redox

• What acronym can help remember the concepts of oxidation and reduction?

  The acronym is OIL RIG, which stands for Oxidation Is Loss, Reduction Is Gain.
• What happens to electrons during oxidation?

  Electrons are lost during oxidation.
• What happens to electrons during reduction?

  Electrons are gained during reduction.
• In the reaction of calcium with oxygen, what is calcium undergoing?

  Calcium is being oxidized because it is losing electrons.
• What is the charge of calcium after it loses electrons in the reaction with oxygen?

  The charge of calcium becomes +2 after losing two electrons.
• What is the role of oxygen in the reaction with calcium?

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

  A reducing agent is a substance that loses electrons and is oxidized itself.
• What is an oxidizing agent?

  An oxidizing agent is a substance that gains electrons and is reduced itself.
• What is the oxidation state of uncombined elements?

  The oxidation state of uncombined elements is always zero.
• How is the oxidation number of an ion determined?

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

  The oxidation number of Group 1 elements is always +1.
• What is the oxidation number of Group 2 elements?

  The oxidation number of Group 2 elements is always +2.
• What is the oxidation number of aluminum?

  The oxidation number of aluminum is always +3.
• What is the oxidation number of hydrogen in most compounds?

  The oxidation number of hydrogen is usually +1, except in hydrides where it is -1.
• What is the oxidation number of chlorine in KCl?

  The oxidation number of chlorine in KCl is -1.
• What is the oxidation number of chlorine in ClF3?

  The oxidation number of chlorine in ClF3 is +3.
• What is the oxidation number of fluorine?

  The oxidation number of fluorine is always -1.
• What is the oxidation number of oxygen in most compounds?

  The oxidation number of oxygen is usually -2, except in peroxides where it is -1.
• What is the oxidation number of oxygen in hydrogen peroxide (H2O2)?

  The oxidation number of oxygen in hydrogen peroxide is -1.
• How do you determine the oxidation state of sulfur in H2SO4?

  Oxygen is -2, hydrogen is +1, so sulfur must be +6 to balance the overall charge to zero.
• What is the oxidation state of sulfur in SO4^{2-}?

  The oxidation state of sulfur is +6 to balance the overall charge of -2.
• How do you determine the oxidation state of iron in Fe2O3?

  Oxygen is -2, so with three oxygens, the total is -6, making iron +3 to balance the charge.
• What is the oxidation state of iron in iron(II) oxide?

  The oxidation state of iron in iron(II) oxide is +2.
• How do you determine the oxidation state of vanadium in vanadium(IV) oxide?

  Oxygen is -2, so with two oxygens, the total is -4, making vanadium +4 to balance the charge.
• What are the key rules for assigning oxidation numbers?

  1. Uncombined elements have an oxidation number of 0.
  2. The oxidation number of an ion is the same as its charge.
  3. Group 1 elements are always +1.
  4. Group 2 elements are always +2.
  5. Aluminum is always +3.
  6. Hydrogen is usually +1, except in hydrides where it is -1.
  7. Chlorine is usually -1, except when bonded to fluorine or oxygen.
  8. Fluorine is always -1.
  9. Oxygen is usually -2, except in peroxides where it is -1.
• What are the differences between reducing agents and oxidizing agents?

  • Reducing agents:
  • Lose electrons
  • Are oxidized themselves
  • Oxidizing agents:
  • Gain electrons
  • Are reduced themselves
• What are the exceptions to the oxidation number rules?

  • Hydrogen is +1 except in hydrides where it is -1.
  • Chlorine is -1 except when bonded to fluorine or oxygen.
  • Oxygen is -2 except in peroxides where it is -1.
• How do you calculate oxidation states in compounds?

  1. Identify the oxidation numbers of known elements.
  2. Set up an equation to balance the total charge.
  3. Solve for the unknown oxidation state.
• What is the significance of oxidation states in redox reactions?

  • Oxidation states help track electron transfer.
  • They indicate the degree of oxidation or reduction of an element.
• 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 name of the compound with the formula FeO?

  Iron(II) oxide
• Why does iron have different oxidation states in its compounds?

  Iron can lose different numbers of electrons, leading to 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.
• What role does sodium play in the reaction with chlorine?

  Sodium acts as a reducing agent because it is oxidized.
• What is the role of chlorine in the reaction with sodium?

  Chlorine acts as an oxidizing agent because it is reduced.
• What are the steps to balance half equations?

  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.