Chapter 3 - Mass Relationships in Chemical Reactions | Definition

Atomic mass

the mass of an atom in atomic mass units (amu)

average atomic mass

the weighted average of all of the naturally occurring isotopes of the element

Mole (mol)

unit to count numbers of particles and the amount of a substance that contains as many elementary entities as there are atoms in exactly 12g of C12

Avogadro’s number (N_A)

6.02×1023

molecule

an aggregate of two or more atoms in a definite arrangement held together by chemical forces.

Molecular mass (or molecular weight)

the sum of the atomic masses (in amu) in a molecule.

Percent composition of an element in a compound

chemical reaction

A process in which one or more substances is changed into one or more new substances

chemical equation

uses chemical symbols to show what happens during a chemical reaction

3 ways of representing the reaction of H2 with O2 to form H2O

Theoretical Yield

the amount of product that would result if all the limiting reagent reacted.

Actual Yield

the amount of product actually obtained from a reaction.

Formula of Reaction Yield