CHEM 210 Exam 4 Advanced Practice Questions and Answers | 100% Pass Guaranteed | Graded A+

1



CHEM 210 Exam 4 Advanced Practice Questions and
Answers | 100% Pass Guaranteed | Graded A+


1. In an electrochemical cell, the electrode where oxidation occurs is called the:


A. Cathode


B. Anode


C. Salt bridge


D. Electrolyte


☑ Correct Answer: B


☑ Explanation: The anode is the electrode where oxidation takes place (loss of

electrons). The cathode is where reduction occurs (gain of electrons). The salt bridge


maintains ionic balance, and the electrolyte conducts ions. Option A is for reduction.


Options C and D are cell components, not electrodes.




2. The standard reduction potential (E°) for the half-reaction Cu2+(aq) + 2e- → Cu(s) is


+0.34 V. Which of the following statements is true?


A. Cu2+ is a strong reducing agent.

,2


B. Cu is a strong oxidizing agent.


C. Cu2+ is a weak oxidizing agent.


D. Cu is a weak reducing agent.


☑ Correct Answer: C


☑ Explanation: A positive standard reduction potential indicates that the species

(Cu2+) is easily reduced, meaning it is a good oxidizing agent. Since +0.34 V is moderate,


Cu2+ is a weak oxidizing agent compared to stronger ones like F2 or MnO4-. Cu (the


reduced form) is a weak reducing agent. Option A is incorrect because Cu2+ is an


oxidizing agent, not a reducing agent. Option B is incorrect because Cu is the reduced


form and is a reducing agent. Option D is partially true but less directly related to the


reduction potential. The most accurate statement is that Cu2+ is a weak oxidizing agent.




3. A voltaic cell is constructed with a zinc electrode in Zn2+ solution and a copper


electrode in Cu2+ solution. The standard reduction potentials are: Zn2+ + 2e- → Zn(s) E°


= -0.76 V; Cu2+ + 2e- → Cu(s) E° = +0.34 V. What is the standard cell potential (E°cell)?


A. -0.42 V


B. +0.42 V

,3


C. +1.10 V


D. -1.10 V


☑ Correct Answer: C


☑ Explanation: The cell potential is E°cell = E°cathode - E°anode. The cathode is

where reduction occurs (Cu2+ + 2e- → Cu(s), E° = +0.34 V). The anode is where oxidation


occurs (Zn(s) → Zn2+ + 2e-, E° = -0.76 V). E°cell = 0.34 V - (-0.76 V) = 1.10 V. Option A is


the sum with wrong sign. Option B is incorrect. Option D is incorrect.




4. In a galvanic cell, the salt bridge serves to:


A. Provide a source of electrons


B. Complete the circuit and maintain electrical neutrality


C. Act as the cathode


D. Act as the anode


☑ Correct Answer: B


☑ Explanation: The salt bridge completes the electrical circuit by allowing ions to

flow between the two half-cells, maintaining electrical neutrality. It does not provide

, 4


electrons (the electrodes do that). It does not act as an electrode. Option A is incorrect.


Options C and D are incorrect.




5. The Nernst equation relates the cell potential to the concentrations of the reactants and


products. For the reaction Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s), the Nernst equation is:


A. E = E° - (RT/nF) ln Q


B. E = E° + (RT/nF) ln Q


C. E = E° - (RT/nF) log Q


D. E = E° + (RT/nF) log Q


☑ Correct Answer: A


☑ Explanation: The Nernst equation is E = E° - (RT/nF) ln Q, where Q is the reaction

quotient. For this reaction, Q = [Zn2+]/[Cu2+]. Option B has the wrong sign. Options C


and D use log instead of ln and have wrong signs.




6. A voltaic cell has a cell potential of 0.80 V. If the reaction quotient, Q, is 10, and n = 2,


what is the cell potential at 298 K? (R = 8.314 J/mol·K, F = 96485 C/mol)