Deck 18: Entropy Free Energy and Equilibrium

Question 1

What is defined as a process that may occur under a specific set of conditions?

A)Conditional process
B)Nonspontaneous process
C)Specified process
D)Spontaneous process
E)Conditionality law

Answer 1

Spontaneous process

Question 2

A spontaneous endothermic reaction always

A)causes the surroundings to get colder.
B)bursts into flame.
C)requires a spark to initiate it.
D)releases heat to the surroundings.

Answer 2

causes the surroundings to get colder.

Question 3

Which statement is correct?

A)Heating always decreases the entropy of a system.
B)The reaction that results in an increase in the number of moles of gas always decreases the entropy of a system.
C)The greater number of particles leads to a smaller number of microstates.
D)An increase in the temperature decreases all types of molecular motions.
E)The solvation process usually leads to an increase in entropy.

Answer 3

The solvation process usually leads to an increase in entropy.

Question 4

Which,if any,of the following processes is spontaneous under the specified conditions?

A)H₂O(l)→ H₂O(s)at 25°C,1 atm pressure
B)CO₂(s)→ CO₂(g)at 0°C,1 atm pressure
C)2H₂O(g)→ 2H₂(g)+ O₂(g)at 25°C,1 atm pressure
D)C(graphite)→ C(diamond)at 25°C,1 atm pressure
E)None of these processes is spontaneous.

Question 5

How many types of vibrations does a bent triatomic molecule exhibit?

A)0
B)1
C)2
D)3
E)4

Question 6

According to which scientific law does the entropy of the universe increase in spontaneous processes and remain unchanged in equilibrium processes?

A)1^st law of thermodynamics
B)1^st law of entropy
C)1^st universal law
D)2^nd law of thermodynamics
E)3^rd law of thermodynamics

Question 7

If a certain process has ΔS_univ > 0 at 25°C,the process may be described as

A)exothermic.
B)endothermic.
C)spontaneous.
D)moving rapidly toward equilibrium.
E)violating the second law of thermodynamics.

Question 8

Which response includes all of the following processes that are accompanied by an increase in entropy? 1.I₂(s)→ I₂(g)
2)2I(g)→ I₂(g)
3)2NH₃(g)→ N₂(g)+ 3H₂(g)
4)Mg²⁺(aq)+ 2OH^-(aq)→ Mg(OH)₂(s)

A)1,2
B)1,3
C)3,4
D)3
E)2,4

Question 9

How many types of rotations does a bent triatomic molecule exhibit?

A)0
B)1
C)2
D)3
E)4

Question 10

Which of these species has the highest entropy (S°)at 25°C?

A)CH₃OH(l)
B)CO(g)
C)MgCO₃(s)
D)H₂O(l)
E)Si(s)

Question 11

How many types of vibrations does a diatomic molecule exhibit?

A)0
B)1
C)2
D)3
E)4

Question 12

What is defined as a measure of the randomness or disorder of a system?

A)Gibbs free energy
B)Entropy
C)Spontaneous process
D)Nonspontaneous process
E)Enthalpy

Question 13

Which has the largest entropy?

A)C (diamond)
B)C (graphite)
C)H₂O(l)
D)F₂(l)
E)O₂(g)

Question 14

Which of the following is an example of a nonspontaneous process?

A)Ice melting at room temperature
B)Sodium metal reacting violently with water
C)Rusting of iron at room temperature
D)A ball rolling downhill
E)Water freezing at room temperature

Question 15

What is defined as the measure of accessible energy levels of a substance at 1 atm?

A)Atmospheric disorder
B)Atmospheric pressure
C)Atmospheric entropy
D)Specific pressure
E)Standard entropy

Question 16

How many types of rotations does a diatomic molecule exhibit?

A)0
B)1
C)2
D)3
E)4

Question 17

Which statement is correct?

A)The standard entropy of a gas phase substance is less than the standard entropy of the same substance in the solid phase.
B)For two different substances in the same phase,the substance with the more complex structure has the lower entropy.
C)The more highly ordered allotrope of an element has a higher entropy.
D)The entropies of elements and compounds are always positive.
E)For a monatomic gas,the gas with the lower molar mass has the greater entropy.

