Acids, Bases, and Salts – AP Chemistry Fundamentals (Fall 2024)

Vocabulary flashcards covering key terms, chemicals, and processes related to acids, bases, salts, and their industrial applications as presented in the lecture notes.

Acid

A substance that releases hydrogen ions (H⁺) in water; acts as a proton donor and turns blue litmus red.

Base

A substance that produces hydroxide ions (OH⁻) in water or accepts H⁺; feels slippery, tastes bitter, and neutralizes acids.

pH Scale

A logarithmic 0–14 scale indicating acidity or basicity of an aqueous solution (7 = neutral,

Strong Acid

Acid with pH < 2 that completely dissociates in water (e.g., HCl, H₂SO₄).

Strong Base

Base with pH > 12 that completely dissociates in water (e.g., NaOH, Ca(OH)₂).

Weak Acid

Acid that only partially dissociates in water, giving a pH closer to neutral (e.g., CH₃COOH).

Weak Base

Base that only partially dissociates or accepts protons, yielding moderate alkalinity.

Salt

An ionic compound formed from the cation of a base and anion of an acid during neutralization.

Neutralization Reaction

Acid + Base → Salt + Water; fundamental for salt formation and equilibrium.

Sodium Chloride (NaCl)

Common salt; white crystalline solid vital to food, physiology, and chemical industries.

Halite

Naturally occurring rock-salt mineral form of NaCl mined from underground deposits.

Seawater

Primary natural source of NaCl (~2.7 % salt) harvested by solar evaporation.

Rock Salt Mining

Extraction of solid halite from underground deposits using techniques similar to coal mining.

Brine Purification

Process of injecting water into salt beds, pumping saturated brine, removing impurities, and evaporating to pure salt.

Chlor-Alkali Process

Industrial electrolysis of brine producing NaOH, Cl₂, and H₂ simultaneously.

Electrolysis

Chemical decomposition by electric current; in brine, yields NaOH at cathode and Cl₂ at anode.

Sodium Hydroxide (NaOH)

Caustic soda; strong base used in soap, paper, textiles, and aluminum manufacture.

Chlorine Gas (Cl₂)

Green-yellow gas from brine electrolysis; used for disinfection, PVC, and pesticides.

Hydrogen Gas (H₂)

By-product of chlor-alkali electrolysis; fuel and reagent in ammonia synthesis and reduction processes.

Bleaching Powder (CaOCl₂)

Calcium oxychloride made by passing Cl₂ over slaked lime; used as disinfectant and bleaching agent.

Baking Soda (NaHCO₃)

Sodium bicarbonate; mild basic salt that liberates CO₂ when heated or acidified, used in baking and antacids.

Washing Soda (Na₂CO₃·10H₂O)

Sodium carbonate decahydrate; water-softening, cleaning, and industrial agent obtained from heating NaHCO₃.

Plaster of Paris (CaSO₄·½H₂O)

Calcium sulfate hemihydrate produced by heating gypsum; hardens with water, used in casts and décor.

Water of Crystallization

Fixed water molecules incorporated into a crystal lattice, essential for stability and characteristic form.

Efflorescence

Loss of water of crystallization when a hydrated crystal (e.g., washing soda) is exposed to air.

Crystalline Structure

Highly ordered, repeating atomic or ionic arrangement giving solids definite shapes and sharp edges.

High Melting Point (of salts)

Property resulting from strong ionic bonds holding lattice ions tightly together.

Logarithmic Scale

Scale based on powers of ten; each pH unit represents a ten-fold change in H⁺ concentration.

Proton Donor

Alternate definition of an acid in Brønsted-Lowry theory.

Proton Acceptor

Alternate definition of a base in Brønsted-Lowry theory.

Ionic Compound

Substance composed of cations and anions held together by electrostatic (ionic) bonds.

Anhydrous Compound

A substance lacking water of crystallization, often produced by heating a hydrated crystal (e.g., CuSO₄ from CuSO₄·5H₂O).