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Chemistry
Q:
The electrolysis of an aqueous solution of NS produces oxygen at the anode according to the following equation:Calculate the volume of at STP that is produced by the passage of 3.00 A through this solution for 150 minutes.A) 1.57 LB) 0.0261 LC) 6.28 LD) 0.0700 L
Q:
When an aqueous solution of NaCl is electrolyzed is produced at the cathode according to the following equation:If 3.13 L of at STP was produced and the current passing through the cell was 0.250 A, how long did it take to produce the ?A) 30.0 hoursB) 14.2 hoursC) 29.7 minutesD) 40.1 minutes
Q:
The gas OF2 can be produced from the electrolysis of an aqueous solution of KF, as shown in the equation below.OF2(g) + 2 H+(aq) + 4 e- -> H2O(l) + 2 F-(aq) E = +2.15 VUsing the given standard reduction potential, calculate the amount of OF2 that is produced, and the electrode at which the OF2 is produced, upon the passage of 0.240 faradays through an aqueous KF solution.A) 3.24 g of OF2 at the anodeB) 13.0 g of OF2 at the anodeC) 3.24 g of OF2 at the cathodeD) 13.0 g of OF2 at the cathode
Q:
Which of the following statements concerning the electrorefining of copper in not true?
A) The anode is constructed of chalcocite, Cu2S.
B) The anode mud is a valuable source of silver, gold, and platinum.
C) Copper is oxidized at the anode and copper(II) ions are reduced at the cathode.
D) The process is used to purify copper.
Q:
Which requires the most electricity (in terms of faradays of charge transferred) per gram of useful product formed?
A) electrolysis of aqueous NaCl (chlor-alkali industry)
B) electrolysis of molten NaCl/CaCl2 in a Downs cell
C) electrorefining copper metal
D) production of aluminum in the Hall-Heroult process
Q:
The Hall-Heroult process for the production of aluminum involves the electrolysis of
A) an aqueous solution of Al(NO3)3.
B) molten Al2O3.
C) molten cryolite, Na3AlF6.
D) a molten mixture of Al2O3 and Na3AlF6.
Q:
The chlor-alkali industry is based on the electrolysis of aqueous NaCl. What are the products of this electrolysis?
A) Na and Cl2
B) NaOH, H2, and O2
C) NaOH, H2, and Cl2
D) NaOH, O2, and Cl2
Q:
O2(g) + 4 H+(aq) + 4 e- -> 2 H2O(l) E = +1.23 VPb2+(aq) + 2 e- -> Pb(s) E = -0.13 V2 H2O(l) + 2 e- -> H2(g) + 2 OH-(aq) E = -0.83 VBased on the half-reactions above, electrolysis of an aqueous solution of Pb(NO3)2 is expected to produce.A) Pb at the cathode and H2 at the anode.B) Pb at the cathode and O2 at the anode.C) H2 at the cathode and Pb at the anode.D) O2 at the cathode and Pb at the anode.
Q:
O2(g) + 4 H+(aq) + 4 e--> 2 H2O(l) E = +1.23 VI2(s) + 2 e- -> 2 I-(aq) E = +0.54 V2 H2O(l) + 2 e- -> H2(g) + 2 OH-(aq) E = -0.83 VMg2+(aq) + 2 e- -> Mg(s) E = -2.37 VBased on the data above, electrolysis of an aqueous solution of MgI2, with inert electrodes, is expected to produceA) Mg at the cathode and I2 at the anode.B) H2 at the cathode and I2 at the anode.C) Mg at the cathode and O2 at the anode.D) H2 at the cathode and O2 at the anode.
Q:
Which statement concerning overvoltage is false?
A) Overvoltage is the additional voltage above the calculated voltage required to bring about electrolysis.
B) Overvoltage is often due to a high activation energy for the reaction at one electrode.
C) Overvoltage is small for half-reactions involving the formation of O2(g) or H2(g).
D) Overvoltage must be experimentally determined.
Q:
Which statement is true?
A) The cathode is positive for a galvanic cell and negative for an electrolytic cell.
B) Electrons flow through the external circuit to the cathode in a galvanic cell and to the anode in an electrolytic cell.
