Question 1

Which of the following is the best definition of a microstate as it pertains to entropy on the molecular level?

Accepted Answer

A) the state-for example, solid, liquid, or gas-of a small cluster of atoms or molecules 
B) a property, such as temperature, of a small cluster of atoms and molecules that is independent of how the property was achieved 
C) the set of vibrational, rotational, and translational energy levels in a system 
D) a unique specification of the vibrational, rotational, and translational states of a single molecule in a system 
E) a unique specification of the vibrational, rotational, and translational states of all of the particles in a system 
A) the state-for example, solid, liquid, or gas-of a small cluster of atoms or molecules 
B) a property, such as temperature, of a small cluster of atoms and molecules that is independent of how the property was achieved 
C) the set of vibrational, rotational, and translational energy levels in a system 
D) a unique specification of the vibrational, rotational, and translational states of a single molecule in a system 
E) a unique specification of the vibrational, rotational, and translational states of all of the particles in a system

Question 2

According to the second law of thermodynamics, the change in the entropy of the universe (F1F1F1S1F1F1F10Suniv) during a spontaneous reaction is ________

Accepted Answer

A) zero. 
B) negative. 
C) positive. 
D) less than the change in entropy of the system (F1F1F1S1F1F1F10Ssys). 
E) greater than the change in entropy of the system (F1F1F1S1F1F1F10Ssys). 
A) zero. 
B) negative. 
C) positive. 
D) less than the change in entropy of the system (F1F1F1S1F1F1F10Ssys). 
E) greater than the change in entropy of the system (F1F1F1S1F1F1F10Ssys).

Question 3

Perfect crystals of carbon monoxide (CO) are difficult to prepare because the very small dipole moment allows a few molecules to align in a pattern such as CO OC CO instead of CO CO CO. If such disordered crystals were cooled to 0 K, what would be the value of their absolute entropy?

Accepted Answer

A) (F1F1F1S1F1F1F10 0) 
B) (F1F1F1S1F1F1F10 0) 
C) (F1F1F1S1F1F1F10 0) 
D) (F1F1F1S1F1F1F10 0, F1F1F1S1F1F1F10 0, or F1F1F1S1F1F1F10 0, depending on how carefully it was cooled) 
E) (F1F1F1S1F1F1F10 0 or F1F1F1S1F1F1F10 0, depending on how carefully it was cooled) 
A) (F1F1F1S1F1F1F10 0) 
B) (F1F1F1S1F1F1F10 0) 
C) (F1F1F1S1F1F1F10 0) 
D) (F1F1F1S1F1F1F10 0, F1F1F1S1F1F1F10 0, or F1F1F1S1F1F1F10 0, depending on how carefully it was cooled) 
E) (F1F1F1S1F1F1F10 0 or F1F1F1S1F1F1F10 0, depending on how carefully it was cooled)

Question 4

Which, if any, of statements A-D is not true of entropy?

Accepted Answer

A) It is a measure of the distribution of energy in a system at a specific temperature. 
B) It is a measure of the number of accessible microstates in a pure substance. 
C) It is a property of the universe that increases during a spontaneous process. 
D) It is a property of a system that may increase or decrease during a spontaneous process. 
E) All of the above are true statements. 
A) It is a measure of the distribution of energy in a system at a specific temperature. 
B) It is a measure of the number of accessible microstates in a pure substance. 
C) It is a property of the universe that increases during a spontaneous process. 
D) It is a property of a system that may increase or decrease during a spontaneous process. 
E) All of the above are true statements.

Question 5

If for a given chemical reaction at 298 K, the change in free energy, F1F1F1S1F1F1F10G, is more negative than the change in the standard free energy, F1F1F1S1F1F1F10G F1F1F1S1F1F1F10, then ________

Accepted Answer

A) Q F1F1F1S1F1F1F10 K and product is turning back into reactant. 
B) Q F1F1F1S1F1F1F10 K and more product is being produced. 
C) Q F1F1F1S1F1F1F10 K and product is turning back into reactant. 
D) Q F1F1F1S1F1F1F10 K and more product is being produced. 
E) Q F1F1F1S1F1F1F10 K and the reaction has stopped. 
A) Q F1F1F1S1F1F1F10 K and product is turning back into reactant. 
B) Q F1F1F1S1F1F1F10 K and more product is being produced. 
C) Q F1F1F1S1F1F1F10 K and product is turning back into reactant. 
D) Q F1F1F1S1F1F1F10 K and more product is being produced. 
E) Q F1F1F1S1F1F1F10 K and the reaction has stopped.

