Redox Reactions

Redox reactions are the last reactions we will study in this unit. It encompasses synthesis, decomposition, and single replacement reactions. It is categorized by all reactions that involve in a transfer of electrons.

• If the element/compound loses electrons, it is oxidized (because the charge becomes more positive)
• If the element/compound gains electrons it is reduced (because the charge becomes more negative)

Always Remember OIL RIG!!!

Oxidation Is Lost

Reduction Is Gained

OIL RIG

The "lost" and "gained" refers to the electrons

• Also, to make things more confusing, the compound/element being oxidized is referred to as the reducing agent
• The compound/element being reduced is referred to as the oxidizing agent
• Just think about what that compound/element is doing to the other compound/element
• To determine the oxidation number of the element use these rules:

Single Replacement:

• Always follows this structure:

• The completion of the reaction is based upon the reactivity of the elements

  

  If the element is less reactive than the element it is trying to "replace" in the reaction, the reaction will not be completed

• Nonmetals replace nonmetals and metals replace metals
• For example:

  

  The Fe (a metal) replaced the Cu (a metal) to create FeSO4
  
  

Synthesis:

• Follows this structure:

• For example:

The H2 combines with the O2 to form H2O

Decomposition:

• Follows this structure:
  
• For example: 

  

  The H2O decomposes into H2 and O2

Bozeman Science Redox Reactions Video