C) Oxidation occurs at the anode in a galvanic cell and at the cathode in an electrolytic cell.
D) Oxidation occurs at the cathode in a galvanic cell and at the anode in an electrolytic cell.
Q:
For a dead batteryA) E is negative and G is positive for the cell reaction.B) E is negative and G is negative for the cell reaction.C) E is zero and G is positive for the cell reaction.D) E is zero and G is zero for the cell reaction.
Q:
For an electrolytic cellA) E is negative and G is negative for the cell reaction.B) E is negative and G is positive for the cell reaction.C) E is positive and G is negative for the cell reaction.D) E is positive and G is positive for the cell reaction.
Q:
An electrolytic cell is
A) a battery.
B) a cell in which the cell reaction is spontaneous.
C) a cell in which an electric current drives a nonspontaneous reaction.
D) a cell in which reactants are continuously supplied to the cell.
Q:
A steel pipe can be protected from corrosion by attaching the pipe to a piece of magnesium because
A) magnesium forms a tight oxide coating.
B) magnesium is more easily oxidized than iron.
C) magnesium is inert.
D) magnesium and steel form a corrosion resistant alloy.
Q:
Aluminum requires relatively little protection from corrosion because
A) aluminum has little tendency to react with oxygen.
B) the reduction potential for Al3+/Al is very low.
C) the oxidation of aluminum produces a hard, relatively impenetrable film of Al2O3.
D) aluminum is protected by cathodic protection.
Q:
What is least easily oxidized?
A) Al
B) Fe
C) Mg
D) Zn
Q:
Galvanized steel is steel coated with a layer of
A) Fe2O3.
B) Mg.
C) Sn.
D) Zn.
Q:
Which of the following statements concerning the rusting of iron is false?
A) The oxidation site can occur at a different place on the metal surface than the reduction site.
B) The metal is reduced.
C) The rusting of iron requires both oxygen and water.
D) Salt increases the rate of corrosion by providing ions to carry the current.
Q:
Shown below are the reactions occurring in the proton-exchange membrane (PEM) fuel cell.I 2 H2(g) -> 4 H+(aq) + 4 e-II O2(g) + 4 H+(aq) + 4 e- -> 2 H2O(l)Overall 2 H2(g) + O2(g) -> 2 H2O(l)Which is the cathode reaction, and what is being oxidized in the overall reaction?A) I, H2B) I, O2C) II, H2D) II, O2
Q:
Shown below are the reactions occurring in the direct methanol fuel cell (DMFC).I 2 CH3OH(aq) + 2 H2O(l) -> 2 CO2(g) +12 H+(aq) +12 e-II 3 O2(g) + 12 H+(aq) + 12 e- -> 6 H2O(l)Overall 2 CH3OH(aq) + 3 O2(g) -> 2 CO2(g) + 4 H2O(l)Which is the anode reaction, and what is being oxidized in the overall reaction?A) I, CH3OHB) I, H2OC) II, O2D) II, H+
Q:
Which of the following statements concerning a lithium battery is false?
A) A lithium battery is rechargeable.
B) A lithium battery has a relatively high voltage, due in part to the high oxidation potential of lithium.
C) It takes a small mass of lithium to provide one mole of electrons in the cell reaction.
D) The cell reaction produces toxic mercury, so the batteries should be recycled.
Q:
Which of the following reactions is most suitable for a fuel cell?A) MnO2(s) + Li(s) -> LiMnO2(s)B) Pb(s) + PbO2(s) + 2 H+(aq) + HSO4-(aq) -> PbSO4(s) + 2 H2O(l)C) HgO(l) + Zn(s) -> ZnO(s) + Hg(l)D) 2 CO(g) + O2(g) -> 2 CO2(g)
Q:
Which statement below is not true?
A) The cell reactants in a fuel cell are continuously supplied from an external source.
B) A fuel cell is a galvanic cell.
C) Modern fuel cells can be easily regenerated using household current.
D) One of the reactants in a fuel cell is a traditional fuel.
Q:
Which battery does not use MnO2(s) as a cell reactant?