Question 6

The values of   F1F1F1S1F1F1F10and   F1F1F1S1F1F1F10are shown for the following equilibrium reaction. What makes the equilibrium constant larger at low temperature?       F1F1F1S1F1F1F10H F1F1F1S1F1F1F10F1F1F1S1F1F1F10 F1F1F1S1F1F1F1058.02 kJ/mol, F1F1F1S1F1F1F10S F1F1F1S1F1F1F10F1F1F1S1F1F1F10176.5 J/mol F1F1F1S1F1F1F10 K

Accepted Answer

A) The negative value of F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 is dominant at all temperatures. 
B) The negative value of F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 is dominant at all temperatures. 
C) The negative value of F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 is combined with the small value of T. 
D) The negative value of F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 is combined with the small value of T. 
A) The negative value of F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 is dominant at all temperatures. 
B) The negative value of F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 is dominant at all temperatures. 
C) The negative value of F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 is combined with the small value of T. 
D) The negative value of F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 is combined with the small value of T.

Question 7

Which statement is true of the ideal gas constant, R, and the Boltzmann constant, kB?

Accepted Answer

A) R/kB F1F1F1S1F1F1F10 Avogadro's number. 
B) They both have units of J F1F1F1S1F1F1F10 molF1F1F1S1F1F1F101 F1F1F1S1F1F1F10 KF1F1F1S1F1F1F101. 
C) kBR F1F1F1S1F1F1F10 Avogadro's number. 
D) kB/R F1F1F1S1F1F1F10 Avogadro's number. 
E) 8.3145 J is not equivalent to 0.082058 L F1F1F1S1F1F1F10 atm. 
A) R/kB F1F1F1S1F1F1F10 Avogadro's number. 
B) They both have units of J F1F1F1S1F1F1F10 molF1F1F1S1F1F1F101 F1F1F1S1F1F1F10 KF1F1F1S1F1F1F101. 
C) kBR F1F1F1S1F1F1F10 Avogadro's number. 
D) kB/R F1F1F1S1F1F1F10 Avogadro's number. 
E) 8.3145 J is not equivalent to 0.082058 L F1F1F1S1F1F1F10 atm.

Question 8

Given the following data, determine the molar free energy of combustion for propane gas, C3H8.   (C3H8, g)F1F1F1S1F1F1F1023.5 kJ/mol   (CO2, g)F1F1F1S1F1F1F10394.4 kJ/mol   (H2O, g)F1F1F1S1F1F1F10105.6 kJ/mol

Accepted Answer

F1F1F1S1F

Question 9

Suppose F1F1F1S1F1F1F10GF1F1F1S1F1F1F10 is 25.0 kJ/mol for a hypothetical reaction in which A converts into B. Which of the following statements describes an equilibrium mixture of A and B?

Accepted Answer

A) Only A is present. 
B) Only B is present. 
C) A and B have equal concentrations. 
D) A has a higher concentration than B. 
E) B has a higher concentration than A. 
A) Only A is present. 
B) Only B is present. 
C) A and B have equal concentrations. 
D) A has a higher concentration than B. 
E) B has a higher concentration than A.

Question 10

If K for a reaction is large, ________

Accepted Answer

A) (F1F1F1S1F1F1F10GF1F1F1S1F1F1F10 is definitely negative.) 
B) (F1F1F1S1F1F1F10GF1F1F1S1F1F1F10 is definitely positive.) 
C) (F1F1F1S1F1F1F10GF1F1F1S1F1F1F10 is equal to zero.) 
D) (F1F1F1S1F1F1F10G is definitely negative.) 
E) (F1F1F1S1F1F1F10G is definitely positive.) 
A) (F1F1F1S1F1F1F10GF1F1F1S1F1F1F10 is definitely negative.) 
B) (F1F1F1S1F1F1F10GF1F1F1S1F1F1F10 is definitely positive.) 
C) (F1F1F1S1F1F1F10GF1F1F1S1F1F1F10 is equal to zero.) 
D) (F1F1F1S1F1F1F10G is definitely negative.) 
E) (F1F1F1S1F1F1F10G is definitely positive.)

Question 11

Hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to form sodium chloride (NaCl) and water. If F1F1F1S1F1F1F10H F1F1F1S1F1F1F10 F1F1F1S1F1F1F10 F1F1F1S1F1F1F1056.13 kJ/mol and F1F1F1S1F1F1F10S F1F1F1S1F1F1F10 F1F1F1S1F1F1F10 79.11 J/mol F1F1F1S1F1F1F10 K, what is the temperature of the reaction if F1F1F1S1F1F1F10G F1F1F1S1F1F1F10 F1F1F1S1F1F1F10 F1F1F1S1F1F1F1080.89 kJ/mol?

