Ch. 7: Chemical Reactions and Stoichiometry Overview

Physical Change

Alters state or appearance, not composition.

Chemical Change

Alters composition, forming new substances.

Chemical Reaction

Produces new substances through atom rearrangement.

Evidence of Chemical Reaction

Includes color change, gas formation, heat change.

Chemical Equation

Describes reactants and products in a reaction.

Reactants

Substances consumed in a chemical reaction.

Products

Substances formed in a chemical reaction.

Balancing Chemical Equations

Ensures equal atom count in reactants and products.

Coefficients

Numbers used to balance chemical equations.

Combustion Reaction

Reaction with O2, releasing energy.

Combination Reaction

Two or more reactants form a single product.

Decomposition Reaction

Single reactant breaks into multiple products.

Single Replacement Reaction

One element replaces another in a compound.

Double Replacement Reaction

Two compounds exchange elements or ions.

Stoichiometry

Relationship between reactants and products amounts.

Stoichiometric Coefficients

Indicate relative moles in a reaction.

Limiting Reagent

Reactant completely consumed, limiting product formation.

Excess Reagent

Reactant not fully consumed in a reaction.

Theoretical Yield

Predicted amount of product from stoichiometry.

Actual Yield

Amount of product actually produced.

Percent Yield

(Actual Yield/Theoretical Yield) x 100.

Balanced Equation

Same number of each atom on both sides.

Physical States

(s) solid, (l) liquid, (g) gas, (aq) aqueous.

Law of Conservation of Mass

Mass is conserved in chemical reactions.

Heat Absorption

Energy change indicating a chemical reaction.

Formation of Solid

Precipitate forms during a chemical reaction.

Gas Formation

Bubbles or vapor indicate a chemical change.