Exam 18: Electrochemistry

Calculate the cell potential for the following unbalanced reaction that takes place in an electrochemical cell at 25 °C when [ $\mathrm { Cr } ^ { 3 }$ ] = 0.945 M and [ $\mathrm { Zn } ^ { 2 + }$ ] = 1.37 M $\quad$$\quad$ Zn(s)+ $\mathrm { Cr } ^ { 3+ }$ (aq)? $\mathrm { Zn } ^ { 2 + }$ (aq)+ Cr(s) E°(Zn²⁺/Zn)= -0.76 V and E°(Cr³⁺/Cr)= -0.73 V

If the standard reduction potential of Zn is -0.76 V,which of the following statements about a cell whose half-cells are Zn²⁺/Zn and SHE is correct?

How many electrons are transferred in the following reaction? (The reaction is unbalanced.) $\quad$$\quad$ I₂(s)+ Fe(s)→ Fe³⁺(aq)+ I^- (aq)

Which of the following statements is true for the cell diagram below? $\quad$ Zn(s)| Zn²⁺(aq) $\|$ Cu²⁺(aq)| Cu(s)

Calculate the cell potential for the following unbalanced reaction that takes place in an electrochemical cell at 25 °C when [ $\mathrm { Mg } ^ { 2 + }$ ] = 1.10 M and [ $\mathrm { Fe } ^ { 3 + }$ ] = 1.10 M $\quad$$\quad$$\quad$ Mg(s)+ $\mathrm { Fe } ^ { 3 + }$ (aq)? $\mathrm { Mg } ^ { 2 + }$ (aq)+ Fe(s) E°(Mg²⁺/Mg)= -2.37 V and E°(Fe³⁺/Fe)= -0.036 V

Identify the components of a fuel cell.

The gas OF₂ can be produced from the electrolysis of an aqueous solution of KF,as shown in the equation below: $\quad$$\quad$ OF₂(g)+ 2H⁺(aq)+ 4 e^- → H₂O(l)+ 2F^-(aq)E° = +2.15 V Using 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 0.480 faradays through an aqueous KF solution.

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25 °C.(The equation is balanced.) $\quad$$\quad$ 3Cl₂(g)+ 2Fe(s)→ 6Cl^- (aq)+ 2Fe³⁺(aq) Cl₂(g)+ 2 e^- → 2Cl^- (aq) $\quad$$\quad$ E° = +1.36 V Fe³⁺(aq)+ 3 e^- → Fe(s) $\quad$$\quad$ E° = -0.04 V

Calculate the cell potential for the following unbalanced reaction that takes place in an electrochemical cell at 25 °C when [ $\mathrm { Cr } ^ { 3+ }$ ] = 2.00 M and [ $\mathrm { Zn } ^ { 2 + }$ ] = 0.00300 M $\quad$$\quad$ Zn(s)+ $\mathrm { Cr } ^ { 3+ }$ (aq)? $\mathrm { Zn } ^ { 2 + }$ (aq)+ Cr(s) E°(Zn²⁺/Zn)= -0.76 V and E°(Cr³⁺/Cr)= -0.73 V

Identify the metal if during a 1.000 hour long 2 electron electrolysis reaction 8.388 g of metal is deposited using a constant current of 4.000 A.

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25 °C: $\quad$$\quad$$\quad$ Sn(s)| Sn²⁺(aq,1.8 mol L^-1) $\|$ Ag⁺(aq,0.055 mol L^-1)| Ag(s) E°(Sn²⁺/Sn)= -0.14 V and E°(Ag⁺/Ag)= +0.80 V

Based on the following information, $\quad$$\quad$ Cl₂(g)+ 2 e^- → 2Cl^-(aq)E° = +1.36 V $\quad$$\quad$ Mg²⁺(aq)+ 2 e^- → 2Mg(s)E° = -2.37 V Which of the following chemical species is the strongest reducing agent?

Identify the characteristics of a spontaneous reaction.

Which of the following metals will dissolve in nitric acid but not hydrochloric acid?

How many seconds are required to produce 7.00 g of aluminum metal from the electrolysis of molten $\mathrm { AlCl } _ { 3 }$ with an electrical current of 18.0 A?

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25 °C.(The equation is balanced.) $\quad$$\quad$ 2K(s)+ I₂(s)→ 2K⁺ (aq)+ 2I^- (aq) K⁺(aq)+ e^- → K (s) $\quad$ E° = -2.93 V I₂(s)+ 2 e^- → 2 I^- (aq) $\quad$ E° = +0.54 V

How many electrons are transferred in the following reaction? (The reaction is unbalanced.) $\quad$$\quad$ Fe²⁺(aq)+ K(s)→ Fe(s)+ K⁺(aq)

Identify the battery type that has a high overcharge tolerance.

Use the provided reduction potentials to calculate the equilibrium constant (K)for the following balanced redox reaction at 25 °C: $\quad$$\quad$ 2Al(s)+ 3Mg²⁺(aq)→ 2Al³⁺(aq)+ 3Mg(s) E°(Al³⁺/Al)= -1.66 V and E°(Mg²⁺/Mg)= -2.37 V

Calculate the cell potential for the following unbalanced reaction that takes place in an electrochemical cell at 25 °C when [ $\mathrm { Mg } ^ { 2 + }$ ] = 0.914 M and [ $\mathrm { Fe } ^ { 3 + }$ ] = 0.0230 M $\quad$$\quad$ Mg(s)+ $\mathrm { Fe } ^ { 3 + }$ (aq)? $\mathrm { Mg } ^ { 2 + }$ (aq)+ Fe(s) E°(Mg²⁺/Mg)= -2.37 V and E°(Fe³⁺/Fe)= -0.036 V