Honors Chemistry Unit 4B - Predicting Products, Net Ionic Equations, & Redox Reactions

Synthesis (Combination) Reaction

Two or more reactants combine to form a single product.

General Formula for Synthesis Reactions

A + B → AB

Example of a Synthesis Reaction

Sodium reacts with chlorine gas to form sodium chloride (2Na + Cl₂ → 2NaCl).

Decomposition Reaction

A single reactant breaks down into two or more simpler substances.

General Formula for Decomposition Reactions

AB → A + B

Example of a Decomposition Reaction

Calcium carbonate decomposes into calcium oxide and carbon dioxide (CaCO₃ → CaO + CO₂).

Single Replacement Reaction

A more reactive element replaces a less reactive one in a compound.

General Formula for Single Replacement Reactions

A + BC → B + AC

Double Replacement Reaction

Two ionic compounds swap ions to form two new compounds.

General Formula for Double Replacement Reactions

AB + CD → AD + CB

Combustion Reaction

A hydrocarbon reacts with oxygen to produce CO₂ + H₂O.

General Formula for Combustion Reactions

CxHy + O₂ → CO₂ + H₂O

Net Ionic Equation

Shows only the reacting ions, removing spectator ions.

Steps to Determine Net Ionic Equation

1. Write the balanced equation. 2. Break aqueous compounds into ions. 3. Cancel spectator ions. 4. Write the final net ionic equation.

Oxidation

Loss of electrons (LEO = Lose Electrons Oxidation).

Reduction

Gain of electrons (GER = Gain Electrons Reduction).

Oxidation Number Rule for Pure Elements

Oxidation number is 0 (e.g., O₂, Na, Cl₂).

Oxidation Number Rule for Ions

Oxidation number is equal to the charge of the ion (e.g., Na⁺ = +1).

Balancing Redox Equations

Split into oxidation & reduction half-reactions, balance atoms & charge, and add together.

Example of Redox Reaction

MnO₄⁻ + 5Fe²⁺ + 8H⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O (balanced in acidic solution).