A) an alkaline dry cell
B) a Leclanche' dry cell
C) a lithium battery
D) a "ni-cad" battery
Q:
The cell reaction for a lead storage battery is:Pb(s) + PbO2(s) + 2 H+(aq) + 2 HSO4-(aq) -> 2 PbSO4(s) + 2 H2O(l)E = +1.92 VTo provide a potential of about 12 V, one couldA) adjust the pH to 12.B) adjust the pH to 1.C) connect six cells in series.D) greatly increase the surface area of the Pb(s) and PbO2(s).
Q:
For a particular battery based on one of the following reactions, E is expected to remain constant with time until the cell reactants are almost completely consumed. Which is the appropriate reaction?A) Zn(s) + 2 MnO2(s) + 2 NH4+(aq) -> 2 NH3(aq) + Mn2O3(s) + Zn2+(aq) + H2O(l)B) 2 NiO(OH)(s) + Cd(s) + 2 H2O(l) -> 2 Ni(OH)2(s) + Cd(OH)2(s)C) Pb(s) + PbO2(s) + 2 H+(aq) + 2 HSO4-(aq) -> 2 PbSO4(s) + 2 H2O(l)D) Zn(s) + Cu2+(aq) -> Zn2+(aq) + Cu(s)
Q:
A particular 12V battery is based on a reaction having a standard cell potential, E = +1.92 V. What happens when the battery "dies" ?
A) E = 0 V and E = 0 V
B) E = 0 V and E = 12 V
C) E = +1.92 V and E = 0 V
D) E = +1.92 V and E = 12 V
Q:
For a particular cell based on the reaction:3 AgCl(s) + Al(s) -> 3 Ag(s) + Al3+(aq) + 3 Cl-(aq)E = +1.750 V and E = +1.884 V at 25C. What is the value of the equilibrium constant, K, at 25C for the reaction?A) 3.6 1029B) 6.7 1031C) 4.8 1088D) 3.0 1095
Q:
Ag+(aq) + e- -> Ag(s) E = +0.800 VAgBr(s) + e- -> Ag(s) + Br-(aq) E = +0.071 VBr2(l) + 2 e- -> 2 Br-(aq) E = +1.066 VUse some of the data above to calculate Ksp at 25C for AgBr.A) 6.3 10-2B) 4.9 10-13C) 1.9 10-15D) 2.4 10-34
Q:
Calculate the equilibrium constant, K, at 25C for the galvanic cell reaction shown below:8 H+(aq) + 5 Fe2+(aq) + MnO4-(aq) -> Mn2+(aq) + 5 Fe3+(aq) + 4 H2O(l) E = +0.74 VA) 3.2 10-63B) 3.2 10-13C) 3.2 1012D) 3.2 1062
Q:
Q:
The equilibrium constant, K, can be calculated from
A) E.
B) E.
C) either E or E.
D) neither E nor E.
Q:
When a cell reaction reaches equilibrium,
A) E = 0.
B) E = 0.
C) both E and E = 0.
D) neither E nor E = 0.
Q:
Consider the following cell:Where pHA is the pH of the aqueous solution in the anode half-cell and pHC is the pH of the aqueous solution in the cathode half-cell. If the partial pressure of H2(g) is the same for both half-cells, (p1 = p2), then E for the cell at 25°C isA) 0.0296 V log (pHA/pHC).B) 0.0296 V log (pHC/pHA).C) 0.0592 V (pHA - pHC).D) 0.0592 V (pHC - pHA).
Q:
Consider a cell based on the following reaction:GeO(s) + H2O(l) + 2 Ag+(aq) -> GeO2(s) + 2 H+(aq) + 2 Ag(s)If [Ag+] = 1 M, at 25C,A) pH = 2(E - E)/0.0592 V.B) pH = (E - E)/0.0592 V.C) pH = (E - E)/0.0592 V.D) pH = 2(E - E)/0.0592 V.
