Chapter 3: Mass Relationships in Chemical Reactions Flashcards
atomic mass
AKA atomic weight
the mass of the atom in atomic mass units (amu)
atomic mass unit
a mass exactly equal to one-twelfth the mass of one carbon-12 atom
mole (mol)
the amount of a substance that contains as many elementary entities (atoms, molecules, or other particles) as there are atoms in exactly 12g (or 0.012kg) of the carbon-12 isotope
molar mass (M)
the mass (in grams or kilograms) of 1 mole of units (such as atoms or molecules) of a substance
molecular mass
AKA molecular weight
the sum of the atomic masses (in amu) in the molecule
percent composition by mass
percent by mass of each element in a compound
chemical reaction
a process in which a substance (or substances) is changed into one or more new substances
chemical equation
uses chemical symbols to show what happens during a chemical reaction
reactants
the starting materials in a chemical reaction
product
the substance formed as a result of a chemical reaction
stoichiometry
the quantitative study of reactants and products in a chemical reaction
mole method
the stoichiometric coefficients in a chemical equation can be interpreted as the number of moles of each substance
stoichiometric amounts
in the proportions indicated by the balanced equation
limiting reagent
the reactant used up first in a reaction
excess reagents
reactants present in quantities greater than necessary to react with the quantity of the limiting reagent
Avogadro’s number
the actual number of atoms in 12g of carbon-12 determined experimentally
Four Interpretations of a Chemical Equation
