Question 1

Consider the reaction,3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g) ,where ΔH = -137 kJ. How many kilojoules are released when 92.3 g of NO2 reacts?

Accepted Answer

A)  2.01 kJ are released
B)  2.75 × 102 kJ are released
C)  91.6 kJ are released
D)  1.26 × 104 kJ are releasedE) C) and D)
F) A) and B)

Question 2

When the pressure of a reaction at equilibrium decreases,in which direction does the equilibrium shift?

Accepted Answer

A)  The equilibrium shifts in the direction that increases the number of moles of gas.
B)  The equilibrium shifts in the direction that decreases the number of moles of gas.
C)  The equilibrium does not shift.
D)  The equilibrium shifts always shifts to the right.
E)  The equilibrium shifts always shifts to the left.F) None of the above
G) C) and D)

Question 3

In order to cause an endothermic equilibrium reaction to shift in a direction to form more products,the reaction must be heated.

Accepted Answer

A) True 
 B)False

Question 4

The equilibrium constant expression for the reversible reaction: CHCl3(g)+ 3 HCl(g)  CH4(g)+ 3 Cl2(g)is  .

Accepted Answer

A) True 
 B)False

Question 5

Consider the reversible reaction at equilibrium: N2(g) + O2(g)  2(g) + O2(g)    2 NO(g) . What is the effect of removing some N2(g) from the equilibrium system? A) The concentration of O2(g) increases B) The concentration of O2(g) decreases C) The concentration of NO(g) increases D) The equilibrium system shifts to the right" class="answers-bank-image d-inline" rel="preload" > 2 NO(g) . What is the effect of removing some N2(g) from the equilibrium system?

Accepted Answer

A)  The concentration of O2(g) increases
B)  The concentration of O2(g) decreases
C)  The concentration of NO(g) increases
D)  The equilibrium system shifts to the rightE) C) and D)
F) B) and D)

Question 6

Heat is absorbed in an ________ reaction.

Accepted Answer

The answer of Heat is absorbed in an ________ reaction....

Question 7

Le Châtelier's principle is a general rule used to explain the effect of a change in reaction conditions on equilibrium.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following is ALWAYS necessary for a chemical reaction to occur between two reactants,A and B?

Accepted Answer

A)  Equal amounts of A and B must be present
B)  A and B must be present in the same physical state
C)  The reaction must be carried out at a temperature higher than room temperature
D)  A and B must collide with the proper orientation and with a certain minimum amount of energyE) A) and B)
F) None of the above

Question 9

The reversible reaction: PCl3(g) + Cl2(g)  3(g) + Cl2(g)    PCl5(g) ,has K = 0.5. Based on the molecular art shown below,what can be inferred about the reaction conditions?   A) The reaction has not yet reached equilibrium. B) The reaction mixture is at equilibrium. C) The reaction will shift to the left to reach equilibrium. D) The forward reaction is favorable." class="answers-bank-image d-inline" rel="preload" > PCl5(g) ,has K = 0.5. Based on the molecular art shown below,what can be inferred about the reaction conditions? 3(g) + Cl2(g)    PCl5(g) ,has K = 0.5. Based on the molecular art shown below,what can be inferred about the reaction conditions?   A) The reaction has not yet reached equilibrium. B) The reaction mixture is at equilibrium. C) The reaction will shift to the left to reach equilibrium. D) The forward reaction is favorable." class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  The reaction has not yet reached equilibrium.
B)  The reaction mixture is at equilibrium.
C)  The reaction will shift to the left to reach equilibrium.
D)  The forward reaction is favorable.E) A) and B)
F) A) and C)

Question 10

Changes in potential energy occur in chemical reactions.

Accepted Answer

A) True 
 B)False

Question 11

Bond dissociation energies are always positive numbers.

Accepted Answer

A) True 
 B)False

Question 12

When reactants can come together and form products,and products can come together to re-form reactants,the reaction is called a ________ reaction.

Accepted Answer

The answer of When reactants can come together and form...

Question 13

A reversible reaction in which K = 9.65 × 10-14 contains a negligible amount of reactants at equilibrium.

Accepted Answer

A) True 
 B)False

Question 14

One step in the metabolism of glucose is depicted below. Which statement best describes how the equilibrium system would respond if the amount of dihydroxyacetone phosphate is decreased?

Accepted Answer

A)  The system would shift to the left,consuming more dihydroxyacetone phosphate.
B)  The system would shift to the right,producing more dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.
C)  The system would shift to the left,producing more fructose 1,6-bisphosphate.
D)  The system would shift to the right,consuming some glyceraldehyde 3-phosphate and producing more dihydroxyacetone phosphate.E) B) and D)
F) All of the above

Question 15

Once equilibrium is reached in a chemical reaction,reactants stop forming products.