Q:
A cell based on the reaction below has a standard potential of +0.42 V at 25C. If all of the species are at standard conditions except [H+], at what pH will the cell have a potential of zero?H2O2(aq) + 2 H+(aq) + 2 Cl-(aq) -> Cl2(aq) + 2 H2O(l)A) 3.55B) 7.09C) 10.6D) 14.2
Q:
The following cell has a potential of 0.45 V at 25C.The standard half-cell potential for the half-reaction Hg2Cl2(s) + 2 e- -> 2 Hg(l) + 2 Cl-(aq) is 0.28 V. What is the pH in the anode compartment?A) 2.9B) 4.7C) 7.6D) 12.3
Q:
Which is most often used in the laboratory to measure pH?
A) a standard hydrogen electrode
B) a glass electrode
C) a Daniell cell
D) a conductivity cell
Q:
Consider the half-reaction: The formation of MnO4- from Mn2+ occurs most readily when the solution is
A) acidic.
B) neutral.
C) basic.
D) The reaction is not dependent upon pH.
Q:
How many moles of electrons, n, are transferred in the following reduction-oxidation reaction?2 MnO4-(aq) + 16 H+(aq) + 10 Cl-(aq) -> 2 Mn2+(aq) + 5 Cl2(g) + 8 H2O(l)?A) 2B) 4C) 5D) 10
Q:
If the cell reaction involves ions in solution, as the cell reaction in a galvanic cell continues,
A) E for the cell increases.
B) E for the cell decreases.
C) E for the cell increases.
D) E for the cell decreases.
Q:
A) -0.09 VB) +0.12 VC) +0.15 VD) +0.30 V
Q:
Q:
A) +0.779 VB) +0.935 VC) +1.015 VD) +1.134 V
Q:
At 25C, E = +1.88 V for a cell based on the reaction3 AgCl(s) + Al(s) -> 3 Ag(s) + Al3+(aq) + 3 Cl-(aq).Find the cell potential E if [Al3+] = 0.20 M and [Cl-] = 0.010 M.A) +2.01 VB) +2.04 VC) +2.28 VD) cannot be calculated without the amounts of AgCl, Al, and Ag
Q:
Calculate the cell potential E at 25C for the reactiongiven that [Fe2+] = 0.020 M, [Al3+] = 0.10 M, and the standard reduction potential is -1.66 V for Al3+/Al and -0.45 V for Fe2+/Fe.A) +1.03 VB) +1.17 VC) +1.18 VD) +1.20 V
Q:
Calculate the cell potential at 25C for the cellgiven that the standard reduction potential for Fe2+/Fe is -0.45 V and for Pd2+/Pd is +0.95 V.A) +1.16 VB) +1.28 VC) +1.52 VD) +1.68 V
Q:
Calculate the value of the reaction quotient, Q, for the galvanic cell expressed using shorthand notation below.Use the balanced chemical equation that has the smallest, whole number stoichiometric coefficients.A) 156B) 125C) 8.00 10-3D) 6.40 10-3
Q:
Consider the galvanic cell, Which one of the following changes to the cell would cause the cell potential to increase (i.e., become more positive)?
A) decrease the mass of Pt
B) increase the mass of Pt
C) decrease the pH
D) increase the pH
Q:
Consider the galvanic cell, Which one of the following changes to the cell would cause the cell potential to increase (i.e., become more positive)?
A) increase the [Pb2+] concentration
B) increase the [Cu2+] concentration
C) increase the mass of Pb(s)
D) decrease the mass of Pb(s)
Q:
Consider the following table of standard half-cell potentials:A2 + 2 e- -> 2 A- E = + 1.09 VB4+ + 2 e- -> B2+ E = + 0.15 VC3+ + 3 e- -> C E = - 1.66 VD2+ + 2 e- -> D E = - 2.37 VWhich substance is the strongest oxidizing agent?A) A2B) B4+C) C3+D) D2+
Q:
Use Table 17.1 to determine which of the following is the best oxidizing agent.
A) Fe3+
B) I2
C) MnO4-
D) Pb2+
Q:
Use Table 17.1 to calculate the standard potential for the reactionO2(g) + 4 H+(aq) + 2 Cu(s) -> 2 Cu2+(aq) + 2 H2O(l).A) -1.57 VB) -0.89 VC) +0.89 VD) +1.57 V
Q:
Using Table 17.1, find E for 2 H2O(l) -> 2 H2(g) + O2(g).A) -2.06 VB) -1.23 VC) -0.80 VD) -0.40 V
Q:
According to Table 17.1, which will reduce water but not Mg2+?
