessel along with excess oxygen gas, how many moles of SO2 remain when 50.0 g of SO3 have been formed?

Accepted Answer

A)  0.56 mol 
B)  0.62 mol 
C)  0.72 mol 
D)  0.78 mol 
E)  1.34 mol 
A)  0.56 mol 
B)  0.62 mol 
C)  0.72 mol 
D)  0.78 mol 
E)  1.34 mol

Question 19

Write the mass-action expression, Qc, for the following chemical reaction.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 20

Consider the equilibrium reaction shown below. B2(g)   2B(g)
If the rate constants are: kfwd = 7.00 * 10¯5 s¯1 and krev = 2.00 * 10¯5 L mol¯1 s¯1, what is the value of Kc under these conditions?

Accepted Answer

A)  1.75 * 105 
B)  3.50 
C)  0.286 
D)  5.71 *10¯6 
E)  1.40 * 10¯10 
A)  1.75 * 105 
B)  3.50 
C)  0.286 
D)  5.71 *10¯6 
E)  1.40 * 10¯10

Exam 17: Equilibrium: the Extent of Chemical Reactions

What is the mass-action expression, Qc, for the following chemical reaction?

A container was charged with hydrogen, nitrogen, and ammonia gases at 120 °\degree° C and the system was allowed to reach equilibrium. What will happen if the volume of the container is increased at constant temperature?

Unless Δ\DeltaΔ H °\degree° rxn = 0, a change in temperature will affect the value of the equilibrium constant Kc.

For some gas-phase reactions, Kp = Kc.

Given this equilibrium constant data at 25 °\degree° C, what is the value of Kc at this temperature for the reaction

If all of the coefficients in the balanced equation for an equilibrium reaction are doubled, then the value of the equilibrium constant, Kc, will also be doubled.

About half of the sodium carbonate produced is used in making glass products because it lowers the melting point of sand, the major component of glass. When sodium carbonate is added to water, it hydrolyses according to the following reactions. What is the value of K3?

When a chemical system is at equilibrium,

At 500 °\degree° C, the equilibrium constant, Kp, is 4.00 *10¯4 for the equilibrium:

The reaction system is at equilibrium. Which of the following statements describes the behavior of the system if POCl is added to the container?

The equilibrium constant, Kp, has a value of 6.5 *10¯4 at 308 K for the reaction of nitrogen monoxide with chlorine. What is the value of Kc?

Hydrogen sulfide will react with water as shown in the following reactions. What is the value of K2?

(p. Various sections) Which of the following has an effect on the magnitude of the equilibrium constant?

Hydrogen sulfide can be formed in the following reaction: The equilibrium constant Kp = 106 at 1023 K. Estimate the value of Kp at 1218 K.

The equilibrium constant for the reaction of bromine with chlorine to form bromine monochloride is

The equilibrium constant for reaction (1) below is 276. Under the same conditions, what is the equilibrium constant of reaction (2)?

SO2 reacts with O2 to produce SO3. If 86.0 g of SO2 is placed in a reaction vessel along with excess oxygen gas, how many moles of SO2 remain when 50.0 g of SO3 have been formed?

Write the mass-action expression, Qc, for the following chemical reaction.

Consider the equilibrium reaction shown below. B2(g) 2B(g) If the rate constants are: kfwd = 7.00 * 10¯5 s¯1 and krev = 2.00 * 10¯5 L mol¯1 s¯1, what is the value of Kc under these conditions?

Keys to the Study of Chemistry

The Components of Matter

Stoichiometry of Formulas and Equations

Three Major Classes of Chemical Reactions

Gases and the Kinetic-Molecular Theory

Thermochemistry: Energy Flow and Chemical Change

Quantum Theory and Atomic Structure

Electron Configuration and Chemical Periodicity

Models of Chemical Bonding

The Shapes of Molecules

Theories of Covalent Bonding

Intermolecular Forces: Liquids, Solids, and Phase Changes

The Properties of Mixtures: Solutions and Colloids

Periodic Patterns in the Main-Group Elements

Organic Compounds and the Atomic Properties of Carbon

Kinetics: Rates and Mechanisms of Chemical Reactions

Acid-Base Equilibria

Ionic Equilibria in Aqueous Systems

Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

Electrochemistry: Chemical Change and Electrical Work

The Elements in Nature and Industry

The Transition Elements and Their Coordination Compounds

Nuclear Reactions and Their Applications

Filters

What is the mass-action expression, Q_c, for the following chemical reaction?

Unless $\Delta$ H $\degree$ _rxn = 0, a change in temperature will affect the value of the equilibrium constant K_c.

For some gas-phase reactions, K_p = K_c.

If all of the coefficients in the balanced equation for an equilibrium reaction are doubled, then the value of the equilibrium constant, K_c, will also be doubled.

About half of the sodium carbonate produced is used in making glass products because it lowers the melting point of sand, the major component of glass. When sodium carbonate is added to water, it hydrolyses according to the following reactions. What is the value of K₃?

At 500 $\degree$ C, the equilibrium constant, K_p, is 4.00 10¯⁴ for the equilibrium: $At 500 \degree C, the equilibrium constant, K<sub>p</sub>, is 4.00 10¯<sup>4</sup> for the equilibrium:$

The equilibrium constant, K_p, has a value of 6.5 *10¯⁴ at 308 K for the reaction of nitrogen monoxide with chlorine. What is the value of K_c?

Hydrogen sulfide will react with water as shown in the following reactions. What is the value of K₂?

Hydrogen sulfide can be formed in the following reaction: The equilibrium constant K_p = 106 at 1023 K. Estimate the value of K_p at 1218 K.

SO₂ reacts with O₂ to produce SO₃. If 86.0 g of SO₂ is placed in a reaction vessel along with excess oxygen gas, how many moles of SO₂ remain when 50.0 g of SO₃ have been formed?

Write the mass-action expression, Q_c, for the following chemical reaction.

Consider the equilibrium reaction shown below. B₂(g) 2B(g) If the rate constants are: k_fwd = 7.00 * 10¯⁵ s¯¹ and k_rev = 2.00 * 10¯⁵ L mol¯¹ s¯¹, what is the value of K_c under these conditions?