Question 1

According to Le Chatelier's principle, which of the following effects will occur if NH3 is removed from an equilibrium mixture governed by the equation:

Accepted Answer

A)  Concentration of N2 will increase. 
B)  Heat will be generated. 
C)  Concentration of H2 will decrease. 
D)  More than one correct response. 
E)  No correct response. 
A)  Concentration of N2 will increase. 
B)  Heat will be generated. 
C)  Concentration of H2 will decrease. 
D)  More than one correct response. 
E)  No correct response. D

Question 2

Le Chatelier's principle states that:

Accepted Answer

A)  Only exothermic reactions can reach chemical equilibrium. 
B)  Only reactions in which a catalyst is present can reach chemical equilibrium. 
C)  If a chemical equilibrium is disturbed, the system will try and reestablish equilibrium. 
D)  If a chemical equilibrium is disturbed, the temperature of the system will always decrease. 
A)  Only exothermic reactions can reach chemical equilibrium. 
B)  Only reactions in which a catalyst is present can reach chemical equilibrium. 
C)  If a chemical equilibrium is disturbed, the system will try and reestablish equilibrium. 
D)  If a chemical equilibrium is disturbed, the temperature of the system will always decrease. C

Question 3

For the indicated element, select the correct oxidation number from the response list: oxidation number of Cr in Cr2O72-+.

Accepted Answer

A)  +2 
B)  +3 
C)  +4 
D)  +6 
A)  +2 
B)  +3 
C)  +4 
D)  +6 D

Question 4

Consider the following equilibrim:   Determine the effect on the position of equilibrium when the temperature is decreased.

Accepted Answer

A)  shifts to the right 
B)  shifts to the left 
C)  does not shift 
D)  shifts to both the left and the right 
A)  shifts to the right 
B)  shifts to the left 
C)  does not shift 
D)  shifts to both the left and the right

Question 5

Assign the following reaction to one of the reaction classifications given in the response list: 4PH3 + Ni(CO)4 F1F1F1S1F1F1F10 4CO + Ni(PH3)4

Accepted Answer

A)  decomposition 
B)  combination 
C)  displacement 
D)  exchange 
A)  decomposition 
B)  combination 
C)  displacement 
D)  exchange

Question 6

Consider the following redox equation: SO2 + NO2 F1F1F1S1F1F1F10 SO3 + NO, choose an appropriate chemical formula from the list that identifies the substance oxidized.

Accepted Answer

A)  SO2 
B)  SO3 
C)  NO 
D)  NO2 
A)  SO2 
B)  SO3 
C)  NO 
D)  NO2

Question 7

Whether a reaction is exothermic or endothermic is determined by

Accepted Answer

A)  the activation energy 
B)  the physical state of the reactants 
C)  how reactant and product potential energies compare 
D)  whether a catalyst is present 
A)  the activation energy 
B)  the physical state of the reactants 
C)  how reactant and product potential energies compare 
D)  whether a catalyst is present

Question 8

Consider the following redox equation: SO2 + NO2 F1F1F1S1F1F1F10 SO3 + NO, choose an appropriate chemical formula from the list that identifies the substance that loses electrons.

Accepted Answer

A)  SO2 
B)  SO3 
C)  NO 
D)  NO2 
A)  SO2 
B)  SO3 
C)  NO 
D)  NO2

Question 9

Catalysts are correctly characterized by each of the following statements except one. The exception is:

Accepted Answer

A)  They can be either solids, liquids or gases. 
B)  They lower the activation energy for a reaction. 
C)  They do not actively participate in a reaction. 
D)  They are not consumed in a reaction. 
A)  They can be either solids, liquids or gases. 
B)  They lower the activation energy for a reaction. 
C)  They do not actively participate in a reaction. 
D)  They are not consumed in a reaction.

