Question 1

For any thermodynamic function Y,ΔY° for a reaction refers to the change in Y for the process in which

Accepted Answer

A) the mixed reactants at 1 atm go to equilibrium at 1 atm. 
B) the separate reactants at 1 atm go to equilibrium at 1 atm. 
C) the separate reactants in their standard states are completely converted to separate products in their standard states. 
D) the spontaneous reaction occurs. 
A) the mixed reactants at 1 atm go to equilibrium at 1 atm. 
B) the separate reactants at 1 atm go to equilibrium at 1 atm. 
C) the separate reactants in their standard states are completely converted to separate products in their standard states. 
D) the spontaneous reaction occurs.

Question 2

Which has the highest standard molar entropy at 25°C?

Accepted Answer

A) F2(g) 
B) Cl2(g) 
C) Br2(g) 
D) I2(g) 
A) F2(g) 
B) Cl2(g) 
C) Br2(g) 
D) I2(g)

Question 3

Predict the sign of ΔS for each of the following processes,which occur at constant temperature.
I.The volume of 2.0 moles of O2(g)increases from 44 L to 52 L.
II.The pressure of 2.0 moles of O2(g)increases from 1.0 atm to 1.2 atm.

Accepted Answer

A) I: ΔS= negative;II: ΔS= negative 
B) I: ΔS= negative;II: ΔS= positive 
C) I: ΔS= positive;II: ΔS= negative 
D) I: ΔS= positive;II: ΔS= positive 
A) I: ΔS= negative;II: ΔS= negative 
B) I: ΔS= negative;II: ΔS= positive 
C) I: ΔS= positive;II: ΔS= negative 
D) I: ΔS= positive;II: ΔS= positive

Question 4

What is the relationship between ΔG,Qp,and Kp for a reaction involving gases?

Accepted Answer

A) ΔG = Qp/Kp 
B) ΔG = Kp/Qp 
C) ΔG = RTln(Qp/Kp) 
D) ΔG = RTln(Kp/Qp) 
A) ΔG = Qp/Kp 
B) ΔG = Kp/Qp 
C) ΔG = RTln(Qp/Kp) 
D) ΔG = RTln(Kp/Qp)

Question 5

Which statement is true concerning the standard states of F2(g)and C6H12O6(aq)?

Accepted Answer

A) The standard state for F2(g)is the pure gas at 1 atm and for C6H12O6(aq)is the pure solid at 1 atm. 
B) The standard state for F2(g)is the pure gas at 1 mol/L and for C6H12O6(aq)is the pure solid at 1 atm. 
C) The standard state for F2(g)is the pure gas at 1 atm and for C6H12O6(aq)is the solution at a concentration of 1 mol/L. 
D) The standard state for F2(g)is the pure gas at 1 mol/L and for C6H12O6(aq)is the solution at a concentration of 1 mol/L. 
A) The standard state for F2(g)is the pure gas at 1 atm and for C6H12O6(aq)is the pure solid at 1 atm. 
B) The standard state for F2(g)is the pure gas at 1 mol/L and for C6H12O6(aq)is the pure solid at 1 atm. 
C) The standard state for F2(g)is the pure gas at 1 atm and for C6H12O6(aq)is the solution at a concentration of 1 mol/L. 
D) The standard state for F2(g)is the pure gas at 1 mol/L and for C6H12O6(aq)is the solution at a concentration of 1 mol/L.

Question 6

If the entropy of a collection of molecules in 5000 boxes is 1.76 × 10-20 J/K,how many molecules are there?

Accepted Answer

Question 7

For a spontaneous process

Accepted Answer

A) energy and entropy are conserved. 
B) energy is conserved and the entropy of the system and surroundings increases. 
C) the energy of the system and the surroundings decreases and the entropy of the system and surroundings increases. 
D) both the energy and the entropy of the system and surroundings decrease. 
A) energy and entropy are conserved. 
B) energy is conserved and the entropy of the system and surroundings increases. 
C) the energy of the system and the surroundings decreases and the entropy of the system and surroundings increases. 
D) both the energy and the entropy of the system and surroundings decrease.

Question 8

If Q increases

Accepted Answer

A) ΔG increases and the reaction becomes more spontaneous. 
B) ΔG increases and the reaction becomes less spontaneous. 
C) ΔG decreases and the reaction becomes more spontaneous. 
D) ΔG decreases and the reaction becomes less spontaneous. 
A) ΔG increases and the reaction becomes more spontaneous. 
B) ΔG increases and the reaction becomes less spontaneous. 
C) ΔG decreases and the reaction becomes more spontaneous. 
D) ΔG decreases and the reaction becomes less spontaneous.

Question 9

Calculate ΔS° for the formation of one mole of solid sodium bromide from the elements at 25°C.