Accepted Answer

A) 154F1F1F1S1F1F1F10C 
B) 313F1F1F1S1F1F1F10C 
C) 0.313F1F1F1S1F1F1F10C 
D) 40.0F1F1F1S1F1F1F10C 
E) 75F1F1F1S1F1F1F10C 
A) 154F1F1F1S1F1F1F10C 
B) 313F1F1F1S1F1F1F10C 
C) 0.313F1F1F1S1F1F1F10C 
D) 40.0F1F1F1S1F1F1F10C 
E) 75F1F1F1S1F1F1F10C

Question 12

What type of motion is depicted in the following before-and-after pictures?

Accepted Answer

A) rotational 
B) translational 
C) vibrational 
D) Brownian 
E) all of the above 
A) rotational 
B) translational 
C) vibrational 
D) Brownian 
E) all of the above

Question 13

Alcohols for use as biofuels can be produced from glucose that is obtained from starch and cellulose in plants. Use the information in the table below to determine the temperature range, if any, at which the following reaction is spontaneous.

Accepted Answer

A) Reaction is spontaneous at high temperatures. 
B) Reaction is spontaneous at low temperatures. 
C) Reaction is spontaneous at all temperatures. 
D) Reaction is not spontaneous at any temperature. 
E) Whether the reaction is spontaneous cannot be predicted from the information provided. 
A) Reaction is spontaneous at high temperatures. 
B) Reaction is spontaneous at low temperatures. 
C) Reaction is spontaneous at all temperatures. 
D) Reaction is not spontaneous at any temperature. 
E) Whether the reaction is spontaneous cannot be predicted from the information provided.

Question 14

The enthalpy of fusion for benzene (C6H6) is 127.40 kJ/kg, and its melting point is 5.5F1F1F1S1F1F1F10C. What is the entropy change when 1 mole of benzene melts at 5.5F1F1F1S1F1F1F10C?

Accepted Answer

A) 9.95 kJ/K 
B) 35.7 J/K 
C) 1,809 J/K 
D) 1.81 J/K 
E) 127.40 kJ/K 
A) 9.95 kJ/K 
B) 35.7 J/K 
C) 1,809 J/K 
D) 1.81 J/K 
E) 127.40 kJ/K

Question 15

In a spontaneous process, which of the following always increases?

Accepted Answer

A) the entropy of the system 
B) the entropy of the surroundings 
C) the entropy of the universe 
D) the entropy of the system and the universe 
E) the entropy of the system, the surroundings, and the universe 
A) the entropy of the system 
B) the entropy of the surroundings 
C) the entropy of the universe 
D) the entropy of the system and the universe 
E) the entropy of the system, the surroundings, and the universe

Question 16

A reaction with a low enthalpy of reaction value is spontaneous at high temperature but becomes not spontaneous at low 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

The following figures represent distributions of gas molecules between two containers connected by an open tube. In which figure is the entropy of the system maximized?

Accepted Answer

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

Question 18

Alcohols for use as biofuels can be produced from glucose that is obtained from starch and cellulose in plants. Use the information in the table below to determine the free-energy change and whether or not this reaction is spontaneous at 78F1F1F1S1F1F1F10C, which is the boiling point of an ethanolF1F1F1S1F1F1F10water azeotrope.

Accepted Answer

A) (F1F1F1S1F1F1F106 kJ, spontaneous) 
B) (F1F1F1S1F1F1F1076 kJ, not spontaneous) 
C) (F1F1F1S1F1F1F1076 kJ, spontaneous) 
D) (F1F1F1S1F1F1F10258 kJ, not spontaneous) 
E) (F1F1F1S1F1F1F10258 kJ, spontaneous) 
A) (F1F1F1S1F1F1F106 kJ, spontaneous) 
B) (F1F1F1S1F1F1F1076 kJ, not spontaneous) 
C) (F1F1F1S1F1F1F1076 kJ, spontaneous) 
D) (F1F1F1S1F1F1F10258 kJ, not spontaneous) 
E) (F1F1F1S1F1F1F10258 kJ, spontaneous)

Question 19

For a chemical reaction that is not spontaneous, it is found that F1F1F1S1F1F1F10Ssys F1F1F1S1F1F1F10 0. Which of the following could be true?