Question 10

Increasing the temperature at which a chemical reaction occurs

Accepted Answer

A)  will lower the activation energy 
B)  causes more reactant collisions to take place in a given time 
C)  increases disorder in the system, thus decreasing the reaction rate 
D)  more than one correct response 
E)  no correct response 
A)  will lower the activation energy 
B)  causes more reactant collisions to take place in a given time 
C)  increases disorder in the system, thus decreasing the reaction rate 
D)  more than one correct response 
E)  no correct response

Question 11

In a redox reaction, the oxidizing agent is the substance

Accepted Answer

A)  that is oxidized 
B)  that loses electrons 
C)  that contains an element that undergoes a decrease in oxidation number 
D)  more than one correct response 
E)  no correct response 
A)  that is oxidized 
B)  that loses electrons 
C)  that contains an element that undergoes a decrease in oxidation number 
D)  more than one correct response 
E)  no correct response

Question 12

In the redox reaction 4Fe + 3 O2 + 12HCl F1F1F1S1F1F1F10 4FeCl3 + 6H2O

Accepted Answer

A)  HCl is the reducing agent. 
B)  O2 is the substance oxidized. 
C)  Fe undergoes an oxidation number decrease of three units per atom. 
D)  More than one correct response. 
E)  No correct response. 
A)  HCl is the reducing agent. 
B)  O2 is the substance oxidized. 
C)  Fe undergoes an oxidation number decrease of three units per atom. 
D)  More than one correct response. 
E)  No correct response.

Question 13

For the following general reaction equation, choose the correct form of the equilibrium constant expression from the response list:

Accepted Answer

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

Question 14

In which of the following sequences of sulfur-containing ions are the ions arranged in order of decreasing oxidation number for S?

Accepted Answer

A)  SO32-, SO42-, S2- 
B)  SO42-, S2O32-, S2- 
C)  S2O32-, SO32-, SO42- 
D)  more than one correct response 
E)  no correct response 
A)  SO32-, SO42-, S2- 
B)  SO42-, S2O32-, S2- 
C)  S2O32-, SO32-, SO42- 
D)  more than one correct response 
E)  no correct response

Question 15

Chemical equilibrium is reached in a system when

Accepted Answer

A)  complete conversion of reactants to products has occurred 
B)  reactant and product concentrations are equal 
C)  reactants are being consumed at the same rate they are being produced 
D)  more than one correct response 
E)  no correct response 
A)  complete conversion of reactants to products has occurred 
B)  reactant and product concentrations are equal 
C)  reactants are being consumed at the same rate they are being produced 
D)  more than one correct response 
E)  no correct response

Question 16

Assign the following reaction to one of the reaction classifications given in the response list: K2CO3 F1F1F1S1F1F1F10 K2O + CO2

Accepted Answer

A)  decomposition 
B)  combination 
C)  displacement 
D)  exchange 
A)  decomposition 
B)  combination 
C)  displacement 
D)  exchange

Question 17

Which substance functions as a reducing agent in the following redox reaction? CH4 + 2 O2 F1F1F1S1F1F1F10 CO2 + 2H2O

Accepted Answer

A)  CH4 
B)  O2 
C)  CO2 
D)  H2O 
A)  CH4 
B)  O2 
C)  CO2 
D)  H2O

Question 18

Use the following to answer the questions below:
In each of the following multiple-choice questions, characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices:
-Characterize EACH of the three given statements as being TRUE or FALSE and then indicate the collective true-false status of the statements using the choices: (1) The square brackets associated with a general equilibrium constant expression mean that concentrations must be expressed in terms of molarity.
(2) Pressure changes affect all chemical systems at equilibrium in which gaseous reactants or products are present.
(3) In the compound KMnO4, the oxidation number of Mn is +3.

Accepted Answer

A)  All three statements are true. 
B)  Two of the three statements are true. 
C)  Only one of the statements is true. 
D)  None of the statements is true. 
A)  All three statements are true. 
B)  Two of the three statements are true. 
C)  Only one of the statements is true. 
D)  None of the statements is true.