Accepted Answer

A) -116.7 J/K 
B) -81.2 J/K 
C) -40.5 J/K 
D) 86.8 J/K 
A) -116.7 J/K 
B) -81.2 J/K 
C) -40.5 J/K 
D) 86.8 J/K

Question 10

Acetylene,C2H2,has a standard enthalpy of formation,ΔH° = 226.7 kJ/mol,and a standard entropy change for its formation from its elements,ΔS° = 58.8 J/K∙mol.The standard free energy of formation of acetylene is ________ kJ/mol.

Accepted Answer

Question 11

Which of the following gas molecules has the greatest standard molar entropy at 25°C?

Accepted Answer

A) C2H2 
B) CH2CH2 
C) CH3CH3 
D) All have the same entropy. 
A) C2H2 
B) CH2CH2 
C) CH3CH3 
D) All have the same entropy.

Question 12

What is the entropy of 10 molecules in a system of 1000 boxes?

Accepted Answer

The answer of What is the entropy of 10 molecules...

Question 13

The reaction 2 H2O(g)+ CO2(g)→ CH4(g)+ 2 CO2(g)is nonspontaneous at 25°C.The addition of a catalyst will ________ (decrease,increase,not change)the rate of reaction and ________ (decrease,increase,not change)the spontaneity of the reaction.

Accepted Answer

Question 14

Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions.
Reaction 1: C(graphite)+ O2(g)→ CO2(g)
Reaction 2: 2 CO(g)+ O2(g)→ 2 CO2(g)

Accepted Answer

A) ΔS° is positive for both reactions. 
B) ΔS° is positive for reaction 1 but negative for reaction 2. 
C) ΔS° is positive for reaction 2 but negative for reaction 1. 
D) ΔS° is negative for both reactions. 
A) ΔS° is positive for both reactions. 
B) ΔS° is positive for reaction 1 but negative for reaction 2. 
C) ΔS° is positive for reaction 2 but negative for reaction 1. 
D) ΔS° is negative for both reactions.

Question 15

For the reaction N2(g)+ O2(g)→ 2NO(g),ΔH° = 180.4 kJ/mol and ΔS° = 24.9 J/K.Is there a temperature at which the spontaneity of this reaction be changed,either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so,estimate the temperature.

Accepted Answer

This reaction is non

Question 16

Consider the following gas-phase reaction of AS1U1B12S1U1B0 (shaded spheres)and BS1U1B12S1U1B0 (unshaded spheres):
AS1U1B12S1U1B0(g)+ BS1U1B12S1U1B0(g)⇌ 2 AB(g)ΔG ° = +25 kJ  
-Which of the above reaction mixtures is ΔG of reaction = ΔG °?

Accepted Answer

A) (1) 
B) (2) 
C) (3) 
D) (4) 
A) (1) 
B) (2) 
C) (3) 
D) (4)

Question 17

The Boltzmann formula is S = k ln W.A perfect crystal has a molar entropy of 0 at absolute zero because

Accepted Answer

A) W = 0. 
B) W = 1. 
C) W = NA. 
D) k = 1. 
A) W = 0. 
B) W = 1. 
C) W = NA. 
D) k = 1.

Question 18

The reaction A(g)→ B(g)is spontaneous under standard conditions.Which of the following statements must be true?
I.The reaction B(g)→ A(g)is nonspontaneous under standard conditions.
II.A(g)will be completely converted to B(g)if sufficient time is allowed.
III.A(g)will be completely converted to B(g)rapidly.

Accepted Answer

A) none of these 
B) I 
C) I and II 
D) I,II,and III 
A) none of these 
B) I 
C) I and II 
D) I,II,and III

Question 19

Which of the following is zero at 25°C?

Accepted Answer

A) ΔG°f for N2(g) 
B) ΔG°f for H2O (l) 
C) S° for N2 (g) 
D) S° for H2O (l) 
A) ΔG°f for N2(g) 
B) ΔG°f for H2O (l) 
C) S° for N2 (g) 
D) S° for H2O (l)

Question 20

What is the entropy change associated with the expansion of one mole of an ideal gas from an initial volume of V to a final volume of 4.50V at constant temperature?

Accepted Answer

A) ΔS = 4.50 R ln (Vf/Vi) 
B) ΔS = - 4.50 R ln (Vf/Vi) 
C) ΔS = R ln 4.50 
D) ΔS = -R ln 4.50 
A) ΔS = 4.50 R ln (Vf/Vi) 
B) ΔS = - 4.50 R ln (Vf/Vi) 
C) ΔS = R ln 4.50 
D) ΔS = -R ln 4.50

Exam 16: Thermodynamics: Entropy, free Energy, and Equilibrium

For any thermodynamic function Y,ΔY° for a reaction refers to the change in Y for the process in which

Which has the highest standard molar entropy at 25°C?

Predict the sign of ΔS for each of the following processes,which occur at constant temperature. I.The volume of 2.0 moles of O2(g)increases from 44 L to 52 L. II.The pressure of 2.0 moles of O2(g)increases from 1.0 atm to 1.2 atm.