Question 18

The most probable state is the one with the _______.

A)highest energy
B)largest number of possible arrangements
C)lowest number of possible arrangements
D)most symmetry
E)highest enthalpy

Question 19

Which is a statement of the second law of thermodynamics?

A)The energy of the universe is constant.
B)The entropy of the universe is constant.
C)The enthalpy of the universe is constant.
D)The energy of the universe is decreasing.
E)The entropy of the universe is increasing.

Question 20

When a sky diver free-falls through the air,the process is

A)nonspontaneous because he is accelerating due to the force applied by gravity.
B)nonspontaneous because he is losing potential energy.
C)nonspontaneous because he had planned the jump for two weeks.
D)spontaneous.
E)in equilibrium.

Question 21

A negative sign for ΔG indicates that,at constant T and P,

A)the reaction is exothermic.
B)the reaction is endothermic.
C)the reaction is fast.
D)the reaction is spontaneous.
E)ΔS of the system must be greater than zero.

Question 22

HI has a normal boiling point of -35.4°C,and its ΔH_vap is 21.16 kJ/mol.What is the molar entropy of vaporization (ΔS_vap)of HI?

A)598 J/K • mol
B)68.6 J/K • mol
C)75.2 J/K • mol
D)0.068 J/K • mol
E)89.0 J/K • mol

Question 23

Which species will have the greatest absolute entropy at 25°C?

A)Ne(g)
B)C₂H₂(g)
C)H₂O(l)
D)C₂H₅OH(l)
E)C₄H₁₀(g)

Question 24

Which of the following has ΔG°_f = 0 at 25°C?

A)H₂O(l)
B)H₂O(g)
C)Na(s)
D)O₃(g)
E)O(g)

Question 25

Which of the following will decrease the entropy of an inert gas system?

A)Increasing the temperature
B)Decreasing the volume
C)Adding a different inert gas to the system
D)Increasing the molar mass
E)Decreasing the pressure

Question 26

Which is a statement of the third law of thermodynamics?

A)The entropy of the universe is increasing.
B)The entropy of the universe is constant.
C)For a perfect crystalline solid,the entropy at T = 0 K is zero.
D)The energy of the universe is constant.
E)The entropy of all elements are zero.

Question 27

Which is always true for an exothermic process?

A)q_sys > 0,ΔS_surr < 0
B)q_sys < 0,ΔS_surr > 0
C)q_sys < 0,ΔS_surr < 0
D)q_sys > 0,ΔS_surr > 0
E)w < 0

Question 28

What term is given to the fact that the entropy of a perfect crystalline solid is zero at absolute zero?

A)1st law of thermodynamics
B)2nd law of thermodynamics
C)3rd law of thermodynamics
D)crystalline lattice theory
E)absolute crystallinity

Question 29

Hydrogen sulfide decomposes according to the following reaction: 2 H₂S(g)→ 2H₂ (g)+ S₂(g)
For this reaction at 298 K,ΔS°_rxn = 78.1 J/K • mol,ΔH°_rxn = 169.4 kJ/mol,and ΔG°_rxn = 146.1 kJ/mol.What is ΔG°_rxn at 900.K?

A)-69881 kJ/mol
B)48.4 kJ/mol
C)99.1 kJ/mol
D)240 kJ/mol
E)441 kJ/mol

Question 30

Which of the following results in a decrease in the entropy of the system?

A)O₂(g),300 K → O₂(g),400 K
B)H₂O(s),0°C → H₂O(l),0°C
C)N₂(g),25°C → N₂(aq),25°C
D)NH₃(l),-34.5°C → NH₃(g),-34.5°C
E)2H₂O₂(g)→ 2H₂O(g)+ O₂(g)

Question 31

Which species will have the lowest absolute entropy at 25°C?

A)C₂H₅OH(l)
B)C₂H₂(g)
C)C₃H₈(g)
D)C₃H₇OH(l)
E)C₂H₆(g)

Question 32

Which is the thermodynamic condition for a spontaneous process at constant T and P?

