Vocab

Atomic Mass

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

Atomic mass unit

a mass exactly to 1/12 the mass of one carbon-12 atom

Average atomic mass

average value

Mole (mol)

the amount of a substance that contains exactly 6.02 × 10²³

Avogadro’s number

N_A=6.02 × 10²³

Molar mass

the mass of 1 mole of units of a substance

Molecular mass

(molecular weight) the mass of one molecules

Percent composition by mass

=((n*molar mass of element)/molar mass of compound) * 100

Chemical reactions

a process in which a substance is chnaged into one or more new substances

Chemical equation

uses chemical symbols to show what happens during chemical reaction

reactants

starting materials in a chemical equation

Products

substance formed as aresults of a chemical reaction

Stoichiometry

the quantative study of reactants and products in a chemical reaction

Mole method

an approach for determining the amount of product formed in a reaction

Stoichiometric amounts

the exact molar amounts of reactants and products that appear in the balanced chemical equation

limiting reactants

the reactant used up first in a reaction

Excess reactants

the reactants present in quantities greater than necessary to react with the quantity of the limiting reagent

Theoretical yield

the amount of product that would results if all the limiting reactant reacted

Actual yield

the amount of product actually obtained from a reaction (ALWAYS LESS THAN THE THEORETICAL YIELD)

Percent yield

the proportion of the actual yield to the theoretical yield

Atom economy

a measure of the overall efficiency of converting reactants into useful products