Compounds and Stoichiometry

Question 1

what is avogadro’s number

Answer 1

6.022 x 1023 mol ^-1

Question 2

what are equivalents

Answer 2

how many moles of the thing we are interested in will one mole of a given compound produce

Question 3

gram equivalent weight formula

Answer 3

molar mass/n
where n is the number of particles of interest produced or consumed per molecule of the compound in the reaction

Question 4

what is the equivalent weight of a compound

Answer 4

the mass that provides one mole of the particle of interest

Question 5

equivalent formula

Answer 5

mass of compound (g) / gram equivalent weight (g)

Question 6

what is normality

Answer 6

a measure of concentration given in the units:
equivalents / L

Question 7

the conversion from normality to molarity formula

Answer 7

molarity = normality / n
where n is the number of protons, hydroxide ions, or ions produced/consumed by the solute

Question 8

a real benefit of working with normality and equivalents

Answer 8

it allows a direct comparison of the quantities of the entity we are most interested in

Question 9

what is the law of constant composition

Answer 9

states that any pure sample of a given compound will contain the same elements in an identical mass ratio

Question 10

what is the empirical formula

Answer 10

the simplest whole-number ratio of the elements in the compound

Question 11

what is the molecular formula

Answer 11

the exact number of atoms of each element in the compound

Question 12

percent composition formula

Answer 12

mass of element in formula / molar mass * 100%

Question 13

what is a combination reaction

Answer 13

when two or more reactants form just one product

Question 14

what is a decomposition reaction

Answer 14

when a single reactant breaks down into two or more products
usually the result of heating, high-frequency radiation, or electrolysis

Question 15

what is a combustion reaction

Answer 15

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

Question 16

what is a single-displacement reaction

Answer 16

when an atom or ion in a compound is replaced by an atom or ion of another element (usually classified as an oxidation-reduction)

Question 17

what is a double displacement reaction

Answer 17

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)

Question 18

what are neutralization reactions

Answer 18

a specific type of double-displacement reaction in which an acid reacts with a base to produce a salt (and usually water)

Question 19

what is a limiting reagent

Answer 19

the reactant that will be used up or consumed first
essentially, it limits the amount of product can be produced

Question 20

what are the two principles that you want to keep in mind for problems involving the determination of the limiting reagent

Answer 20

1. all comparisons must be done in units of moles, not gram-to-gram comparisons
2. 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

Question 21

what is the yield of a reaction

Answer 21

can refer to either the amount of product predicted or actually obtained

Question 22

what is the theoretical yield

Answer 22

the maximum amount of product that van be generated as predicted from the balanced equation

Question 23

what is the actual yield

Answer 23

the amount of product one actually obtains during the reaction

Question 24

percent yield formula

Answer 24

actual yield / theoretical yield * 100%

Question 25

what are electrolytes

Answer 25

solutes that enable solutions to carry currents