Question 1

If F1F1F1S1F1F1F10F1F1F1S1F1F1F10   for a reaction is F1F1F1S1F1F1F102.03 kJ/mol, what is K for the reaction at 300 K?

Accepted Answer

A) 3.16 F1F1F1S1F1F1F10 107 
B) 5.44 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F105 
C) 1.00 
D) 2.26 
E) 0.443 
A) 3.16 F1F1F1S1F1F1F10 107 
B) 5.44 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F105 
C) 1.00 
D) 2.26 
E) 0.443 D

Question 2

Indicate which of the following has the largest standard molar entropy (S F1F1F1S1F1F1F10).

Accepted Answer

A) CH4(g) 
B) CH3CH2OH(l ) 
C) CO2(s) 
D) Na(s) 
E) NH3(l ) 
A) CH4(g) 
B) CH3CH2OH(l ) 
C) CO2(s) 
D) Na(s) 
E) NH3(l ) A

Question 3

The entropy of fusion for ice at 0F1F1F1S1F1F1F10C and 1 atm is 22 J/mol F1F1F1S1F1F1F10 K. How many joules of heat are required to melt a typical ice cube at 0F1F1F1S1F1F1F10C and 1 atm? Assume an ice cube is about 1 oz or 28
g.

Accepted Answer

9,300 J

Question 4

The equilibrium constant for a given reaction ________

Accepted Answer

A) does not change with temperature. 
B) always increases with temperature. 
C) always decreases with temperature. 
D) increases with temperature for exothermic reactions only. 
E) increases with temperature for endothermic reactions only. 
A) does not change with temperature. 
B) always increases with temperature. 
C) always decreases with temperature. 
D) increases with temperature for exothermic reactions only. 
E) increases with temperature for endothermic reactions only.

Question 5

Determine the entropy change for the reaction   given the following information:

Accepted Answer

A) (F1F1F1S1F1F1F10196.4 J/K) 
B) (F1F1F1S1F1F1F10196.4 J/K) 
C) (F1F1F1S1F1F1F1093.9 J/K) 
D) (F1F1F1S1F1F1F1093.9 J/K) 
E) (F1F1F1S1F1F1F10401.4 J/K) 
A) (F1F1F1S1F1F1F10196.4 J/K) 
B) (F1F1F1S1F1F1F10196.4 J/K) 
C) (F1F1F1S1F1F1F1093.9 J/K) 
D) (F1F1F1S1F1F1F1093.9 J/K) 
E) (F1F1F1S1F1F1F10401.4 J/K)

Question 6

Which of the following is/are true for a reversible process at equilibrium?
I. F1F1F1S1F1F1F10Suniv F1F1F1S1F1F1F10 0
II. F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0
III. F1F1F1S1F1F1F10Gsys F1F1F1S1F1F1F10 0

Accepted Answer

A) I only 
B) II only 
C) III only 
D) I and III only 
E) I, II, and III are all true. 
A) I only 
B) II only 
C) III only 
D) I and III only 
E) I, II, and III are all true.

Question 7

Consider a closed container containing a 1 M solution of HCl, above which is air that contains water vapor at its equilibrium vapor pressure. Assume the pressure of the air and water vapor is 1 bar and the temperature of the system is 298 K. Which of the following is/are in its their thermodynamic standard state?
I. the liquid water
II. the HCl solution
III. the water vapor

Accepted Answer

A) I only 
B) II only 
C) III only 
D) I and II only 
E) I, II, and III are all in their standard states. 
A) I only 
B) II only 
C) III only 
D) I and II only 
E) I, II, and III are all in their standard states.

Question 8

What is the standard entropy change when 10.0 g of methane reacts with 10.0 g of oxygen?