Accepted Answer

A) (F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0 and its magnitude is less than F1F1F1S1F1F1F10Ssys.) 
B) (F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0 and its magnitude is less than F1F1F1S1F1F1F10Ssys.) 
C) (F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0 and its magnitude is greater than F1F1F1S1F1F1F10Ssys.) 
D) (F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0 and its magnitude is greater than F1F1F1S1F1F1F10Ssys.) 
E) (F1F1F1S1F1F1F10Suniv F1F1F1S1F1F1F10 0) 
A) (F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0 and its magnitude is less than F1F1F1S1F1F1F10Ssys.) 
B) (F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0 and its magnitude is less than F1F1F1S1F1F1F10Ssys.) 
C) (F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0 and its magnitude is greater than F1F1F1S1F1F1F10Ssys.) 
D) (F1F1F1S1F1F1F10Ssurr F1F1F1S1F1F1F10 0 and its magnitude is greater than F1F1F1S1F1F1F10Ssys.) 
E) (F1F1F1S1F1F1F10Suniv F1F1F1S1F1F1F10 0)

Question 20

What types of motion does a molecule of chlorine have?

Accepted Answer

A) translational, rotational, and vibrational 
B) kinetic energy and potential energy 
C) microstate and macrostate 
D) Boltzmann and non-Boltzmann 
E) all of the above 
A) translational, rotational, and vibrational 
B) kinetic energy and potential energy 
C) microstate and macrostate 
D) Boltzmann and non-Boltzmann 
E) all of the above

Exam 17: Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Which of the following is the best definition of a microstate as it pertains to entropy on the molecular level?

According to the second law of thermodynamics, the change in the entropy of the universe (Suniv) during a spontaneous reaction is ________

Perfect crystals of carbon monoxide (CO) are difficult to prepare because the very small dipole moment allows a few molecules to align in a pattern such as CO OC CO instead of CO CO CO. If such disordered crystals were cooled to 0 K, what would be the value of their absolute entropy?

Which, if any, of statements A-D is not true of entropy?

If for a given chemical reaction at 298 K, the change in free energy, G, is more negative than the change in the standard free energy, G , then ________

The values of and are shown for the following equilibrium reaction. What makes the equilibrium constant larger at low temperature? H  58.02 kJ/mol, S 176.5 J/mol  K

Which statement is true of the ideal gas constant, R, and the Boltzmann constant, kB?

Given the following data, determine the molar free energy of combustion for propane gas, C3H8. (C3H8, g)23.5 kJ/mol (CO2, g)394.4 kJ/mol (H2O, g)105.6 kJ/mol

Suppose G is 25.0 kJ/mol for a hypothetical reaction in which A converts into B. Which of the following statements describes an equilibrium mixture of A and B?

If K for a reaction is large, ________

Hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to form sodium chloride (NaCl) and water. If H   56.13 kJ/mol and S   79.11 J/mol  K, what is the temperature of the reaction if G   80.89 kJ/mol?

What type of motion is depicted in the following before-and-after pictures?

Alcohols for use as biofuels can be produced from glucose that is obtained from starch and cellulose in plants. Use the information in the table below to determine the temperature range, if any, at which the following reaction is spontaneous.

The enthalpy of fusion for benzene (C6H6) is 127.40 kJ/kg, and its melting point is 5.5C. What is the entropy change when 1 mole of benzene melts at 5.5C?

In a spontaneous process, which of the following always increases?

A reaction with a low enthalpy of reaction value is spontaneous at high temperature but becomes not spontaneous at low temperature. What are the signs for H  and S , respectively?

The following figures represent distributions of gas molecules between two containers connected by an open tube. In which figure is the entropy of the system maximized?

For a chemical reaction that is not spontaneous, it is found that Ssys  0. Which of the following could be true?

What types of motion does a molecule of chlorine have?

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

According to the second law of thermodynamics, the change in the entropy of the universe (S_univ) during a spontaneous reaction is ________

Which statement is true of the ideal gas constant, R, and the Boltzmann constant, k_B?

Given the following data, determine the molar free energy of combustion for propane gas, C₃H₈. (C₃H₈, g)23.5 kJ/mol (CO₂, g)394.4 kJ/mol (H₂O, g)105.6 kJ/mol

The enthalpy of fusion for benzene (C₆H₆) is 127.40 kJ/kg, and its melting point is 5.5C. What is the entropy change when 1 mole of benzene melts at 5.5C?

For a chemical reaction that is not spontaneous, it is found that S_sys  0. Which of the following could be true?