Question 1

Which of the following processes involve an increase in entropy of the system?
I.Mothballs vaporize in a closet.
II.Blocks are assembled into a house.
III.Crystals grow from a sugar solution.
IV.Recyclable plastics are sorted.
V.Cake mix is manufactured from five basic ingredients.

Accepted Answer

A)  II,IV
B)  I,II,III
C)  II,III,IV
D)  I,V
E)  I,III,V

Question 2

Which of the following conditions characterizes a system in a state of chemical equilibrium?

Accepted Answer

A)  Concentrations of reactants and products are equal.
B)  Rate of forward reaction has dropped to zero.
C)  Reactants are being consumed at the same rate they are being produced.
D)  Reactant molecules no longer react with each other.
E)  Product concentrations are greater than reactant concentrations.

Question 3

N2 + O2 → 2 NO ΔH = 43.2 kcal
Based on the reaction shown,which statement is true?

Accepted Answer

A)  43.2 kcal are consumed when 1.00 g of N2 reacts.
B)  43.2 kcal are consumed when 1.00 g of O2 reacts.
C)  43.2 kcal are consumed when 1.00 mole of O2 reacts.
D)  43.2 kcal are produced when 1.00 mole of NO is produced.
E)  43.2 kcal are consumed when 1.00 g of NO is produced.

Question 4

A solid sample at room temperature spontaneously sublimes forming a gas.This change in state is accompanied by which of the changes in the sample?

Accepted Answer

A)  Entropy and energy decrease.
B)  Entropy and energy increase.
C)  Entropy decreases and energy increases.
D)  Entropy increases and energy decreases.

Question 5

For the reaction given below,what quantity of heat will be produced if 90.0 g of C3H8 are consumed in the reaction?
C3H8 + 5 O2 → 3 CO2 + 4 H2O + 488 kcal

Accepted Answer

A)  996 kcal
B)  488 kcal
C)  332 kcal
D)  239 kcal
E)  976 kcal

Question 6

If heat is consumed during a reaction,the reaction is said to be ________.

Accepted Answer

A)  endothermic
B)  exothermic
C)  endergonic
D)  exothermic.
E)  can't tell.

Question 7

If we add a catalyst to the following equation,CO + H2O + heat 2O + heat   CO2 + H2,which way will the equilibrium shift? A) to the left B) no effect C) to the right D) not enough information" class="answers-bank-image d-inline" rel="preload" >
CO2 + H2,which way will the equilibrium shift?

Accepted Answer

A)  to the left
B)  no effect
C)  to the right
D)  not enough information

Question 8

Select the correct figure to match the description.
-A fast reaction with a small positive free energy change

Accepted Answer

A)  
B)  
C)  
D)  
E)

Question 9

2 SO2 (g) + O2 (g)  2 (g) + O2 (g)    2 SO3 (g) + heat K = 4.8 × 1027 Which statement about this system is not true? A) At equilibrium SO3 is the predominant substance. B) Heating the system will cause breakdown of SO3. C) Adding SO2 will cause an increase in the amount of SO3. D) Removing O2 will cause an increase in the amount of SO3. E) The large value of K means that the reaction essentially goes to completion." class="answers-bank-image d-inline" rel="preload" >
2 SO3 (g) + heat K = 4.8 × 1027
Which statement about this system is not true?

Accepted Answer

A)  At equilibrium SO3 is the predominant substance.
B)  Heating the system will cause breakdown of SO3.
C)  Adding SO2 will cause an increase in the amount of SO3.
D)  Removing O2 will cause an increase in the amount of SO3.
E)  The large value of K means that the reaction essentially goes to completion.

Question 10

Match the following.
-A process or reaction that has a positive value of ΔG

Accepted Answer

A)  exergonic
B)  endergonic
C)  exothermic
D)  endothermic
E)  activation energyF) chemical equilibrium

Question 11

Calculate the equilibrium constant for the reaction below if a tank was found to contain 0.106 M O2,0.00652 M SO3 and 0.00129 M SO2.
2 SO3 (g)  2,0.00652 M SO3 and 0.00129 M SO2. 2 SO3 (g)    2 SO2 (g) + O2 (g)  A) 6.78 × 10-2 B) 1.34 × 10-2 C) 4.15 × 10-3 D) 4.35 × 10-2" class="answers-bank-image d-inline" rel="preload" >
2 SO2 (g) + O2 (g)

Accepted Answer

A)  6.78 × 10-2
B)  1.34 × 10-2
C)  4.15 × 10-3
D)  4.35 × 10-2

Question 12

A reaction which is unfavorable with respect to entropy,but favorable with respect to enthalpy

Accepted Answer

A)  could occur at any temperature.
B)  could not occur regardless of temperature.
C)  could occur at low temperatures but not at higher temperatures.
D)  could occur at high temperatures but not at lower temperatures.
E)  none of the above

Question 13

-In the reaction energy diagrams shown,reaction A is ________,and it occurs ________ reaction B.

Accepted Answer

A)  endergonic; faster than
B)  exergonic; faster than
C)  endergonic; slower than
D)  exergonic; slower than
E)  exergonic; at the same rate as

Question 14

Which process is not likely to be considered reversible?