Accepted Answer

A) (F1F1F1S1F1F1F10121 J/K) 
B) (F1F1F1S1F1F1F1037.9 J/K) 
C) (F1F1F1S1F1F1F10242.6 J/K) 
D) (F1F1F1S1F1F1F10154.4 J/K) 
E) (F1F1F1S1F1F1F1016.8 J/K) 
A) (F1F1F1S1F1F1F10121 J/K) 
B) (F1F1F1S1F1F1F1037.9 J/K) 
C) (F1F1F1S1F1F1F10242.6 J/K) 
D) (F1F1F1S1F1F1F10154.4 J/K) 
E) (F1F1F1S1F1F1F1016.8 J/K)

Question 9

Calculate the equilibrium constant at 500 K for the following reaction given the data below:
N2(g) F1F1F1S1F1F1F10 3H2(g)   2NH3(g)
Kc (298 K) F1F1F1S1F1F1F10 6.1 F1F1F1S1F1F1F10 105   (NH3, g) F1F1F1S1F1F1F10 F1F1F1S1F1F1F1016.5 kJ/mol   (NH3, g) F1F1F1S1F1F1F10 F1F1F1S1F1F1F1046.1 kJ/mol

Accepted Answer

Question 10

Before class, students were seated at three tables. When the school alarm went off suddenly, all the students distributed throughout the room to collect their belongings. The entropy of the class ________

Accepted Answer

A) increased. 
B) decreased. 
C) remained the same. 
D) cannot be determined. 
E) is irrelevant. 
A) increased. 
B) decreased. 
C) remained the same. 
D) cannot be determined. 
E) is irrelevant.

Question 11

Which statement about the reaction below, where en F1F1F1S1F1F1F10 ethylenediamine (H2NCH2CH2NH2), is not correct?

Accepted Answer

A) The reaction is product-favored because the entropy of the system increases. 
B) The Lewis basicity of the amino groups in en is comparable to that of the ammonia molecules. 
C) The reaction is reactant-favored because the concentration of ammonia on the right side is higher than the concentration of en on the left side. 
D) The reaction enthalpy is small because the Cr-NH3 and Cr-en bond strengths are very similar. 
E) Both Cr(NH3)63F1F1F1S1F1F1F10 and Cr(en)33F1F1F1S1F1F1F10 have an octahedral coordination geometry and a coordination number of 6. 
A) The reaction is product-favored because the entropy of the system increases. 
B) The Lewis basicity of the amino groups in en is comparable to that of the ammonia molecules. 
C) The reaction is reactant-favored because the concentration of ammonia on the right side is higher than the concentration of en on the left side. 
D) The reaction enthalpy is small because the Cr-NH3 and Cr-en bond strengths are very similar. 
E) Both Cr(NH3)63F1F1F1S1F1F1F10 and Cr(en)33F1F1F1S1F1F1F10 have an octahedral coordination geometry and a coordination number of 6.

Question 12

Indicate which one of the following reactions results in a positive F1F1F1S1F1F1F10Ssys.

Accepted Answer

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

Question 13

Which of the following is in the correct order of standard state entropy?
I. diamond F1F1F1S1F1F1F10 graphite
II. liquid water F1F1F1S1F1F1F10 solid water
III. NH3 F1F1F1S1F1F1F10 H2

Accepted Answer

A) I only 
B) II only 
C) III only 
D) I and II only 
E) I and III only 
A) I only 
B) II only 
C) III only 
D) I and II only 
E) I and III only

Question 14

The symbol F1F1F1S1F1F1F10F1F1F1S1F1F1F10   (CH4, g) refers to which of the following reactions?

Accepted Answer

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

Question 15

A sketch of the free energy for a hypothetical chemical equilibrium is shown here. What part of the plot on the axis representing the relative quantities of reactants and products corresponds to a value of Q that is less than K?

Accepted Answer

A) a to b 
B) b to c 
C) a to c 
D) b to d 
E) c to d 
A) a to b 
B) b to c 
C) a to c 
D) b to d 
E) c to d

Question 16

A reaction is not spontaneous at any temperature. What are the signs for F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 and F1F1F1S1F1F1F10S F1F1F1S1F1F1F10, respectively?

