Question 1

How many electrons are transferred in the following reaction?

Accepted Answer

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

Question 2

Which of the following is true for a reaction that is spontaneous as written?

Accepted Answer

A)  ($\Delta$rGS1U1P1$\circ$S1S1P0) cell > 0 
B)  ($\Delta$rGS1U1P1$\circ$S1S1P0) > 0; ES1U1P1$\circ$S1S1P0cell rGS1U1P1$\circ$S1S1P0) cell rGS1U1P1$\circ$S1S1P0) > 0; ES1U1P1$\circ$S1S1P0cell > 0 
E)  ($\Delta$rGS1U1P1$\circ$S1S1P0) > 0; ES1U1P1$\circ$S1S1P0cell = 0 
A)  ($\Delta$rGS1U1P1$\circ$S1S1P0) cell > 0 
B)  ($\Delta$rGS1U1P1$\circ$S1S1P0) > 0; ES1U1P1$\circ$S1S1P0cell rGS1U1P1$\circ$S1S1P0) cell rGS1U1P1$\circ$S1S1P0) > 0; ES1U1P1$\circ$S1S1P0cell > 0 
E)  ($\Delta$rGS1U1P1$\circ$S1S1P0) > 0; ES1U1P1$\circ$S1S1P0cell = 0

Question 3

For the electrochemical cell Zn(s)| Zn2+ || Ag+ | Ag(s),the standard cell potential is 1.56 V.A cell using these reagents was made,and the observed potential was 1.44 V at 25oC.What is a possible explanation for the observed voltage?

Accepted Answer

A)  The volume of the Zn2+ solution was larger than the volume of the Ag+ solution. 
B)  The volume of the Ag+ solution was larger than the volume of the Zn2+ solution. 
C)  The Zn2+ concentration was larger than the Ag+ concentration. 
D)  The Ag electrode was twice as large as the Zn electrode. 
E)  The Ag+ concentration was larger than the Zn2+ concentration. 
A)  The volume of the Zn2+ solution was larger than the volume of the Ag+ solution. 
B)  The volume of the Ag+ solution was larger than the volume of the Zn2+ solution. 
C)  The Zn2+ concentration was larger than the Ag+ concentration. 
D)  The Ag electrode was twice as large as the Zn electrode. 
E)  The Ag+ concentration was larger than the Zn2+ concentration.

Question 4

What is the value of the reaction quotient,Q,for the voltaic cell constructed from the following two half-reactions when the Zn2+ concentration is 0.0120 M and the Ag+ concentration is 1.25 M?

Accepted Answer

A)  9.60 $\times$ 10-3 
B)  7.68 $\times$ 10-3 
C)  104 
D)  1.25 $\times$ 10-2 
E)  130 
A)  9.60 $\times$ 10-3 
B)  7.68 $\times$ 10-3 
C)  104 
D)  1.25 $\times$ 10-2 
E)  130

Question 5

What is the copper(II)-ion concentration at 25°C in the cell Zn(s)| Zn2+(aq,1.0 M)|| Cu2+(aq)| Cu(s)if the measured cell potential is 1.01 V? The standard cell potential is 1.10 V.

Accepted Answer

A)  0.030 M 
B)  0.99 M 
C)  0.00091 M 
D)  1.0 M 
E)  0.99M 
A)  0.030 M 
B)  0.99 M 
C)  0.00091 M 
D)  1.0 M 
E)  0.99M

Question 6

Which of the following species are likely to behave as oxidizing agents: Li(s),H2(g),MnO4-(aq),and Cl-(aq)?

Accepted Answer

A)  Li(s)only 
B)  MnO4-(aq)only 
C)  H2(g)and Cl-(aq) 
D)  Li(s)and MnO4-(aq) 
E)  Cl-(aq)only 
A)  Li(s)only 
B)  MnO4-(aq)only 
C)  H2(g)and Cl-(aq) 
D)  Li(s)and MnO4-(aq) 
E)  Cl-(aq)only

Question 7

What half-reaction occurs at the cathode during the electrolysis of molten potassium bromide?

