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Redox Reactions quiz #2

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Termini in questo insieme (35)

  • How can you identify a redox reaction?
    A reaction where oxidation numbers of elements change is a redox reaction.
  • In which reaction does the oxidation number of oxygen increase?
    A reaction where oxygen loses electrons and its oxidation number becomes more positive.
  • What reaction reduces oxygen to form water?
    A reaction where oxygen gains electrons and forms H2O, such as O2 + 4e- + 4H+ → 2H2O.
  • Which half-reaction correctly represents reduction?
    A half-reaction where a species gains electrons, such as Fe3+ + e- → Fe2+, represents reduction.
  • What happens in redox reactions?
    Electrons are transferred between reactants, resulting in changes in oxidation states.
  • By what substances can H2 (g) be oxidized?
    H2 can be oxidized by a substance that acts as an oxidizing agent, such as O2 or Cl2.
  • What happens to a reducing agent during a redox reaction?
    The reducing agent is oxidized; it loses electrons.
  • Which reaction is not an example of an oxidation–reduction reaction?
    A reaction where no electron transfer or change in oxidation states occurs is not a redox reaction.
  • Which type of equation can represent the oxidation occurring in a reaction?
    An oxidation half-reaction equation, showing electron loss, represents oxidation.
  • What is an example of oxidation?
    A process where a species loses electrons, such as Fe → Fe2+ + 2e-, is an example of oxidation.
  • What is the difference between oxidation and reduction?
    Oxidation is the loss of electrons (increase in oxidation number); reduction is the gain of electrons (decrease in oxidation number).
  • The presence of which reactant is the best indicator of an oxidation-reduction reaction?
    A reactant whose oxidation state changes during the reaction indicates a redox reaction.
  • In the presence of what does hydrogen peroxide decompose?
    Hydrogen peroxide decomposes in the presence of a catalyst, often a transition metal, via a redox reaction.
  • Which metal(s) can be oxidized with a Pb2+ solution but not with a Cd2+ solution?
    Metals with reduction potentials between those of Pb2+ and Cd2+ can be oxidized by Pb2+ but not by Cd2+.
  • What acts as the reductant in the reaction H2(g) + Cl2(g) → 2HCl(g)?
    H2 acts as the reductant (reducing agent) because it is oxidized.
  • What does the equation represent? Ca → Ca2+ + 2e-
    This equation represents the oxidation of calcium.
  • What type of battery uses the reaction Zn(s) + 2 MnO2(s) → ZnO(s) + Mn2O3(s)?
    This reaction occurs in a dry cell (alkaline) battery, which is based on redox chemistry.
  • Which substance is the reducing agent in this reaction? Cr2O7^2- + 3 HNO2 + 5 H+ → 2 Cr^3+ + 3 NO3^- + 4 H2O
    HNO2 is the reducing agent because it is oxidized.
  • What happens to iron when it is oxidized from Fe0 to Fe2+ ions?
    Iron loses two electrons, increasing its oxidation number from 0 to +2.
  • Whenever a molecule is oxidized, another molecule must be reduced.
    True; oxidation and reduction always occur together in a redox reaction.
  • A molecule becomes more oxidized when it __________.
    A molecule becomes more oxidized when it loses electrons.
  • A molecule becomes more oxidized when it
    Loses electrons and its oxidation number increases.
  • A molecule becomes oxidized when it __________.
    Loses electrons.
  • Oxidation and reduction always occur simultaneously and are referred to as a(n) __________ reaction.
    Redox reaction.
  • The purpose(s) of flux on an electrode is/are:
    To facilitate electron transfer and prevent unwanted side reactions during redox processes.
  • A molecule that functions as the electron donor in a redox reaction __________.
    Is the reducing agent and is oxidized.
  • Redox reactions involve the gain or loss of _____.
    Electrons.
  • When a compound is oxidized it ______ one or more electrons.
    Loses.
  • When oxygen accepts electrons, water is produced as a byproduct.
    True; oxygen is reduced and forms water in many redox reactions.
  • Which balanced equation represents a redox reaction?
    An equation where oxidation numbers change, such as 2Na + Cl2 → 2NaCl.
  • Is the reaction shown an oxidation, reduction, or neither?
    If a species loses electrons, it is oxidation; if it gains electrons, it is reduction; if neither occurs, it is neither.
  • During the electrolysis of molten NaI, what reaction occurs at the anode?
    At the anode, iodide ions are oxidized to iodine: 2I- → I2 + 2e-.
  • If a compound is reduced, what is the result?
    Its oxidation number decreases as it gains electrons.
  • A reaction that involves the transfer of electrons from one molecule to another is referred to as
    A redox (oxidation-reduction) reaction.
  • Determine whether each change represents oxidation or reduction.
    If a species loses electrons, it is oxidation; if it gains electrons, it is reduction.