Accepted Answer

A)  a round trip to Las Vegas
B)  melting wax to make candles
C)  a reaction using the symbol "↔"
D)  cutting down a tree
E)  dissolving salt in water

Question 15

All of the statements regarding the symbol "ΔH" are correct except

Accepted Answer

A)  it represents the difference between the energy used in breaking bonds and the energy released in forming bonds in a chemical reaction.
B)  it can be called heat of reaction.
C)  it can be called enthalpy change.
D)  it can be called entropy change.
E)  it has a negative value for an exothermic reaction.

Question 16

A reaction that is spontaneous can be described as

Accepted Answer

A)  proceeding in both the forward and reverse directions.
B)  having the same rate in both the forward and reverse directions.
C)  releasing heat to the surroundings.
D)  proceeding without external influence once it has begun.
E)  increasing in disorder.

Question 17

Activation energy can best be described as

Accepted Answer

A)  the energy level of the products.
B)  the maximum energy level of the reaction.
C)  the energy level of the reactants.
D)  the difference in energy between reactants and products.
E)  the difference in energy between reactants and the maximum energy.

Question 18

Consider the reaction:
A + 2 B 
2 C + D
The equilibrium expression for this reaction is:

Accepted Answer

A)  
B)  
C)  
D)  
E)

Question 19

Match the following.
-A state in which the rate of the forward reaction is exactly equal to the rate of the reverse reaction

Accepted Answer

A)  exergonic
B)  endergonic
C)  exothermic
D)  endothermic
E)  activation energyF) chemical equilibrium

Question 20

P4 (s) + 10 Cl2 (g) → 4 PCl5 (s)  ΔH = -435.2 kcal
Based on the reaction shown,which statement is true?

Accepted Answer

A)  When 1 mol P4 (s) reacts,435.2 kcal are released.
B)  When 1 mol PCl5 (s) is produced,435.2 kcal are released.
C)  When 30.97 g P4 (s) react,435.2 kcal are released.
D)  When 123.88 g P4 (s) react,435.2 kcal are consumed.
E)  When 208.22 g PCl5 (s) are produced,435.2 kcal are consumed.

Exam 7: Chemical Reactions: Energy, rates, and Equilibrium

N2 + O2 → 2 NO ΔH = 43.2 kcal Based on the reaction shown,which statement is true?

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Calculate the equilibrium constant for the reaction below if a tank was found to contain 0.106 M O2,0.00652 M SO3 and 0.00129 M SO2. 2 SO3 (g) 2 SO2 (g) + O2 (g)

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If we add a catalyst to the following equation,CO + H2O + heat CO2 + H2,which way will the equilibrium shift?

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Select the correct figure to match the description. -A fast reaction with a small positive free energy change

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Which of the following processes involve an increase in entropy of the system? I.Mothballs vaporize in a closet. II.Blocks are assembled into a house. III.Crystals grow from a sugar solution. IV.Recyclable plastics are sorted. V.Cake mix is manufactured from five basic ingredients.

Correct AnswerverifiedShow Answer

For the reaction given below,what quantity of heat will be produced if 90.0 g of C3H8 are consumed in the reaction? C3H8 + 5 O2 → 3 CO2 + 4 H2O + 488 kcal

Correct AnswerverifiedShow Answer

A solid sample at room temperature spontaneously sublimes forming a gas.This change in state is accompanied by which of the changes in the sample?

Correct AnswerverifiedShow Answer

A reaction which is unfavorable with respect to entropy,but favorable with respect to enthalpy

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Which process is not likely to be considered reversible?

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Match the following. -A state in which the rate of the forward reaction is exactly equal to the rate of the reverse reaction

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Match the following. -A process or reaction that has a positive value of ΔG

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2 SO2 (g) + O2 (g) 2 SO3 (g) + heat K = 4.8 × 1027 Which statement about this system is not true?

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A reaction that is spontaneous can be described as

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If heat is consumed during a reaction,the reaction is said to be ________.

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Consider the reaction: A + 2 B 2 C + D The equilibrium expression for this reaction is:

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All of the statements regarding the symbol "ΔH" are correct except

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-In the reaction energy diagrams shown,reaction A is ________,and it occurs ________ reaction B.

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Activation energy can best be described as

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Which of the following conditions characterizes a system in a state of chemical equilibrium?

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P4 (s) + 10 Cl2 (g) → 4 PCl5 (s) ΔH = -435.2 kcal Based on the reaction shown,which statement is true?

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N₂ + O₂ → 2 NO ΔH = 43.2 kcal Based on the reaction shown,which statement is true?

Correct Answer
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Calculate the equilibrium constant for the reaction below if a tank was found to contain 0.106 M O₂,0.00652 M SO₃ and 0.00129 M SO₂. 2 SO₃ (g) 2 SO₂ (g) + O₂ (g)

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If we add a catalyst to the following equation,CO + H₂O + heat CO₂ + H₂,which way will the equilibrium shift?

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For the reaction given below,what quantity of heat will be produced if 90.0 g of C₃H₈ are consumed in the reaction? C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O + 488 kcal

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2 SO₂ (g) + O₂ (g) 2 SO₃ (g) + heat K = 4.8 × 10²⁷ Which statement about this system is not true?

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-In the reaction energy diagrams shown,reaction A is ,and it occurs reaction B.

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P₄ (s) + 10 Cl₂ (g) → 4 PCl₅(s) ΔH = -435.2 kcal Based on the reaction shown,which statement is true?

Correct Answer
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