Accepted Answer

A)  K(s) $\to$K+( $\ell$ )+ e- 
B)  Br2( $\ell$ )+ 2e- $\to$ 2Br-( $\ell$ ) 
C)  2Br-( $\ell$ ) $\to$ Br2( $\ell$ )+ 2e- 
D)  K+( $\ell$ )+ e- $\to$ K(s) 
E)  2H2O( $\ell$ )+ 2e- $\to$ H2(g)+ 2OH-(( $\ell$ ) 
A)  K(s) $\to$K+( $\ell$ )+ e- 
B)  Br2( $\ell$ )+ 2e- $\to$ 2Br-( $\ell$ ) 
C)  2Br-( $\ell$ ) $\to$ Br2( $\ell$ )+ 2e- 
D)  K+( $\ell$ )+ e- $\to$ K(s) 
E)  2H2O( $\ell$ )+ 2e- $\to$ H2(g)+ 2OH-(( $\ell$ )

Question 8

Calculate Ecell for the following electrochemical cell at 25 S1U1P1$\circ$S1S1P0C
Pt(s)| H2(g,1.00 atm)| H+(aq,1.00 M)|| Sn2+(aq,0.350 M),Sn4+(aq,0.020 M)| Pt(s)
Given the following standard reduction potentials.
Sn4+(aq)+ 2 e- $\to$Sn2+(s)$~~~~~~~~$ES1U1P1$\circ$S1S1P0 = +0.15 V
2 H+(aq)+ 2 e- $\to$ H2(g)$~~~~~~~~$ES1U1P1$\circ$S1S1P0 = 0.00 V

Accepted Answer

A)  -0.19 V 
B)  +0.08 V 
C)  +0.11 V 
D)  +0.19 V 
E)  +0.22 V 
A)  -0.19 V 
B)  +0.08 V 
C)  +0.11 V 
D)  +0.19 V 
E)  +0.22 V

Question 9

When the following oxidation-reduction reaction in acidic solution is balanced,what is the lowest whole-number coefficient for H+,and on which side of the balanced equation should it appear?
MnO4-(aq)+ I-(aq) $\to$Mn2+(aq)+ I2(s)

Accepted Answer

A)  1,reactant side 
B)  2,product side 
C)  8,reactant side 
D)  16,reactant side 
E)  4,product side 
A)  1,reactant side 
B)  2,product side 
C)  8,reactant side 
D)  16,reactant side 
E)  4,product side

Question 10

According to the following cell notation,which species is undergoing reduction?
Cu | Cu2+(aq)|| Mn2+(aq)| MnO2(s)| Pt(s)

Accepted Answer

A)  Mn2+(aq) 
B)  Cu2+(aq) 
C)  Cu(s) 
D)  MnO2(s) 
E)  Pt(s) 
A)  Mn2+(aq) 
B)  Cu2+(aq) 
C)  Cu(s) 
D)  MnO2(s) 
E)  Pt(s)

Question 11

Calculate   for the electrochemical cell below,
Pb(s)|PbCl2(s)| Cl-(aq,1.0 M)|| Fe3+(aq,1.0 M),Fe2+(aq,1.0 M)| Pt(s)
Given the following reduction half-reactions.

Pb2+(aq)+ 2 e- $\to$ Pb(s)$~~~ ~~~~$$~~~ ~~~~$$~~~~~~~~$ES1U1P1$\circ$S1S1P0 = -0.126 V
PbCl2(s)+ 2 e- $\to$ Pb(s)+ 2 Cl-(aq)$~~~~~~~~$ES1U1P1$\circ$S1S1P0 = -0.267 V
Fe3+(aq)+ e- $\to$ Fe2+(aq)$~~~~ ~$$~~~~~~~~$$~~~~~~~~$ES1U1P1$\circ$S1S1P0 = +0.771 V
Fe2+(aq)+ e- $\to$ Fe(s)$~~~~~~~~$$~~ ~~~~~$$~ ~ ~$$~~~~~~~~$ES1U1P1$\circ$S1S1P0 = -0.44 V