A)ΔS > 0
B)ΔS < 0
C)ΔG < 0
D)ΔG > 0
E)ΔG° = 0

Question 33

Which reaction has the largest ΔS°?

A)2N₂H₄(g)→ 2NH₃(g)+ H₂(g)
B)O₂(g)+ 2H₂(g)→ 2H₂O(l)
C)O₂(g)+ 2H₂(g)→ 2H₂O(g)
D)N₂(g)+ 3H₂(g)→ 2NH₃(g)
E)2NO(g)→ N₂O₂(g)

Question 34

At constant temperature and pressure,which is the correct relationship between ΔG and other thermodynamic quantities?

A)ΔG = ΔH - TΔS
B)ΔG = ΔH + TΔS
C)ΔG = ΔU - TΔS
D)ΔG = -TΔS
E)ΔG = q/T

Question 35

Sodium carbonate can be made by heating sodium bicarbonate: 2NaHCO₃(s)→ Na₂CO₃(s)+ CO₂(g)+ H₂O(g)
At 25°C,for this reaction,ΔH°_rxn = 128.9 kJ/mol and ΔG°_rxn = 33.1 kJ/mol.Above what minimum temperature will the reaction become spontaneous under standard state conditions?

A)0.4 K
B)3.9 K
C)321 K
D)401 K
E)525 K

Question 36

For a chemical reaction to be spontaneous only at high temperatures,which conditions must be met?

A)ΔS° > 0,ΔH° > 0
B)ΔS° > 0,ΔH° < 0
C)ΔS° < 0,ΔH° < 0
D)ΔS° < 0,ΔH° > 0
E)ΔG° > 0

Question 37

Which is true for a system at equilibrium?

A)ΔS°_sys = ΔS°_surr
B)ΔS°_sys = -ΔS°_surr
C)ΔS°_sys = ΔS°_surr = 0
D)ΔS°_univ > 0
E)ΔS°_univ < 0

Question 38

For a chemical reaction to be spontaneous at all temperatures,which conditions must be met?

A)ΔS°_rxn > 0,ΔH°_rxn > 0
B)ΔS°_rxn > 0,ΔH°_rxn < 0
C)ΔS°_rxn < 0,ΔH°_rxn < 0
D)ΔS°_rxn < 0,ΔH°_rxn > 0
E)ΔS°_rxn = 0,ΔH°_rxn = 0

Question 39

Ozone (O₃)in the atmosphere can react with nitric oxide (NO)as follows. O₃(g)+ NO(g)→ NO₂(g)+ O₂(g).ΔH°_rxn = -199 kJ/mol,ΔS°_rxn = -4.1 J/K • mol
What is ΔG°_rxn for this reaction at 25°C?

A)1020 kJ/mol
B)-1.22 × 103 kJ/mol
C)2.00 × 103 kJ/mol
D)-1.42 × 103 kJ/mol
E)-198 kJ/mol

Question 40

Which is necessary for a process to be spontaneous?

A)ΔH_sys < 0
B)ΔS_sys > 0
C)ΔS_surr < 0
D)ΔS_univ > 0
E)ΔG_sys = 0

Question 41

If an endothermic process is spontaneous when |TΔS| >|ΔH|,then is ΔS is positive,negative,or equal to zero?

Question 42

For the process C₆H₆(l)<-----> C₆H₆(s)at a temperature above the freezing point of C₆H₆,

A)ΔS is positive.
B)ΔH is positive.
C)ΔG is positive.
D)ΔG = O.

Question 43

At temperatures below 273 K,it is observed that liquid water spontaneously freezes to form solid ice.What must be true about the entropy changes of the system and surroundings for this process?

A)ΔS_sys > 0,ΔS_surr > 0
B)ΔS_sys < 0,ΔS_surr > 0
C)ΔS_sys < 0,ΔS_surr < 0
D)ΔS_sys > 0,ΔS_surr < 0
E)ΔS_sys = 0,ΔS_surr > 0

Question 44

What is the third law of thermodynamics?

