Chemistry Ch 3-4

Abeka Chemistry:Precision and Design,Third Edition

Stoichiometry

The measurement of the elements in chemical reactions.

Chemical formulas

Symbolic representations that specify the elements present in a compound.

Molecular compounds

Compounds composed of molecules, which are groups of two or more atoms.

Ionic compounds

Compounds composed of a vast array of ions, which are electrically charged particles.

Molecular formula

A formula that indicates how many of each type of atom are present in a compound.

Empirical formula

A formula that shows only the simplest ratio of atoms in a compound.

Formula unit

The simplest ratio of atoms in an ionic compound; the smallest division of an ionic compound.

Simple cations

Cations formed by removing one or more electrons from an atom.

Simple anions

Anions formed by adding one or more electrons to an atom.

Polyatomic ions

Ions that consist of several atoms acting as a single ion.

Molecular mass

The sum of the atomic masses of all the atoms in the formula of a compound.

Avogadro’s number

The number 6.022×10²³, representing the number of particles in one mole of a substance.

Mole

The amount of a substance containing the same number of particles as exactly 12g of carbon-12.

Molar mass

The mass of one mole of a substance, typically expressed in grams per mole.

Percent composition

The composition of a compound expressed in percentages by mass.

Chemical equation

A symbolic representation of a chemical reaction.

Reactants

The substances present on the left side of a chemical equation.

Products

The substances present on the right side of a chemical equation.

Law of conservation of mass

The principle stating that the sum of the masses of the products is always equal to the sum of the masses of the reactants.

Limiting reactant

The reactant that determines how much product can be formed in a chemical reaction.

Mole ratio

A conversion factor that compares the amounts of any two substances involved in a chemical reaction.