A) Al3+(aq)
B) Al(s)
C) Na+(aq)
D) Na(s)
Q:
According to Table 17.1, which aqueous metal ion will reduce Ag+, but not Cu2+?A) Fe2+B) Fe3+C) Mn2+D) Sn2+
Q:
Given: Ag+(aq) + e- -> Ag(s) E = +0.799 VAgI(s) + e- -> Ag(s) + I-(aq) E = -0.152 VNi2+(aq) + 2 e- -> Ni(s) E = -0.267 VWhich of the following reactions should be spontaneous under standard conditions?I. 2 AgI(s) + Ni(s) -> 2 Ag(s) + 2 I-(aq) + Ni2+(aq)II. Ag+(aq) + I-(aq) -> AgI(s)A) I and II are both nonspontaneous.B) I is nonspontaneous and II is spontaneous.C) I is spontaneous and II is nonspontaneous.D) I and II are both spontaneous.
Q:
Using the following standard reduction potentialsFe3+(aq) + e- -> Fe2+(aq) E = +0.77 VPb2+(aq) + 2 e- -> Pb(s) E = -0.13 Vcalculate the standard cell potential for the galvanic cell reaction given below, and determine whether or not this reaction is spontaneous under standard conditions.Pb2+(aq) + 2 Fe2+(aq) -> 2 Fe3+(aq) + Pb(s)A) E = -0.90 V, nonspontaneousB) E = -0.90 V, spontaneousC) E = +0.90 V, nonspontaneousD) E = +0.90 V, spontaneous
Q:
Based on the following information,F2(g) + 2 e- -> 2 F-(aq) E = +2.87 VMg2+(aq) + 2 e- -> 2 Mg(s) E = -2.37 Vwhich of the following chemical species is the strongest reducing agent?A) F2(g)B) Mg2+(aq)C) F-(aq)D) Mg(s)
Q:
Consider the following standard reduction potentials,Al3+(aq) + 3 e- -> Al(s) E = -1.66 VI2(s) + 2 e- -> 2 I-(aq) E = +0.54 VUnder standard conditions,A) Al3+(aq) is a stronger oxidizing agent than I2(s), and I-(aq) is a stronger reducing agent than Al(s).B) I2(s) is a stronger oxidizing agent than Al3+(aq), and Al(s) is a stronger reducing agent than I-(aq).C) Al(s) is a stronger oxidizing agent than I-(aq), and Al3+(aq) is a stronger reducing agent than I2(s).D) I-(aq) is a stronger oxidizing agent than Al(s), and I2(s) is a stronger reducing agent than Al3+(aq).
Q:
A galvanic cell consists of one half-cell that contains Ag(s) and Ag+(aq), and one half-cell that contains Cu(s) and Cu2+(aq). What species are produced at the electrodes under standard conditions?Ag+(aq) + e- -> Ag(s) E = +0.80 VCu2+(aq) + 2 e- -> Cu(s) E = +0.34 VA) Ag(s) is formed at the cathode, and Cu(s) is formed at the anode.B) Ag(s) is formed at the cathode, and Cu2+ (aq) is formed at the anode.C) Cu(s) is formed at the cathode, and Ag+(aq) is formed at the anode.D) Cu2+(aq) is formed at the cathode, and Cu(s) is formed at the anode.
Q:
A galvanic cell consists of a La3+/La half-cell and a standard hydrogen electrode. If the La3+/La half-cell standard cell functions as the anode, and the standard cell potential is 2.52 V, what is the standard reduction potential for the La3+/La half-cell?
