Ch. 4 Compounds and Stoichiometry

____ are substances composed of two or more elements in a fixed proportion

compounds

____ ____ is the mass (in amu) of the constituents in a compound as indicated by the molecular formula

molecular weight

____ _____ is the mass of one mole (Avogadro’s number or 6.022 × 10²³ particles) of a compound; usually measured in grams per mole

molar mass

____ _____ _____ is a measure of the mass of a substance that can donate one equivalent of the species of interest

gram equivalent weight

_____ is the ratio of equivalents per liter; it is related to molarity by multiplying the molarity buy the number of equivalents present per mole of compound

normality

_____ are moles of the species of interest; equivalents are most often seen in acid-base chemistry (hydrogen ions or hydroxide ions) and oxidation-reduction reactions (moles of electrons or other ions)

equivalents

the law of constant composition states that

any pure sample of a compound will contain the same elements in the same mass ratio

the empirical formula is the

smallest whole-number ratio of the elements in a compound

the molecular formula is either

the same as or a multiple of the empirical formula; it gives the exact number of atoms of each element in a compound

to calculate percent composition by mass

determine the mass of the individual element and divide by the molar mass of the compound

______ reactions occur when two or more reactants combine to form one product

combination

_______ reactions occur when one reactant is chemically broken down into two or more products

decomposition

_____ reactions occur when a fuel and an oxidant (typically oxygen) react, forming the products H2O and Co2 (if the fuels is a hydrocarbon)

combustion

______ reactions occur when one or more atoms or ions of one compound are replaced with one or more atoms or ions of another compound

displacement

single-displacement reactions occur when

an ion of one compound is replaced with another element

double-displacement reactions occur when

elements from two different compounds trade places with each other to form 2 new compounds

______ reactions are those in which an acid reacts with a base to form a salt (and, usually, water)

neutralization

balanced equation are determined using these steps in order

1. balancing the least common atoms

2. balancing the more common atoms (H, O)

3. balancing charge

balanced equations can be used to determine the ___ ___, which is the reactant that will be consumed first in a chemical reaction

limiting reagent

reactants other than the limiting reagent are termed

excess reagents

_____ _____ is the amount of product generated if all of the limiting reactant is consumed with no side reactions

theoretical yield

actual yield is typically ____ than theoretical yield

lower

percent yield is calculated by

dividing the actual yield by the theoretical yield and converting to a percentage

roman numerals are used for nonrepresentative elements to denote

ionic charge

-ous ending can also be used to indicate ____ charge, while -ic endings indicate ____ charge

lesser, greater

all monoatomic anions end in

-ide

Oxyanions are given a suffix indicating how oxidized the central atom is. Those that contain a lesser amount of oxygen are given the suffix _____, and those with a greater amount are given the suffix _____

-ite, -ate

oxyanion series with more than two members are given an additional level of nomenclature. The species with the fewest oxygens is given the prefix _____, and the species with the most oxygen is given the prefix _____

hypo-, per-

polyatomic ions containing hydrogen denote the number of hydrogens using hydrogen or ___ to denote one, or ____ to denote two

bi-, dihydrogen

____ charges are predictable by group number and type of element (metal or nonmetal) for representative elements, but are generally unpredictable for nonrepresentative elements

ionic

_____ contain equivalents of ions from molecules that dissociate in solution. The strength of an electrolyte depends on its degree of dissociation or ______

electrolytes, solvation