redox

• What acronym is used to help understand oxidation and reduction?

  OIL RIG
• What does oxidation refer to in terms of electrons?

  Oxidation is the loss of electrons
• What does reduction refer to in terms of electrons?

  Reduction is the gain of electrons
• What is a redox reaction?

  • A reaction involving both oxidation and reduction
  • Electrons are transferred between elements
• In the reaction involving calcium and oxygen, what happens to calcium?


  Calcium is oxidized as it loses electrons
• What happens to oxygen in the reaction with calcium?

  Oxygen is reduced as it gains electrons
• What is a reducing agent?

  A reducing agent is a substance that loses electrons and oxidizes itself
• In the reaction discussed, what is the reducing agent?

  Calcium
• What is an oxidizing agent?

  An oxidizing agent is a substance that gains electrons and is reduced
• In the reaction discussed, what is the oxidizing agent?

  Oxygen
• What are oxidation numbers?

  • Assigned to each element in a compound
  • Indicates the degree of oxidation or reduction
  • Follows a set of rules with some exceptions
• What is the oxidation number of uncombined elements?

  Always zero
• What is the oxidation number of an ion?


  The oxidation number is the same as the charge on the ion
• What is the oxidation number of Group 1 elements?

  Always +1
• What is the oxidation number of Group 2 elements?

  Always +2
• What is the oxidation number of aluminum?

  Always +3
• What is the oxidation number of hydrogen in most compounds?

  Always +1
• What is the exception for the oxidation number of hydrogen?

  In hydrides, hydrogen has an oxidation number of -1
• What is the oxidation number of chlorine in KCl?

  • 1
• What is the oxidation number of chlorine in ClF₃?

  +3
• What is the oxidation number of fluorine?

  Always -1
• What is the oxidation number of oxygen in most compounds?

  • 2
• What is the exception for the oxidation number of oxygen?

  In peroxides, oxygen has an oxidation number of -1
• How do you determine the oxidation states in a compound?

  1. Identify the most electronegative element.
  2. Assign oxidation numbers based on established rules.
  3. Ensure the total oxidation states equal the overall charge of the compound.
• What is the oxidation state of iron in FeO?

  +2
• What is the significance of oxidation states in transition metals?

  Transition metals can have variable oxidation states
• What is the importance of balancing oxidation states in a reaction?

  To ensure the overall charge of the molecule is neutral
• What is the role of electronegativity in determining oxidation states?

  The most electronegative element takes priority in assigning oxidation states
• What is the oxidation state of iron in iron(III) oxide?

  +3
• How do Roman numerals indicate the oxidation state of an element in a compound?

  Roman numerals represent the charge of the element in the compound.
• What is the formula for iron(II) oxide?

  FeO
• Why does iron have different oxidation states in its compounds?

  Iron can lose different numbers of electrons, resulting in different oxidation states.
• What is the oxidation state of vanadium in vanadium(IV) oxide?

  +4
• How do you determine the oxidation state of vanadium in vanadium(V) oxide?

  By balancing the total charge with the known oxidation state of oxygen, which is -2.
• What is the definition of oxidation in terms of oxidation number?

  Oxidation is an increase in oxidation number.
• What is reduction in terms of oxidation number?

  Reduction is a decrease in oxidation number.
• In the reaction 2 Na + Cl₂ → 2 NaCl, what happens to sodium's oxidation state?

  Sodium's oxidation state increases from 0 to +1.
• What role does sodium play in the reaction with chlorine?

  Sodium acts as a reducing agent because it is oxidized.
• What is a half equation in redox reactions?

  A half equation shows either the oxidation or reduction process and must include electrons.
• What are the steps to balance a half equation?

  1. Write down the species before and after the reaction.
  2. Balance atoms apart from oxygen and hydrogen.
  3. Balance oxygens with water (H₂O).
  4. Balance hydrogens with H⁺ ions.
  5. Balance charges with electrons.