Redox Reactions

• What is a redox reaction?

  A redox reaction is a chemical reaction in which there is a transfer of electrons between reactants, resulting in a change in oxidation states.
• What is oxidation?

  Oxidation is a chemical reaction in which a substance loses electrons. (OIL)
• What is reduction?

  Reduction involves the gain of electrons. (RIG)
• What is an oxidising agent?

  An oxidant is a reductant that causes another reactant to lose electrons.
• What is a reducing agent?

  Is a reactant that causes another reactant to gain electrons.
• Predictions for Group 1 & 2 metals?

  Are oxidised and are reducing agents as they donate their valnence electrons more readily.
• Predict the redox reactions of group 17 metals.

  They gain electrons to form more stable electrons. The halogens are reduced and act as oxidising agents.
• What is the displacement reactions of metals?

  Often called single displacement reactions. Single displacement reactions occur when a stronger reducing agent replaces a weaker reducing agent.
• What is a combustion reaction?

  A chemical reaction that involves the rapid combination of a fuel with oxygen, resulting in the release of heat and the formation of new products.
• What are corrosion reactions?

  Chemical reactions that degrade materials, typically metals, due to exposure to environmental factors like oxygen or moisture.
• What is an oxidation number?

  Indicates the number of electrons lost or gained by an atom. Is written sign before number. Will increase when oxidised and decrease when reduced.
• What are the oxidation states of transition metals?

  Can have multiple oxidation states. When determining their oxidation numbers if there is no atom then its oxidation number must be determined by the other atoms.
• What is E*?

  Standard reduction potentials?
• What does a high negative E* mean?

  Strongest reductants?
• What does a high positive E* mean?

  Strongest oxidant.
• What is a spontaneous reaction?

  Requires no input of energy for the reaction to occur.
• What is a non-spontaneous reaction?

  Require energy to be added to the system for the reaction to occur.
• What is an electrochemical cell?

  Converts chemical energy into electrical energy.
• What is a galvanic cell?

  Contains a spontaneous redox reaction that produces electrical energy.
• What is an electrode?

  The anode is where oxidation occurs and the cathode where reduction occurs.
• What is the external circuit?

  Electrons are produced at the negative anode, and then move through the external circuit to the cathode where they are consumed.
• What is the salt bridge?

  An internal circuit that allows flow of ions between the two beakers.
• What is the hydrogen half cell?

  The position of all the half-equations in the electrochemical series are measured by connecting them to a hydrogen half cell. This determines whether a half-equation contains a stronger oxidant or reductant than the hydrogen cell.
• EMF = E*reduction - E*oxidation
• What are the standard lab conditions?

  25*C, 1 atm, and 1M of ionic solution.
• What is a separator?

  In a battery it prevents the reactants from spontaneously reacting with one another.
• What are button cells?

  Are much smaller than alkaline cells that can be used in very small electrical devices such as watches. Contains a zinc anode, alkaline electrolyte, and a cathode.
• What is a fuel cell?

  An alternate way of producing an electrical current. Is a constant supply of reactants and inert electrodes that cannot break down.
• What is an alkaline fuel cell?

  Are hydrogen-oxygen fuel cells.