What is the relationship between ΔG,Qp,and Kp for a reaction involving gases?

Which statement is true concerning the standard states of F2(g)and C6H12O6(aq)?

If the entropy of a collection of molecules in 5000 boxes is 1.76 × 10-20 J/K,how many molecules are there?

For a spontaneous process

If Q increases

Calculate ΔS° for the formation of one mole of solid sodium bromide from the elements at 25°C.

Acetylene,C2H2,has a standard enthalpy of formation,ΔH° = 226.7 kJ/mol,and a standard entropy change for its formation from its elements,ΔS° = 58.8 J/K∙mol.The standard free energy of formation of acetylene is ________ kJ/mol.

Which of the following gas molecules has the greatest standard molar entropy at 25°C?

What is the entropy of 10 molecules in a system of 1000 boxes?

The reaction 2 H2O(g)+ CO2(g)→ CH4(g)+ 2 CO2(g)is nonspontaneous at 25°C.The addition of a catalyst will ________ (decrease,increase,not change)the rate of reaction and ________ (decrease,increase,not change)the spontaneity of the reaction.

Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions. Reaction 1: C(graphite)+ O2(g)→ CO2(g) Reaction 2: 2 CO(g)+ O2(g)→ 2 CO2(g)

For the reaction N2(g)+ O2(g)→ 2NO(g),ΔH° = 180.4 kJ/mol and ΔS° = 24.9 J/K.Is there a temperature at which the spontaneity of this reaction be changed,either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so,estimate the temperature.

Consider the following gas-phase reaction of A2 (shaded spheres)and B2 (unshaded spheres): A2(g)+ B2(g)⇌ 2 AB(g)ΔG ° = +25 kJ -Which of the above reaction mixtures is ΔG of reaction = ΔG °?

The Boltzmann formula is S = k ln W.A perfect crystal has a molar entropy of 0 at absolute zero because

Which of the following is zero at 25°C?

What is the entropy change associated with the expansion of one mole of an ideal gas from an initial volume of V to a final volume of 4.50V at constant temperature?

Chemistry: Matter and Measurement

Atoms, molecules, and Ions

Formulas, equations, and Moles

Reactions in Aqueous Solutions

Periodicity and the Atomic Structure of Atoms

Ionic Bonds and Some Main-Group Chemistry

Covalent Bonds and Molecular Structure

Thermochemistry: Chemical Energy

Gases: Their Properties and Behavior

Liquids,solids,and Phase Changes

Solutions and Their Properties

Chemical Kinetics

Chemical Equilibrium

Aqueous Equilibria: Acids and Bases

Applications of Aqueous Equilibria

Electrochemistry

Hydrogen, oxygen, and Water

The Main-Group Elements

Transition Elements and Coordination Chemistry

Metals and Solid-State Materials

Nuclear Chemistry

Organic and Biological Chemistry

Filters

Predict the sign of ΔS for each of the following processes,which occur at constant temperature. I.The volume of 2.0 moles of O₂(g)increases from 44 L to 52 L. II.The pressure of 2.0 moles of O₂(g)increases from 1.0 atm to 1.2 atm.

What is the relationship between ΔG,Q_p,and K_p for a reaction involving gases?

Which statement is true concerning the standard states of F₂(g)and C₆H₁₂O₆(aq)?

If the entropy of a collection of molecules in 5000 boxes is 1.76 × 10^-20 J/K,how many molecules are there?

Acetylene,C₂H₂,has a standard enthalpy of formation,ΔH° = 226.7 kJ/mol,and a standard entropy change for its formation from its elements,ΔS° = 58.8 J/K∙mol.The standard free energy of formation of acetylene is ________ kJ/mol.

The reaction 2 H₂O(g)+ CO₂(g)→ CH₄(g)+ 2 CO₂(g)is nonspontaneous at 25°C.The addition of a catalyst will (decrease,increase,not change)the rate of reaction and (decrease,increase,not change)the spontaneity of the reaction.

Without doing any calculations,determine whether the standard entropy change,ΔS° is positive or negative for each of the following reactions. Reaction 1: C(graphite)+ O₂(g)→ CO₂(g) Reaction 2: 2 CO(g)+ O₂(g)→ 2 CO₂(g)

For the reaction N₂(g)+ O₂(g)→ 2NO(g),ΔH° = 180.4 kJ/mol and ΔS° = 24.9 J/K.Is there a temperature at which the spontaneity of this reaction be changed,either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so,estimate the temperature.

Consider the following gas-phase reaction of A₂ (shaded spheres)and B₂ (unshaded spheres): A₂(g)+ B₂(g)⇌ 2 AB(g)ΔG ° = +25 kJ -Which of the above reaction mixtures is ΔG of reaction = ΔG °?