Question 19

Which of the following statements concerning types of reactions is correct?

Accepted Answer

A)  The reactant in a decomposition reaction must be a compound. 
B)  The reactants in a combination reaction must be elements. 
C)  The reactants in a displacement reaction could be two compounds. 
D)  More than one correct response. 
E)  No correct response. 
A)  The reactant in a decomposition reaction must be a compound. 
B)  The reactants in a combination reaction must be elements. 
C)  The reactants in a displacement reaction could be two compounds. 
D)  More than one correct response. 
E)  No correct response.

Question 20

The proper assignment of oxidation numbers to the elements in the polyatomic ion SO32- would be

Accepted Answer

A)  +6 for S and -6 for O 
B)  +6 for S and -2 for O 
C)  +4 for S and -6 for O 
D)  +4 for S and -2 for O 
A)  +6 for S and -6 for O 
B)  +6 for S and -2 for O 
C)  +4 for S and -6 for O 
D)  +4 for S and -2 for O

Exam 9: Chemical Reactions

According to Le Chatelier's principle, which of the following effects will occur if NH3 is removed from an equilibrium mixture governed by the equation:

Le Chatelier's principle states that:

For the indicated element, select the correct oxidation number from the response list: oxidation number of Cr in Cr2O72-+.

Consider the following equilibrim: Determine the effect on the position of equilibrium when the temperature is decreased.

Assign the following reaction to one of the reaction classifications given in the response list: 4PH3 + Ni(CO)4  4CO + Ni(PH3)4

Consider the following redox equation: SO2 + NO2  SO3 + NO, choose an appropriate chemical formula from the list that identifies the substance oxidized.

Whether a reaction is exothermic or endothermic is determined by

Consider the following redox equation: SO2 + NO2  SO3 + NO, choose an appropriate chemical formula from the list that identifies the substance that loses electrons.

Catalysts are correctly characterized by each of the following statements except one. The exception is:

Increasing the temperature at which a chemical reaction occurs

In a redox reaction, the oxidizing agent is the substance

In the redox reaction 4Fe + 3 O2 + 12HCl  4FeCl3 + 6H2O

For the following general reaction equation, choose the correct form of the equilibrium constant expression from the response list:

In which of the following sequences of sulfur-containing ions are the ions arranged in order of decreasing oxidation number for S?

Chemical equilibrium is reached in a system when

Assign the following reaction to one of the reaction classifications given in the response list: K2CO3  K2O + CO2

Which substance functions as a reducing agent in the following redox reaction? CH4 + 2 O2  CO2 + 2H2O

Which of the following statements concerning types of reactions is correct?

The proper assignment of oxidation numbers to the elements in the polyatomic ion SO32- would be

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Chemical Bonding: the Ionic Bond Model

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According to Le Chatelier's principle, which of the following effects will occur if NH₃ is removed from an equilibrium mixture governed by the equation:

For the indicated element, select the correct oxidation number from the response list: oxidation number of Cr in Cr₂O₇²^-⁺.

Assign the following reaction to one of the reaction classifications given in the response list: 4PH₃ + Ni(CO)₄  4CO + Ni(PH₃)₄

Consider the following redox equation: SO₂ + NO₂  SO₃ + NO, choose an appropriate chemical formula from the list that identifies the substance oxidized.

Consider the following redox equation: SO₂ + NO₂  SO₃ + NO, choose an appropriate chemical formula from the list that identifies the substance that loses electrons.

In the redox reaction 4Fe + 3 O₂ + 12HCl  4FeCl₃ + 6H₂O

Assign the following reaction to one of the reaction classifications given in the response list: K₂CO₃  K₂O + CO₂

Which substance functions as a reducing agent in the following redox reaction? CH₄ + 2 O₂  CO₂ + 2H₂O

The proper assignment of oxidation numbers to the elements in the polyatomic ion SO₃^2- would be