Accepted Answer

A) (F1F1F1S1F1F1F10, F1F1F1S1F1F1F10) 
B) (F1F1F1S1F1F1F10, F1F1F1S1F1F1F10) 
C) (F1F1F1S1F1F1F10, F1F1F1S1F1F1F10) 
D) (F1F1F1S1F1F1F10, F1F1F1S1F1F1F10) 
E) Insufficient data is provided to answer this question. 
A) (F1F1F1S1F1F1F10, F1F1F1S1F1F1F10) 
B) (F1F1F1S1F1F1F10, F1F1F1S1F1F1F10) 
C) (F1F1F1S1F1F1F10, F1F1F1S1F1F1F10) 
D) (F1F1F1S1F1F1F10, F1F1F1S1F1F1F10) 
E) Insufficient data is provided to answer this question.

Question 17

Care must be taken when dissolving solid pellets of sodium hydroxide (NaOH) in water, because the temperature of the water can rise dramatically. Taking NaOH as the system, what can you deduce about the signs of the entropy change of the system (F1F1F1S1F1F1F10Ssys) and surroundings (F1F1F1S1F1F1F10Ssurr) from this?

Accepted Answer

A) (F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0 and F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0) 
B) (F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0 and F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0) 
C) (F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0 and F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0) 
D) (F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0 and F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0) 
E) Nothing can be deduced from this limited information. 
A) (F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0 and F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0) 
B) (F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0 and F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0) 
C) (F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0 and F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0) 
D) (F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0 and F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0) 
E) Nothing can be deduced from this limited information.

Question 18

In an experiment, 1.00 atm of N2(g) in a 10.0 L container at 25F1F1F1S1F1F1F10C was reacted under standard state conditions with a stoichiometric quantity of H2(g) to form ammonia:   . What is the entropy change for the reaction?

Accepted Answer

A) (F1F1F1S1F1F1F10198.7 J/K) 
B) (F1F1F1S1F1F1F1081.5 J/K) 
C) (F1F1F1S1F1F1F1027.2 J/K) 
D) (F1F1F1S1F1F1F1081.5 J/K) 
E) (F1F1F1S1F1F1F10198.7 J/K) 
A) (F1F1F1S1F1F1F10198.7 J/K) 
B) (F1F1F1S1F1F1F1081.5 J/K) 
C) (F1F1F1S1F1F1F1027.2 J/K) 
D) (F1F1F1S1F1F1F1081.5 J/K) 
E) (F1F1F1S1F1F1F10198.7 J/K)

Question 19

Because the triple point of water is 273 K, what must be true of the change in enthalpy and the change in entropy for ice converting to water at this temperature?

Accepted Answer

A) (F1F1F1S1F1F1F10H/F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 273 K) 
B) (F1F1F1S1F1F1F10S/F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 273 K) 
C) (F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 273 K) 
D) (F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 273 K 
E) (F1F1F1S1F1F1F10H )(F1F1F1S1F1F1F10S ) F1F1F1S1F1F1F10 273 K) 
A) (F1F1F1S1F1F1F10H/F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 273 K) 
B) (F1F1F1S1F1F1F10S/F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 273 K) 
C) (F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 273 K) 
D) (F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 273 K 
E) (F1F1F1S1F1F1F10H )(F1F1F1S1F1F1F10S ) F1F1F1S1F1F1F10 273 K)

Question 20

Given the following two measurements of the equilibrium constant for a reaction, calculate F1F1F1S1F1F1F10HF1F1F1S1F1F1F10 for the reaction.

