Chem 101L - Exploration of Solutions

What is miscibility?

The ability of two liquids to mix to form a homogeneous solution.

What does it mean if two liquids are immiscible?

They do not mix; instead, they separate into distinct layers.

What is the rule of miscibility?

"Like dissolves like." Substances with similar IMFs are miscible.

Why are water and oil immiscible?

Water is polar (H-bonding), oil is nonpolar (dispersion forces), so they prefer self-interactions.

Which IMF types influence miscibility?

Hydrogen bonding, dipole-dipole, ion-dipole, and London dispersion forces.

Why is NaCl a solid at room temperature?

Strong electrostatic attractions between Na⁺ and Cl⁻ in the ionic lattice.

What is an ion-dipole interaction?

Attraction between an ion and a polar molecule's dipole (e.g., water with Na⁺/Cl⁻).

Why is water good at dissolving ionic compounds?

It forms strong ion-dipole interactions, stabilizing separated ions (hydration spheres).

Will nonpolar solvents dissolve ionic solids?

No — they cannot form ion-dipole interactions strong enough to break the ionic lattice.

Which cations always produce soluble compounds?

Group 1 ions and NH₄⁺.

Which anions always produce soluble compounds?

NO₃⁻, ClO₄⁻, CH₃COO⁻ (acetate).

Chlorides, bromides, iodides are soluble except with which cations?

Ag⁺, Cu⁺, Hg₂²⁺, Pb²⁺.

Sulfates (SO₄²⁻) are soluble except with which cations?

Ba²⁺, Pb²⁺, Hg₂²⁺, Ca²⁺, Sr²⁺.

Which anions generally have limited solubility?

F⁻, O²⁻, CO₃²⁻, PO₄³⁻, AsO₄³⁻, CrO₄²⁻, C₂O₄²⁻, except with Group 1 and NH₄⁺.

What is true about hydroxides and sulfides?

Insoluble except with Group 1, NH₄⁺, Ca²⁺, Sr²⁺, Ba²⁺.

What is a precipitation reaction?

A reaction where mixing two aqueous ionic solutions forms an insoluble solid (precipitate).

When does a precipitate form?

When a product of the reaction is insoluble according to solubility rules.

What is an overall ionic equation?

A chemical equation showing all ions present in solution.

What are spectator ions?

Ions that appear unchanged on both sides of the ionic equation.

What is a net ionic equation?

An equation where spectator ions are removed, showing only species that undergo a change.

Why must you identify solubility before writing a net ionic equation?

To determine which product becomes a solid and should be included in the net ionic equation.

What IMF is needed for dissolving ionic compounds?

Ion-dipole interactions.

What IMF dominates nonpolar solvents like hexane?

London dispersion forces.

Why do polar and nonpolar liquids often separate?

Their IMFs are incompatible — they prefer to interact with similar types of molecules.

Define "solute."

The substance that is dissolved.

Define "solvent."

The substance that does the dissolving.

Define "aqueous solution."

A solution where water is the solvent.