Accepted Answer

A) True 
 B)False

Question 16

When the equilibrium constant for a reaction is much less than one (K < 1),the concentration of the products is larger than the concentration of the reactants.

Accepted Answer

A) True 
 B)False

Question 17

An equilibrium constant with a value of 8.0 × 106 indicates that at equilibrium ________.

Accepted Answer

A)  the reactants are favored
B)  the products are favored
C)  approximately equal concentrations of reactants and products are present
D)  there are more reactants present than productsE) A) and D)
F) B) and C)

Question 18

The ΔH for the reaction depicted by the energy diagram below is ________.

Accepted Answer

The answer of The ΔH for the reaction depicted by...

Question 19

A chemical reaction requires 31.39 kJ. How many kilocalories does this correspond to?

Accepted Answer

A)  7,502 kcal
B)  7.502 kcal
C)  131.3 kcal
D)  0.1313 kcal
E)  31.39 kcalF) B) and E)
G) All of the above

Question 20

Bond breaking is endothermic.

Accepted Answer

A) True 
 B)False

Exam 6: Energy Changes,reaction Rates,and Equilibrium

A reversible reaction in which K = 9.65 × 10-14 contains a negligible amount of reactants at equilibrium.

Correct AnswerverifiedShow Answer

Bond dissociation energies are always positive numbers.

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Heat is absorbed in an ________ reaction.

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The equilibrium constant expression for the reversible reaction: CHCl3(g)+ 3 HCl(g) CH4(g)+ 3 Cl2(g)is .

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Bond breaking is endothermic.

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The ΔH for the reaction depicted by the energy diagram below is ________.

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Consider the reversible reaction at equilibrium: N2(g) + O2(g) 2 NO(g) . What is the effect of removing some N2(g) from the equilibrium system?

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An equilibrium constant with a value of 8.0 × 106 indicates that at equilibrium ________.

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When reactants can come together and form products,and products can come together to re-form reactants,the reaction is called a ________ reaction.

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Which of the following is ALWAYS necessary for a chemical reaction to occur between two reactants,A and B?

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Consider the reaction,3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g) ,where ΔH = -137 kJ. How many kilojoules are released when 92.3 g of NO2 reacts?

Correct AnswerverifiedShow Answer

When the pressure of a reaction at equilibrium decreases,in which direction does the equilibrium shift?

Correct AnswerverifiedShow Answer

The reversible reaction: PCl3(g) + Cl2(g) PCl5(g) ,has K = 0.5. Based on the molecular art shown below,what can be inferred about the reaction conditions?

Correct AnswerverifiedShow Answer

Once equilibrium is reached in a chemical reaction,reactants stop forming products.

Correct AnswerverifiedShow Answer

Le Châtelier's principle is a general rule used to explain the effect of a change in reaction conditions on equilibrium.

Correct AnswerverifiedShow Answer

Changes in potential energy occur in chemical reactions.

Correct AnswerverifiedShow Answer

When the equilibrium constant for a reaction is much less than one (K < 1),the concentration of the products is larger than the concentration of the reactants.

Correct AnswerverifiedShow Answer

One step in the metabolism of glucose is depicted below. Which statement best describes how the equilibrium system would respond if the amount of dihydroxyacetone phosphate is decreased?

Correct AnswerverifiedShow Answer

In order to cause an endothermic equilibrium reaction to shift in a direction to form more products,the reaction must be heated.

Correct AnswerverifiedShow Answer

A chemical reaction requires 31.39 kJ. How many kilocalories does this correspond to?

Correct AnswerverifiedShow Answer

A reversible reaction in which K = 9.65 × 10^-14 contains a negligible amount of reactants at equilibrium.

Correct Answer
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The equilibrium constant expression for the reversible reaction: CHCl₃(g)+ 3 HCl(g) CH₄(g)+ 3 Cl₂(g)is .

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Consider the reversible reaction at equilibrium: N₂(g) + O₂(g) 2 NO(g) . What is the effect of removing some N₂(g) from the equilibrium system?

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An equilibrium constant with a value of 8.0 × 10⁶ indicates that at equilibrium ________.

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Consider the reaction,3 NO₂(g) + H₂O(l) → 2 HNO₃(aq) + NO(g) ,where ΔH = -137 kJ. How many kilojoules are released when 92.3 g of NO₂ reacts?

Correct Answer
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The reversible reaction: PCl₃(g) + Cl₂(g) PCl₅(g) ,has K = 0.5. Based on the molecular art shown below,what can be inferred about the reaction conditions?

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