Accepted Answer

A)  -0.504 V 
B)  -0.062 V 
C)  +0.504 V 
D)  +1.038 V 
E)  +1.604 V 
A)  -0.504 V 
B)  -0.062 V 
C)  +0.504 V 
D)  +1.038 V 
E)  +1.604 V

Question 12

What is a correct cell notation for a voltaic cell based on the reaction below?
Cu2+(aq)+ Pb(s)+ SO42-(aq)$\to$ Cu(s)+ PbSO4(s)

Accepted Answer

A)  Pb(s)| PbSO4(s)|| Cu2+(aq)|| Cu(s) 
B)  Cu(s)| Cu2+(aq)|| SO42-(aq)| PbSO4(s)| Pb(s) 
C)  Cu(s)| Cu2+(aq),SO42-(aq)| PbSO4(s)| Pb(s) 
D)  Cu(s)| Cu2+(aq),SO42-(aq)|| PbSO4(s)|| Pb(s) 
E)  Pb(s)| PbSO4(s)| SO42-(aq)|| Cu2+(aq)|| Cu(s) 
A)  Pb(s)| PbSO4(s)|| Cu2+(aq)|| Cu(s) 
B)  Cu(s)| Cu2+(aq)|| SO42-(aq)| PbSO4(s)| Pb(s) 
C)  Cu(s)| Cu2+(aq),SO42-(aq)| PbSO4(s)| Pb(s) 
D)  Cu(s)| Cu2+(aq),SO42-(aq)|| PbSO4(s)|| Pb(s) 
E)  Pb(s)| PbSO4(s)| SO42-(aq)|| Cu2+(aq)|| Cu(s)

Question 13

If electric current is passed through a solution of molten KBr,the product at the cathode is ________.

Accepted Answer

The answer of If electric current is passed through a...

Question 14

What is the balanced spontaneous reaction and standard cell potential of an electrochemical cell constructed from half cells with the following half reactions?
Fe2+(aq)+ 2e-$\to$ Fe(s) $~~~~~~~~$$~~~~~~~~$E° = -0.440 V
Pb2+(aq)+ 2e-$\to$ Pb(s) $~~~~~~~~$$~~~~~~~~$E° = -0.130 V

Accepted Answer

A)  Pb2+(aq)+ Fe(s)$\to$Pb(s)+ Fe2+(aq)   =0.310 V 
B)  Pb(s)+ Fe2+(aq)$\to$ Pb2+(aq)+ Fe(s)   =-0.310 V 
C)  Pb2+(aq)+ Fe2+(aq)$\to$ Pb(s)+ Fe(s)   =-0.570 V 
D)  Pb2+(aq)+ Fe(s)$\to$Pb(s)+ Fe2+(aq)   =0.155 V 
E)  Pb(s)+ Fe2+(aq)$\to$ Pb2+(aq)+ Fe(s)   =-0.155 V 
A)  Pb2+(aq)+ Fe(s)$\to$Pb(s)+ Fe2+(aq)   =0.310 V 
B)  Pb(s)+ Fe2+(aq)$\to$ Pb2+(aq)+ Fe(s)   =-0.310 V 
C)  Pb2+(aq)+ Fe2+(aq)$\to$ Pb(s)+ Fe(s)   =-0.570 V 
D)  Pb2+(aq)+ Fe(s)$\to$Pb(s)+ Fe2+(aq)   =0.155 V 
E)  Pb(s)+ Fe2+(aq)$\to$ Pb2+(aq)+ Fe(s)   =-0.155 V

Question 15

Which of the following statements is true concerning half-cell II as the voltaic cell shown below discharges?

Accepted Answer

A)  [Cu2+] decreases with time,and [K+] increases with time. 
B)  [Cu2+] increases with time,and [K+] increases with time. 
C)  [Cu2+] decreases with time,and [K+] decreases with time. 
D)  [Cu2+] decreases with time,and [SO4-] decreases with time. 
E)  [Cu2+] increases with time,and [SO4-] increases with time. 
A)  [Cu2+] decreases with time,and [K+] increases with time. 
B)  [Cu2+] increases with time,and [K+] increases with time. 
C)  [Cu2+] decreases with time,and [K+] decreases with time. 
D)  [Cu2+] decreases with time,and [SO4-] decreases with time. 
E)  [Cu2+] increases with time,and [SO4-] increases with time.

