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Fundamentals of Electrolysis quiz

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  • What is electrolysis?
    Electrolysis is the process of passing an electrical current through a substance to produce chemical changes.
  • Are electrolysis reactions spontaneous or non-spontaneous?
    Electrolysis reactions are non-spontaneous and require external energy to occur.
  • What is a common example of electrolysis?
    A common example is the decomposition of water into oxygen and hydrogen gases using an electric current.
  • What unit is electrical current measured in?
    Electrical current is measured in amperes (amps).
  • What is the relationship between amperes and coulombs per second?
    One ampere is equal to one coulomb per second.
  • What is the formula relating current, charge, and time?
    The formula is I = Q/T, where I is current, Q is charge, and T is time.
  • How do you calculate moles of electrons in an electrolysis reaction?
    Moles of electrons = (current × time) / Faraday's constant.
  • What is Faraday's constant used for in electrolysis calculations?
    Faraday's constant is used to relate the total charge passed to the number of moles of electrons.
  • What is the sign of the cell potential for non-spontaneous processes?
    The cell potential is negative (less than 0) for non-spontaneous processes.
  • What is ohmic potential in electrolysis?
    Ohmic potential is the voltage needed to overcome the resistance in the circuit when current is flowing.
  • How is current related to voltage and resistance in electrolysis?
    Current (I) equals voltage (E) divided by resistance (R), or I = E/R.
  • What is overpotential in the context of electrolysis?
    Overpotential is the extra voltage required to overcome the activation energy for a reaction at the electrode.
  • What is concentration polarization?
    Concentration polarization occurs when there is a difference in reactant concentration at the electrode surface compared to the bulk solution.
  • How do ohmic potential, overpotential, and concentration polarization affect cell potential?
    They make the overall cell potential more negative, increasing the energy required to drive the reaction.
  • Why is an external current necessary in electrolysis?
    An external current is necessary because the process is non-spontaneous and will not occur naturally without added energy.