Electrochemistry Review

AlF₆ ^3– + 3 e^– → Al + 6 F^{– 1}

Which of the following occurs in the reaction?

• AlF₆^3– is reduced at the cathode.

• Al is oxidized at the anode.

• Aluminum is converted from the –3 oxidation state to the 0 oxidation state.

• Aluminum is converted from the –3 oxidation state to the 0 oxidation state.

Tags

NGSS.HS-PS1-2

AlF₆ ^3– + 3 e^– → Al + 6 F^{– 1}

A steady current of 10 amperes is passed though an aluminum-production cell for 15 minutes. Which of the following is the correct expressions for calculating the number of grams of aluminum produced? (1 faraday = 96,500 coulombs)

• 
• 
• 
• 

Tags

NGSS.HS-PS1-7

Fe²⁺ + 2e^– → Fe(s) E° = –0.44 volt

Ni²⁺ + 2e^– → Ni(s) E° = –0.23 volt

The standard reduction potentials for two half reactions are given above. The Nernst equation for a galvanic cell at 25°C in which Fe(s) reduces Ni²⁺ is the following.

E = E° – 0.03 log [Fe²⁺]/[Ni²⁺]

What is the equilibrium constant for the reaction below?

Fe(s) + Ni²⁺ → Fe²⁺ + Ni(s)

• 1.9 × 10^–23

• 7.6 × 10^–8

• 3.6 × 10³

• 1.3 × 10⁷

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-6

Which of the following best represents a reaction in which the same reactant undergoes both oxidation and reduction?

• S₈(s) + 8 O₂(g) → 8 SO₂(g)

• H₂SeO₄(aq) + 2 Cl^–(aq) + 2 H⁺(aq) → H₂SeO₃(aq) + Cl₂(g) + H₂O(l)

• 3 Br₂(aq) + 6 OH^–(aq) → 5 Br^– (aq) + BrO₃ ^– (aq) + 3 H₂O(l)

• PtCl₄(s) + 2 Cl^– (aq) → PtCl₆^2– (aq)

Tags

NGSS.HS-PS1-2

A redox reaction has an equilibrium constant of

K = 2.6 x 10⁵. Which of the following statements best represents the algebraic signs of E^o_cell and G^o_rxn for this reaction?

• E^o_cell is positive and G^o_rxn is positive.

• E^o_cell is negative and G^o_rxn is negative.

• E^o_cell is positive and G^o_rxn is negative.

• E^o_cell is negative and G^o_rxn is positive.

Which of the following statements applies to the change in mass of the electrodes involved in this electrochemical cell?

• Electrode A is the anode and it gains mass

  since metal ions are being converted to metal

  atoms which often adhere to the electrode.

• Electrode B is the anode and it gains mass

  since metal ions are being converted to metal

  atoms which often adhere to the electrode.

• Electrode A is the cathode and it gains mass since metal ions are being converted to metal atoms which often adhere to the electrode.

• Electrode B is the cathode and it gains mass since metal ions are

  being converted to metal atoms which often adhere to the electrode.

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

Which of the following best describes this electrochemical cell?

• Electrode A is the anode since anions are present in its half-cell and the current flows from cathode to anode.

• Electrode C is the cathode since cations are present in its half-cell and the current flows from anode to cathode.

• Electrode A is the anode and Electrode C is the cathode since the current always flows from cathode to anode.

• Electrode C is the anode and Electrode A is the cathode since the current always flows from anode to cathode.

Which of the following best describes the function of the portion of the electrochemical cell labeled B?

• Structure B functions to complete the electrical circuit present in the electrolytic cell.

• Structure B provides soluble anions that migrate to the anode as well as soluble cations that migrate to the cathode, thus maintaining a balance of charge in the electrolytic cell.

• Structure B provides soluble anions that migrate to the anode as well as soluble cations that migrate to the cathode, thus maintaining a balance of charge in the galvanic cell.

• Structure B provides soluble anions that migrate to the cathode as well as soluble cations that migrate to the anode, thus maintaining a charge balance in the galvanic cell.

A student wishes to construct a thermodynamically favorable galvanic cell using electrodes made of chromium and silver. Each half cell will consist of the electrode partially submerged in a 1.0 M solutions of its nitrate salt. The two electrodes will be connected by separate wires to a voltmeter and the two half-cells will be connected with a salt bridge.

Which of the following best represents the

initial reading on the voltmeter?

• –0.13 V

• –1.53 V

• 1.53 V

• 3.13 V

Tags

NGSS.HS-PS2-5

A student wishes to construct a thermodynamically favorable galvanic cell using electrodes made of chromium and silver. Each half cell will consist of the electrode partially submerged in a 1.0 M solutions of its nitrate salt. The two electrodes will be connected by separate wires to a voltmeter and the two half-cells will be connected with a salt bridge.

Which metal serves as the anode in the student’s

thermodynamically favorable galvanic cell using electrodes

made of chromium and silver?

• Ag since reduction takes place in that half-cell.

• Ag since oxidation takes place in that half-cell.

• Cr since reduction takes place in that half-cell.

• Cr since oxidation takes place in that half-cell.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2