Question 16

The cell potential of the following electrochemical cell is determined using an unspecified concentration of acid.What is the pH of the acid solution given that the measured cell potential is -0.558 V and the anode reduction potential (ES1U1P1$\circ$S1S1P0is 0.222 V at 25S1U1P1$\circ$S1S1P0C?
Ag(s)| AgCl(s)| Cl-(aq,1.0 M)|| H+(aq,? M)| H2(g,1.0 atm)| Pt(s)

Accepted Answer

A)  5.68 
B)  13.2 
C)  6.18 
D)  11.4 
E)  1.32 
A)  5.68 
B)  13.2 
C)  6.18 
D)  11.4 
E)  1.32

Question 17

Calculate Ecell for the following electrochemical cell at 25 S1U1P1$\circ$S1S1P0C
Pt(s)| Fe3+(aq,0.100 M),Fe2+(aq,0.040 M)|| Cl-(aq,0.50 M)| AgCl(s)| Ag(s)
Given the following standard reduction potentials.
AgCl(s)+ e- $\to$ Ag(s)+ Cl-(aq)$~~~~~~~~$ES1U1P1$\circ$S1S1P0 = +0.222 V
Fe3+(aq)+ e- $\to$ Fe2+(aq)$~~~~~~~~$$~~~~~~~~$ES1U1P1$\circ$S1S1P0 = +0.771 V

Accepted Answer

A)  -1.034 V 
B)  -0.590 V 
C)  -0.508 V 
D)  -0.555 V 
E)  +1.034 V 
A)  -1.034 V 
B)  -0.590 V 
C)  -0.508 V 
D)  -0.555 V 
E)  +1.034 V

Question 18

What is the pH of the solution at the cathode if   = -0.362 V for the following electrochemical cell at 25 S1U1P1$\circ$S1S1P0C?
Pt | H2(g,1.0 atm)| H+(aq,1.00 M)|| H+(aq)| H2(g,1.0 atm)| Pt

Accepted Answer

A)  1.77 
B)  3.06 
C)  6.11 
D)  7.89 
E)  12.23 
A)  1.77 
B)  3.06 
C)  6.11 
D)  7.89 
E)  12.23

Question 19

What charge,in coulombs,is required to deposit 1.5 g Mg(s)from a solution of Mg2+(aq)?

Accepted Answer

A)  4.1 $\times$ 102 C 
B)  6.0 $\times$ 103 C 
C)  1.2 $\times$ 104 C 
D)  2.9 $\times$ 105 C 
E)  3.1 $\times$ 106 C 
A)  4.1 $\times$ 102 C 
B)  6.0 $\times$ 103 C 
C)  1.2 $\times$ 104 C 
D)  2.9 $\times$ 105 C 
E)  3.1 $\times$ 106 C

Question 20

If the value of E°cell is   for the reaction  
What is the value of E°cell for  
½ Cl2(g)?

Accepted Answer

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

Exam 20: Principles of Reactivity: Electron Transfer Reactions

How many electrons are transferred in the following reaction?

Which of the following is true for a reaction that is spontaneous as written?

For the electrochemical cell Zn(s)| Zn2+ || Ag+ | Ag(s),the standard cell potential is 1.56 V.A cell using these reagents was made,and the observed potential was 1.44 V at 25oC.What is a possible explanation for the observed voltage?

What is the value of the reaction quotient,Q,for the voltaic cell constructed from the following two half-reactions when the Zn2+ concentration is 0.0120 M and the Ag+ concentration is 1.25 M?

What is the copper(II)-ion concentration at 25°C in the cell Zn(s)| Zn2+(aq,1.0 M)|| Cu2+(aq)| Cu(s)if the measured cell potential is 1.01 V? The standard cell potential is 1.10 V.

Which of the following species are likely to behave as oxidizing agents: Li(s),H2(g),MnO4-(aq),and Cl-(aq)?

What half-reaction occurs at the cathode during the electrolysis of molten potassium bromide?