Accepted Answer

A) 255 kJ/mol 
B) (F1F1F1S1F1F1F10271 kJ/mol) 
C) 3,250 kJ/mol 
D) (F1F1F1S1F1F1F103,250 kJ/mol) 
E) (F1F1F1S1F1F1F10271 kJ/mol) 
A) 255 kJ/mol 
B) (F1F1F1S1F1F1F10271 kJ/mol) 
C) 3,250 kJ/mol 
D) (F1F1F1S1F1F1F103,250 kJ/mol) 
E) (F1F1F1S1F1F1F10271 kJ/mol)

Exam 17: Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

If  for a reaction is 2.03 kJ/mol, what is K for the reaction at 300 K?

Indicate which of the following has the largest standard molar entropy (S ).

The entropy of fusion for ice at 0C and 1 atm is 22 J/mol  K. How many joules of heat are required to melt a typical ice cube at 0C and 1 atm? Assume an ice cube is about 1 oz or 28 g.

The equilibrium constant for a given reaction ________

Determine the entropy change for the reaction given the following information:

Which of the following is/are true for a reversible process at equilibrium? I. Suniv  0 II. Ssys  0 III. Gsys  0

What is the standard entropy change when 10.0 g of methane reacts with 10.0 g of oxygen?

Calculate the equilibrium constant at 500 K for the following reaction given the data below: N2(g)  3H2(g) 2NH3(g) Kc (298 K)  6.1  105 (NH3, g)  16.5 kJ/mol (NH3, g)  46.1 kJ/mol

Before class, students were seated at three tables. When the school alarm went off suddenly, all the students distributed throughout the room to collect their belongings. The entropy of the class ________

Which statement about the reaction below, where en  ethylenediamine (H2NCH2CH2NH2), is not correct?

Indicate which one of the following reactions results in a positive Ssys.

Which of the following is in the correct order of standard state entropy? I. diamond  graphite II. liquid water  solid water III. NH3  H2

The symbol  (CH4, g) refers to which of the following reactions?

A sketch of the free energy for a hypothetical chemical equilibrium is shown here. What part of the plot on the axis representing the relative quantities of reactants and products corresponds to a value of Q that is less than K?

A reaction is not spontaneous at any temperature. What are the signs for H  and S , respectively?

Care must be taken when dissolving solid pellets of sodium hydroxide (NaOH) in water, because the temperature of the water can rise dramatically. Taking NaOH as the system, what can you deduce about the signs of the entropy change of the system (Ssys) and surroundings (Ssurr) from this?

In an experiment, 1.00 atm of N2(g) in a 10.0 L container at 25C was reacted under standard state conditions with a stoichiometric quantity of H2(g) to form ammonia: . What is the entropy change for the reaction?

Because the triple point of water is 273 K, what must be true of the change in enthalpy and the change in entropy for ice converting to water at this temperature?

Given the following two measurements of the equilibrium constant for a reaction, calculate H for the reaction.

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

Which of the following is/are true for a reversible process at equilibrium? I. S_univ  0 II. S_sys  0 III. G_sys  0

Calculate the equilibrium constant at 500 K for the following reaction given the data below: N₂(g)  3H₂(g) 2NH₃(g) K_c(298 K)  6.1  10⁵ (NH₃, g)  16.5 kJ/mol (NH₃, g)  46.1 kJ/mol

Which statement about the reaction below, where en  ethylenediamine (H₂NCH₂CH₂NH₂), is not correct?

Indicate which one of the following reactions results in a positive S_sys.

Which of the following is in the correct order of standard state entropy? I. diamond  graphite II. liquid water  solid water III. NH₃  H₂

The symbol  (CH₄, g) refers to which of the following reactions?

Care must be taken when dissolving solid pellets of sodium hydroxide (NaOH) in water, because the temperature of the water can rise dramatically. Taking NaOH as the system, what can you deduce about the signs of the entropy change of the system (S_sys) and surroundings (S_surr) from this?

In an experiment, 1.00 atm of N₂(g) in a 10.0 L container at 25C was reacted under standard state conditions with a stoichiometric quantity of H₂(g) to form ammonia: . What is the entropy change for the reaction?