Chapter 4 – Stoichiometry of Chemical Reactions (Sections 4.1 & 4.2)

Vocabulary flashcards summarizing essential terms from the lecture on writing, balancing, and classifying chemical reactions.

Chemical Equation

A symbolic representation of a chemical reaction showing formulas of reactants and products, their physical states, and relative quantities.

Balanced Chemical Equation

An equation in which equal numbers of each type of atom appear on both the reactant and product sides.

Reactants

Substances that undergo change in a chemical reaction; written to the left of the arrow in an equation.

Products

Substances produced by a chemical reaction; written to the right of the arrow in an equation.

Coefficient

Whole number placed in front of a chemical formula to indicate the relative number of molecules or moles; omitted when the value is 1.

Balancing by Inspection

Method of balancing an equation by adjusting coefficients until atom counts are equal on both sides.

Mole Ratio

The proportional relationship between coefficients in a balanced equation, expressing relative amounts of reactants and products.

(g), (l), (s), (aq)

Parenthetical symbols indicating a substance’s physical state: gas, liquid, solid, or aqueous (dissolved in water).

Δ (delta) over the arrow

Notation used to show that heat is supplied to drive a reaction.

Molecular Equation

Chemical equation that shows compounds as complete, neutral formulas without detailing their ionic character in solution.

Complete Ionic Equation

Equation in which all strong electrolytes are written as separate ions to show the actual species present in aqueous solution.

Spectator Ion

Ion that appears unchanged on both sides of a complete ionic equation and does not participate in the net reaction.

Net Ionic Equation

Equation that shows only the chemical species that actually change during the reaction, excluding spectator ions.

Precipitation Reaction

Reaction in which dissolved substances form one or more solid products (precipitates); also called double displacement or metathesis reaction.

Solubility

Maximum concentration of a substance that can dissolve in a solvent at specified conditions; high solubility ⇒ soluble, low solubility ⇒ insoluble.

Solubility Rules

Empirical guidelines predicting whether common ionic compounds are soluble or insoluble in water.

Insoluble Compound

Substance with very low solubility that readily precipitates from solution when its concentration exceeds its solubility limit.

Double Displacement (Metathesis) Reaction

Reaction type where two ionic compounds exchange ions to form two new compounds, often producing a precipitate or water.

Stoichiometry

Area of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction.

Aqueous Solution

Homogeneous mixture in which a substance (solute) is dissolved in water (solvent), designated with (aq).

Fractional Coefficient (Intermediate)

Non-integer coefficient temporarily used while balancing an equation, later cleared by multiplying all coefficients by a whole number.

Spectator-free Reaction Example

Ag⁺(aq) + Cl⁻(aq) → AgCl(s); illustrates a net ionic equation after spectator ions are removed.