Comprehensive Guide to Classification of Chemical Transformations

Chemical Reaction

Involves breaking intramolecular bonds and forming new ones, resulting in new substances.

Synthesis (Combination)

A reaction where two or more substances combine to form a single product.

General Form of Synthesis Reaction

A + B → AB.

Example of Synthesis Reaction

Formation of ammonia: N2(g) + 3H2(g) → 2NH3(g).

Decomposition Reaction

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

General Form of Decomposition Reaction

AB → A + B.

Example of Decomposition Reaction

Decomposition of Hydrogen Peroxide: 2H2O2(aq) → 2H2O(l) + O2(g).

Combustion Reaction

A reaction where a substance reacts with oxygen, releasing energy.

Hydrocarbon Combustion Products

Always produces carbon dioxide (CO2) and water vapor (H2O).

Double Replacement (Metathesis) Reaction

Cations and anions of two different compounds switch places.

Example of Double Replacement Reaction

AX + BY → AY + BX.

Precipitate

A solid that forms and separates from a solution during a chemical reaction.

Solubility Rule (SNAP)

Memory aid for soluble ions: Sodium, Nitrate, Ammonium, Potassium.

Amphoteric Substance

A substance that can act as either an acid or a base.

Brønsted-Lowry Acid

A proton (H+) donor.

Brønsted-Lowry Base

A proton (H+) acceptor.

Neutralization Reaction

A reaction between an acid and a base producing a salt and water.

Net Ionic Equation for Strong Acid/Base

H+(aq) + OH-(aq) → H2O(l).

Gas-Forming Acid-Base Reaction

Produces gas from a neutralization reaction with carbonates/bicarbonates.

Redox Reaction

Characterized by the transfer of electrons, changing oxidation states.

OIL RIG

Oxidation Is Loss; Reduction Is Gain.

Determine Oxidation Numbers Rule

Assign based on standard rules and track changes in reactions.

Oxidation Half-Reaction

Shows oxidation process: Fe → Fe3+ + 3e-.

Reduction Half-Reaction

Shows reduction process: Cl2 + 2e- → 2Cl-.

Common Mistake: Charge vs Oxidation Number

Oxidation numbers are a bookkeeping method, while charge is a physical property.

Common Mistake: Spectator Ions

Spectator ions that do not change must be removed in net ionic equations.

Common Mistake: Combustion Products

Hydrocarbon combustion should produce H2O, not H2.