When the following oxidation-reduction reaction in acidic solution is balanced,what is the lowest whole-number coefficient for H+,and on which side of the balanced equation should it appear? MnO4-(aq)+ I-(aq) →\to→ Mn2+(aq)+ I2(s)

According to the following cell notation,which species is undergoing reduction? Cu | Cu2+(aq)|| Mn2+(aq)| MnO2(s)| Pt(s)

What is a correct cell notation for a voltaic cell based on the reaction below? Cu2+(aq)+ Pb(s)+ SO42-(aq) →\to→ Cu(s)+ PbSO4(s)

If electric current is passed through a solution of molten KBr,the product at the cathode is ________.

What is the balanced spontaneous reaction and standard cell potential of an electrochemical cell constructed from half cells with the following half reactions? Fe2+(aq)+ 2e- →\to→ Fe(s) ~~~~~~~~ ~~~~~~~~ E° = -0.440 V Pb2+(aq)+ 2e- →\to→ Pb(s) ~~~~~~~~ ~~~~~~~~ E° = -0.130 V

Which of the following statements is true concerning half-cell II as the voltaic cell shown below discharges?

What is the pH of the solution at the cathode if = -0.362 V for the following electrochemical cell at 25 ∘\circ∘ C? Pt | H2(g,1.0 atm)| H+(aq,1.00 M)|| H+(aq)| H2(g,1.0 atm)| Pt

What charge,in coulombs,is required to deposit 1.5 g Mg(s)from a solution of Mg2+(aq)?

If the value of E°cell is for the reaction What is the value of E°cell for ½ Cl2(g)?

Basic Concepts of Chemistry

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Stoichiometry: Quantitative Information About Chemical Reactions

Principles of Chemical Reactivity: Energy and Chemical Reactions

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Bonding and Molecular Structure: Orbital Hybridization and Molecular Orbitals

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Intermolecular Forces and Liquids

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Solutions and Their Behavior

Chemical Kinetics: the Rates of Chemical Reactions

Principles of Reactivity: Chemical Equilibria

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For the electrochemical cell Zn(s)| Zn²⁺ || Ag⁺ | Ag(s),the standard cell potential is 1.56 V.A cell using these reagents was made,and the observed potential was 1.44 V at 25^oC.What is a possible explanation for the observed voltage?

What is the value of the reaction quotient,Q,for the voltaic cell constructed from the following two half-reactions when the Zn²⁺ concentration is 0.0120 M and the Ag⁺ concentration is 1.25 M?

What is the copper(II)-ion concentration at 25°C in the cell Zn(s)| Zn²⁺(aq,1.0 M)|| Cu²⁺(aq)| Cu(s)if the measured cell potential is 1.01 V? The standard cell potential is 1.10 V.

Which of the following species are likely to behave as oxidizing agents: Li(s),H₂(g),MnO₄^-(aq),and Cl^-(aq)?

When the following oxidation-reduction reaction in acidic solution is balanced,what is the lowest whole-number coefficient for H⁺,and on which side of the balanced equation should it appear? MnO₄^-(aq)+ I^-(aq) $\to$ Mn²⁺(aq)+ I₂(s)

According to the following cell notation,which species is undergoing reduction? Cu | Cu²⁺(aq)|| Mn²⁺(aq)| MnO₂(s)| Pt(s)

What is a correct cell notation for a voltaic cell based on the reaction below? Cu²⁺(aq)+ Pb(s)+ SO₄^2-(aq) $\to$ Cu(s)+ PbSO₄(s)

What is the balanced spontaneous reaction and standard cell potential of an electrochemical cell constructed from half cells with the following half reactions? Fe²⁺(aq)+ 2e^- $\to$ Fe(s) $$ $$ E° = -0.440 V Pb²⁺(aq)+ 2e^- $\to$ Pb(s) $$ $$ E° = -0.130 V

What charge,in coulombs,is required to deposit 1.5 g Mg(s)from a solution of Mg²⁺(aq)?

If the value of E°_cell is for the reaction What is the value of E°_cell for ½ Cl₂(g)?