12chem

    Cards (25)

    • What is bioluminescence?

      Bioluminescence is the conversion of potential energy in chemical bonds into light during a redox reaction.
    • How do fireflies produce light?
      Fireflies produce light from the oxidation of the molecule luciferin.
    • What is a common feature of deep-sea fishes and some jellyfish regarding light emission?
      They can control the light they emit.
    • What is the role of bioluminescent bacteria in some organisms?
      Some organisms harbor bioluminescent bacteria to produce light.
    • What happens during an oxidation reaction?
      An atom or ion loses electrons, and its oxidation number increases.
    • What occurs during a reduction reaction?

      An atom or ion gains electrons, and its oxidation number decreases.
    • What principle is the oxidation-number method based on?

      The principle that the total mass and charge are conserved in a chemical reaction.
    • What is a species in the context of chemical reactions?
      A species is any chemical unit involved in a process.
    • What is a reducing agent?
      A reducing agent is a species that can give up electrons.
    • What is an oxidizing agent?
      An oxidizing agent is a species that can accept electrons.
    • What does a half-reaction represent in a redox reaction?
      A half-reaction represents either the oxidation or reduction part of a redox reaction.
    • What happens to iron in the oxidation process?
      Each iron atom is oxidized by losing three electrons to become a Fe3+^{3+} ion.
    • What happens to chlorine in the reduction process?
      Each chlorine atom in Cl is reduced by accepting one electron to become a Cl^{-} ion.
    • What are the steps involved in the oxidation-number method for balancing redox equations?
      • Assign oxidation numbers to all species.
      • Identify which species are oxidized and reduced.
      • Make the number of electrons lost equal to the number of electrons gained.
      • Balance the increase and decrease in oxidation numbers.
      • Ensure the equation is balanced in terms of mass and charge.
    • Why can some redox reactions be difficult to balance?

      Because elements might appear more than once on each side of the equation.
    • What is produced from the reduction of nitrate ions in the reaction between copper and nitric acid?
      The brown gas produced is nitrogen dioxide (NO2_{2}).
    • What is the result of the oxidation of copper in the reaction with nitric acid?
      The oxidation of copper results in the formation of copper ions (Cu2+^{2+}).
    • What is the advantage of using a net ionic equation to represent a redox reaction?
      • Spectator ions are eliminated.
      • Shows only the substances that change during the reaction.
      • Simplifies the representation of the redox process.
    • What should be added to balance equations in an acidic solution?
      Hydrogen ions (H+^{+}) and/or water molecules can be added.
    • What should be added to balance equations in a basic solution?
      Hydroxide ions (OH^{-}) or water molecules can be added.
    • Why is it important to know whether a reaction occurs in an acidic or basic solution when balancing an ionic redox equation?
      Because the method of balancing oxygen atoms differs between acidic and basic solutions.
    • What is the due date for the homework related to balancing redox equations?
      The due date is Sunday, 15th of September.
    • What is the due date for the homework related to balancing net ionic redox equations?
      The due date is Thursday, 26th of September.
    • What is the learning objective of the copper sulfate and iron reaction experiment?

      To observe and understand the chemical reaction between copper sulfate and iron, and to learn about the oxidation-reduction process involved.
    • What materials are needed for the copper sulfate and iron reaction experiment?
      Copper sulfate (CuSO<latex>_{4}</latex) solution, iron nails, beaker, stirring rod, safety goggles, and gloves.
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