stoich Flashcards
percentage yield
what you produce experimentally, compared to what was theoretically possible
theoretical yield
quantity of product expected to be produced if everything goes perfectly
experimental yield
the quantity of product actually produced
percentage yield equation
experimental/theoretical x 100%
limiting reagent
reactant that limits the quantity of product formed
excess reagent
reactant that still has some quantity remaining once the reaction is done
stoichiometry
the study of relationship between quantities of reactants and products involved in a chemical reaction
what is the relationship in stoichiometry?
molar coefficients of the balanced chemical reaction
mole ratio
“stoichiometric ratio”; given by the coefficients of the BCR
Gravimetric stoich solves for…
a chemical’s mass
general idea of gravimetric stoich
- given mass –> moles
- connect given moles –> required moles
- required moles –> mass
pH curve
graphical representation of the progression of an acid-base titration
how is the pH curve obtained?
performing a titration of one reactant into a sample flask of the other reactant
if the tip of the burette is perpendicular, then..
the tip is closed
if the tip of the burette is parallel, then..
the tip is open
what is the burette estimated to compared to what it’s calibrated to
estimated to a hundredth, calibrated to a tenth of a mL
parts of pH curve when a strong acid is titrated into a strong base
- OH- only in sample
- H3O+ being added
- small quantity of H3O+ being added results in dramatic decrease in pH
- excess H3O+ (OH- is neutralized)
endpoint
(y-coordinate) pH @ which the acid and base neutralize
appropriate indicators in a titration
an indicator with a pH=7 will be a midpoint colour
- bromothymol blue
- phenol red
equivalence point
(x-coordinate) volume of titrant required to perfectly neutralize sample
parts of a pH curve when strong base is titrated into a strong acid
- excess H30+
- equivalence point ( pH increases dramatically as more OH- is added)
- excess OH-
solution stoich equation
c=n/v
what does solution stoich solve for
volume and concentration
what does gas stoich solve for
volume
gas stoich equation
PV=nRT
R constant
8.314
STP
101.325 kPa
0C
SATP
100kPa
25C
titration
used to determine the concentration of a solution when the concentration of one solution is known and the volume of both solutions is known
how can the concentration of an unknown solution be determined (reference to titration)
-pH curve
-multi-trial titration
multi-trial titration
titrant is added to the sample, but the titration is stopped when the endpoint is reached
how to determine the volume of titrant required to enutralize the sample
Vf - Vi
why are multiple trials done in multi-tiral titrations
- improve precision/reliability of results
- eliminate outlying trials
how are trials selected from multi-trial titrations
3 trials within +/- 0.20 mL
titration data table title
titration os xxxx mL (xxx mol/L) sample with (xxx mol/L) titrant
