Compounds and Stoichiometry Flashcards
what is avogadro’s number
6.022 x 1023 mol ^-1
what are equivalents
how many moles of the thing we are interested in will one mole of a given compound produce
gram equivalent weight formula
molar mass/n
where n is the number of particles of interest produced or consumed per molecule of the compound in the reaction
what is the equivalent weight of a compound
the mass that provides one mole of the particle of interest
equivalent formula
mass of compound (g) / gram equivalent weight (g)
what is normality
a measure of concentration given in the units:
equivalents / L
the conversion from normality to molarity formula
molarity = normality / n
where n is the number of protons, hydroxide ions, or ions produced/consumed by the solute
a real benefit of working with normality and equivalents
it allows a direct comparison of the quantities of the entity we are most interested in
what is the law of constant composition
states that any pure sample of a given compound will contain the same elements in an identical mass ratio
what is the empirical formula
the simplest whole-number ratio of the elements in the compound
what is the molecular formula
the exact number of atoms of each element in the compound
percent composition formula
mass of element in formula / molar mass * 100%
what is a combination reaction
when two or more reactants form just one product
what is a decomposition reaction
when a single reactant breaks down into two or more products
usually the result of heating, high-frequency radiation, or electrolysis
what is a combustion reaction
a special type of reactions that requires a fuel (usually a hydrocarbon) and an oxidant
in most common form, reactants will produce water and carbon dioxide
what is a single-displacement reaction
when an atom or ion in a compound is replaced by an atom or ion of another element (usually classified as an oxidation-reduction)
what is a double displacement reaction
elements from two different compound swap places with each other to form two new compounds
the rxn occurs when one of the products is removed from the solution as a precipitate or gas OR when two of the original species combine to form a weak electrolyte
(aka metathesis rxn)
what are neutralization reactions
a specific type of double-displacement reaction in which an acid reacts with a base to produce a salt (and usually water)
what is a limiting reagent
the reactant that will be used up or consumed first
essentially, it limits the amount of product can be produced
what are the two principles that you want to keep in mind for problems involving the determination of the limiting reagent
- all comparisons must be done in units of moles, not gram-to-gram comparisons
- it is not the absolute mole quantities that determine which reactant is the limiting reagent, but rather the rate at which the reactants are consumed (stoichiometric ratios of reactants) combined with the absolute mole quantities determines which reactant is the limiting reagent
what is the yield of a reaction
can refer to either the amount of product predicted or actually obtained
what is the theoretical yield
the maximum amount of product that van be generated as predicted from the balanced equation
what is the actual yield
the amount of product one actually obtains during the reaction
percent yield formula
actual yield / theoretical yield * 100%
