Solubility Rules to Know (AP Chemistry)

Solubility Rules to Know

Solubility Rules

Guidelines that predict which compounds will dissolve in water.

Alkali Metal Compounds

All compounds containing alkali metals (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Fr⁺) are soluble in water.

Ammonium Compounds

All compounds containing the ammonium ion (NH₄⁺) are soluble in water.

Nitrates, Acetates, Chlorates

All nitrates (NO₃⁻), acetates (C₂H₃O₂⁻), and chlorates (ClO₃⁻) are soluble.

Halides

Most chlorides, bromides, and iodides are soluble, with exceptions for Ag⁺, Pb²⁺, and Hg₂²⁺.

Sulfates

Most sulfate compounds (SO₄²⁻) are soluble, with exceptions for Ba²⁺, Sr²⁺, Pb²⁺, and Ca²⁺.

Hydroxides

Most hydroxides (OH⁻) are insoluble, with exceptions for alkali metals and Ba(OH)₂.

Carbonates, Phosphates, Sulfides

Most carbonates (CO₃²⁻), phosphates (PO₄³⁻), and sulfides (S²⁻) are insoluble, except when paired with alkali metals or NH₄⁺.

Polyatomic Ions with Alkali Metals

Compounds containing polyatomic ions paired with alkali metals or ammonium are generally soluble.

Chlorides

Compounds that typically dissolve in water barring exceptions for Ag⁺, Pb²⁺, and Hg₂²⁺.

Sulfates

Compounds that typically dissolve in water with notable exceptions like BaSO₄ and PbSO₄.

Hydroxides

Most hydroxides are insoluble, except for those formed with alkali metals and barium.

Carbonates

Most carbonates are insoluble, except those with alkali metals or NH₄⁺.

Aqueous Solution

Solutions in which the solvent is water.

Precipitates

Solid formed in a solution during a chemical reaction.

Alkali Metals

Group of elements that are highly reactive and form soluble salts.

Ammonium Ion

A positively charged polyatomic ion (NH₄⁺) that enhances solubility.

Dissolution

The process by which substances dissolve in solvents.

Ionization Energy

The energy required to remove an electron from an atom.

Solubility

The ability of a substance to dissolve in a solvent.

Reactivity

The tendency of a substance to undergo chemical reactions.

Food Preservatives

Substances used to preserve food by preventing spoilage.

Fertilizers

Chemical substances used to enhance soil fertility.

Explosives

Substances that undergo rapid decomposition producing gas and heat.

Polyatomic Ions

Ions made up of two or more atoms.

Acidic Ions

Ions that can donate protons or accept electrons.

Soluble Compounds

Compounds that dissolve well in water.

Insoluble Compounds

Compounds that do not dissolve in water.

Solubility Product

The constant for a saturated solution of a sparingly soluble ionic compound.

Ionic Bonds

Chemical bonds formed between charged ions.

Salts

Ionic compounds formed from the neutralization reaction of an acid and a base.

Chemical Reactions

Processes in which substances interact to form new substances.

Aqueous Reaction

Reactions that occur in water-based solutions.

Applications in Medicine

Uses of compounds in medical treatments or imaging.