Question 45

As the molar mass of a compound increases,the entropy ______.

A)decreases
B)is constant
C)increases

Question 46

Is the following process spontaneous?

A)Yes,because ΔH > 0.
B)No,because ΔH < 0.
C)Yes,because ΔS > 0.
D)No,because ΔS < 0.
E)It's impossible to tell without knowing the temperature of the system.

Question 47

Below are energy level diagrams for two different atoms. Based on the diagrams,which atom has the larger standard molar entropy at T = 298 K?

A)Atom 1 has the larger standard molar entropy because the energy of its ground state is larger than the energy of the ground state of atom 2.
B)Atom 2 has the larger standard molar entropy because the energy of its ground state is smaller than the energy of the ground state of atom 1.
C)Atom 1 has the larger standard molar entropy because it has fewer energy levels at lower energy values than atom 2.
D)Atom 2 has the larger standard molar entropy because it has more energy levels at lower energy values than atom 1.
E)Both atoms have the same value of the standard molar entropy at T = 298 K.

Question 48

Which statement is correct?

A)Oxygen is formed during the metabolism of food.
B)The metabolism process results in a positive ΔGo.
C)ADP is hydrolyzed to ATP and phosphoric acid in the body.
D)A protein is a polymer made of carbohydrate units.
E)ATP functions to store energy until it is needed by the body.

Question 49

Which thermodynamical property is a measure of the disorder in the system?

Question 50

Which of the following substances has the greatest entropy per mole?

A)O₂(g)
B)N₂(g)
C)CO(g)
D)CO₂(g)
E)C₄H₁₀(g)

Question 51

The absolute standard entropy of atom X(g)is 100 J/K • mol.Which is a reasonable value for the absolute standard entropy of X₂(g)?

A)200 J/K • mol
B)170 J/K • mol
C)100 J/K • mol
D)80 J/K • mol
E)50 J/K • mol

Question 52

Which statement is correct?

A)Reaction of ADP and alanine results in ATP in the body.
B)A positive ΔG° value means that the reaction is not product favored.
C)CO₂ is released when ADP reacts with an amino acid.
D)Phosphoric acid is one of the products of the reaction of ADP with alanine.
E)Hydrolysis of ATP requires NaOH.

Question 53

How does the entropy change when a solid is melted?

Question 54

Predict the sign of ΔS for the reaction O₂(g)→ 2O(g).

Question 55

How does the entropy change when a gas is liquified?

Question 56

State the second and third laws of thermodynamics.

Question 57

Predict the sign of ΔS for the reaction 6CO₂(g)+ 6H₂O(g)→ C₆H₁₂O₆(s)+ 6O₂(g).

Question 58

The heat of vaporization of 1-pentanol is 55.5 kJ/mol,and its entropy of vaporization is 148 J/K•mol.What is the approximate boiling point of 1-pentanol?

A)100^oC
B)375 ^oC
C)0 ^oC
D)25 ^oC

Question 59

In 1774 Joseph Priestly prepared oxygen by heating mercury(II)oxide according to the reaction HgO(l)<----> Hg(l)+ ½O₂(g),for which rH^o = 90.84 kJ/mol and ΔS^o = 108 J/K.mol.Which of the following statements is true for this reaction?

A)The reaction is spontaneous only at low temperatures.
B)The reaction is spontaneous at all temperatures.
C)ΔG^o becomes less favorable as temperature increases.
D)The reaction is spontaneous only at high temperatures.
E)The reaction is at equilibrium at 25^oC and 1 atm pressure.

Question 60

a.Explain what is meant by a spontaneous process.
b.Is a spontaneous process necessarily a rapid one? Explain,and provide a real reaction as an example to illustrate your answer.

Question 61

The complete combustion of liquid benzene is represented by the equation:
C₆H₆(l)+ 7 O₂(g)→ 6CO₂(g)+ 3H₂O(l)
Using the data below,calculate,for this reaction
a.ΔH°
b.ΔG° at 25°C.