Electrochemistry Module 1 Quiz
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Questions and Answers

What occurs during galvanic corrosion?

  • It happens when a metal is exposed to air.
  • It involves different metals in contact with each other in electrolyte. (correct)
  • Corrosion occurs exclusively at the edges of a metal.
  • Corrosion occurs evenly over a large surface area of a metal.
  • In a redox reaction, which species is oxidized?

  • The species that loses electrons. (correct)
  • The species that remains unchanged.
  • The species that has the highest standard electrode potential.
  • The species that gains electrons.
  • What does a higher standard reduction potential indicate?

  • It does not affect the redox reaction.
  • A stronger ability to gain electrons. (correct)
  • A weaker ability to gain electrons.
  • A stronger ability to lose electrons.
  • In the electrolysis of silver nitrate (AgNO3), which reaction at the cathode is expected?

    <p>Ag+ + 2e- → Ag(s)</p> Signup and view all the answers

    What characterizes crevice corrosion?

    <p>It occurs in small gaps or crevices between two pieces of metal.</p> Signup and view all the answers

    What is the role of Cu in the redox reaction with Ag+?

    <p>Cu is oxidized to Cu^2+ and facilitates the reduction of Ag+.</p> Signup and view all the answers

    What flow occurs in a galvanic cell to balance charge due to reduction?

    <p>NH4+ flows into the Ag+ beaker.</p> Signup and view all the answers

    Which statement is true about the electrolysis process?

    <p>It can produce gases or deposit metals.</p> Signup and view all the answers

    What is the role of the anode in a galvanic cell?

    <p>It is where oxidation occurs.</p> Signup and view all the answers

    What is denoted by a double vertical line in cell notation?

    <p>Salt bridge</p> Signup and view all the answers

    How is the standard electrode potential determined for a half-cell?

    <p>It is based on the comparison with a chosen standard electrode.</p> Signup and view all the answers

    Which of the following compounds acts as the anode in a lithium-manganese dioxide battery?

    <p>Lithium</p> Signup and view all the answers

    What does the equation $E^\circ = E^\circ_{anode} - E^\circ_{cathode}$ represent?

    <p>Standard cell potential calculation</p> Signup and view all the answers

    What is the significance of standard reduction potentials?

    <p>They indicate the voltage produced under standard conditions.</p> Signup and view all the answers

    What does a phase boundary represent in cell notation?

    <p>Transition between different states of matter</p> Signup and view all the answers

    In galvanic cells, cell potentials behave like which type of functions?

    <p>State functions</p> Signup and view all the answers

    What is one of the reactants used in a zinc-air battery?

    <p>Oxygen from the surrounding air</p> Signup and view all the answers

    Which of the following describes nickel-metal-hydride batteries?

    <p>They are designed for rechargeable use.</p> Signup and view all the answers

    In a lead-acid battery, which material is used as the anode?

    <p>Lead metal</p> Signup and view all the answers

    What type of electrolysis involves electrodes that are chemically inert materials?

    <p>Passive electrolysis</p> Signup and view all the answers

    What occurs during the reaction represented by $H_2 → 2H^+ + 2e^-$?

    <p>Oxidation</p> Signup and view all the answers

    Which of the following reactions occurs in active electrolysis?

    <p>Electrolytic reactions where electrodes participate</p> Signup and view all the answers

    Which of the following pairs is incorrectly matched regarding battery components?

    <p>Cathode - Nickel oxide (nickel-metal-hydride battery)</p> Signup and view all the answers

    What characteristic does lithium possess that makes it advantageous in batteries?

    <p>Large standard reduction potential</p> Signup and view all the answers

    Study Notes

    Types of Corrosion

    • Uniform corrosion occurs evenly over a large surface area of metal.
    • Galvanic corrosion happens when two different metals are in contact in an electrolyte.
    • Crevice corrosion arises in small gaps between touching metal pieces.

    Oxidation-Reduction Reactions

    • Oxidation is defined as the loss of electrons; reduction is the gain of electrons.
    • Silver ion reduction example:
      • ( \text{Ag}^+ + e^- \rightarrow \text{Ag(s)} )
    • Copper oxidation example:
      • ( \text{Cu(s)} \rightarrow \text{Cu}^{2+} + 2e^- )

    Galvanic Cells

    • Oxidation occurs at the anode; reduction occurs at the cathode.
    • NH4+ ions flow to offset silver ions removed, while Cl- ions offset copper ions produced.
    • Cell notation format:
      • Left side includes anode and right side includes cathode, e.g., ( \text{Cu(s)} | \text{Cu}^{2+} (1 \text{ M}) || \text{Ag}^+ (1 \text{ M}) | \text{Ag(s)} ).

    Measuring Cell Potentials

    • Standard Hydrogen Electrode (SHE) is assigned zero volts.
    • All other half-cells are measured against this reference.

    Standard Reduction Potentials

    • Standard reduction potentials are crucial for calculating cell potentials and predicting reaction spontaneity.
    • ( E^{\circ}{cell} = E^{\circ}{cathode} - E^{\circ}_{anode} )

    Batteries

    • Primary cells include lithium and alkaline batteries; characterized by non-rechargeability.
    • Secondary cells (e.g. nickel-metal-hydride) can be recharged and include lead-acid batteries regularly found in vehicles.

    Fuel Cells and Electrolysis

    • Fuel cells convert chemical energy to electrical energy efficiently.
    • Electrolysis can be passive (inert electrodes) or active (reacting electrodes).

    Electrolysis Processes

    • Example of electrolysis for silver plating:
      • ( \text {Ag(s)} + 2 \text {CN}^- \right arrow \text {Ag(CN)} ^- + e^- )
    • Current, charge, and time relation:
      • Faraday's law correlates current to the amount of substance deposited.

    Engineering Design Considerations

    • Lithium-ion batteries benefit from high standard reduction potential of Li^+/Li.
    • Both lithium and carbon materials are lightweight, optimizing energy density.

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    Description

    Test your knowledge on corrosion types and the chemical reactions responsible for them. This quiz covers redox processes, balancing half-reactions, and calculating cell potentials under various conditions. Assess your understanding of electrochemistry principles essential for engineers.

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