A) -2.52 V
B) -0.84 V
C) +0.84 V
D) +2.52 V
Q:
The standard potential for the following galvanic cell is +0.90 V:3 Cu2+(aq) + 2 Ga(s) 3 Cu(s) + 2 Ga3+(aq)Given that the standard reduction potential for the Cu2+/Cu half-cell is +0.34 V, what is the standard reduction potential for the Ga3+/Ga half-cell?A) -1.34 VB) -0.56 VC) +0.56 VD) +1.36 V
Q:
What is the standard cell potential for the reaction below?Mg(s) + Br2(l) -> Mg2+(aq) + 2 Br-(aq)The standard reduction potential is -2.37 V for the Mg2+/Mg half-cell and +1.09 V for the Br2/Br- half-cell.A) -3.46 VB) -1.28 VC) +1.28 VD) +3.46 V
Q:
What is the relationship between the standard cell potentials, E, for the following two galvanic cell reactions?I. 2 Ag+(aq) + Sn2+(aq) -> Sn4+(aq) + 2 Ag(s)II. Ag(s) + 1/2 Sn4+(aq) -> 1/2 Sn2+(aq) + Ag+(aq)A) E(I) = E(II)B) E(I) = 2E(II)C) E(I) = - E(II)D) E(I) = - 2E(II)
Q:
What is the relationship between the standard cell potentials, E, for the following two galvanic cell reactions?I. 3 Cu2+(aq) + 2 Al(s) -> 3 Cu(s) + 2 Al3+(aq)II. 6 Cu2+(aq) + 4 Al(s) -> 6 Cu(s) + 4 Al3+(aq)A) E(I) = E(II)B) E(I) = E(II)C) E(I) = 2E(II)D) E(I) = E(II)2
Q:
Which is not true for standard electrode potentials?
A) Cell constituents are in their standard states.
B) E for oxidation is the negative of E for reduction.
C) The half-reactions are written as reductions.
D) The potential for the standard hydrogen electrode is chosen to be +1.00 V.
Q:
What is the relation between G and E for the cell reaction below?Ni2+(aq) + Cd(s) -> Cd2+(aq) + Ni(s)A) G = F EB) G = 2 F EC) G = -F ED) G = -2 F E
Q:
Doubling all the coefficients in the equation for the cell reactionA) doubles both E and G.B) doubles E, but does not change G.C) doubles G, but does not change E.D) does not change E or G.
Q:
The nickel-cadmium battery cell has a standard potential of +1.20 V. The cell reaction is2 NiO(OH)(s) + Cd(s) + 2 H2O(l) -> 2 Ni(OH)2(s) + Cd(OH)2(s).What is the standard free energy change for this reaction?A) -38.7 kJB) -116 kJC) -232 kJD) -463 kJ
Q:
For the reaction 2 Al(s) + 3 Co2+(aq) -> 2 Al3+(aq) + 3 Co(s), G is -799 kJ. What is E for a standard cell based on this reaction?A) +1.38 VB) +2.76 VC) +4.14 VD) +8.28 V
Q:
The cell reaction for a dry cell battery is The standard cell potential for this cell is 1.56 V. What is the standard free energy change for this cell?
A) +151 kJ
B) -151 kJ
C) -301 kJ
D) -602 kJ
Q:
In the relationship G = - nFE, what is the value of n for the reaction shown below?3 Cu2+(aq) + 2 Al(s) ->3 Cu(s) + 2 Al3+(aq)A) 1B) 2C) 3D) 6
Q:
What is the relation between joules (J), volts (V), and coulombs (C)?
A) 1 J = 1 V 1 C
B) 1 J = 1 V 1 C
C) 1 J = 1 C 1 V
D) 1 J = 1 V 1 C2
Q:
Write the overall cell reaction for the galvanic cell given below.D) No reaction would occur because there is no salt bridge.
Q:
For the galvanic cell , what is the function of the Pt(s)?A) Pt is the anode and is a reactant in the overall cell reaction.B) Pt is the anode and does not appear in the overall cell reaction.C) Pt is the cathode and is a product in the overall cell reaction.D) Pt is the cathode and does not appear in the overall cell reaction.
Q:
What is the balanced equation for the galvanic cell reaction expressed using shorthand notation below?
Q:
What is the balanced chemical equation for the galvanic cell reaction expressed using shorthand notation below?
Q:
3For the galvanic cell reaction, expressed below using shorthand notation, what half-reaction occurs at the anode?