the set-up of your lab station.Make
sure you have two burets labeled acid and NaOH.Make sure the burets have a minimum of 40 mL of either acid or base in
them to start with.You should have a
beaker for waste, a wash bottle of distilled water and an Erlenmeyer flask in
which to perform the titration.You will
also need phenolphthalein indicator solution in a dropper bottle.
exact initial volume of acid
buret.Dispense about 10 mL HC2H3O2
into Erlenmeyer flask (the exact amount is not critical – just make sure you
record the exact amount you dispense).Record the exact final volume
of the buret.
approximately 10 mL of distilled water to the Erlenmeyer flask (measure out 10
mL in a graduated cylinder, then pour into the flask) and 2-3 drops of
the exact initial volume of the NaOH
buret.Carefully add NaOH with constant
swirling of the flask until a very pale, persistent pink color is
reached.This is your equivalence point
(endpoint).Record the exact final volume of the buret.
you go past the equivalence point (very dark pink) add HC2H3O2
into the flask until the
color clears (no more pink), then carefully
add NaOH drop by drop until you reach the endpoint (pale, persistent
pink).Record your new final volumes of
HC2H3O2 and NaOH.
may be emptied down the drain.Rinse
flask several times with distilled water.It is not necessary to dry the flask.
steps 2-5 two more times.Add more vinegar
and NaOH as necessary, using the correct funnel.
of standard NaOH solution: ___________
(Vf - Vi)
(Vf - Vi)
and balance the neutralization equation for acetic acid and sodium hydroxide.
the molarity of acetic acid for each trial.
the concentration from each trial, calculate the average molarity of HC2H3O2.
label for vinegar says that the acid has been diluted to 5% by mass, which
translates into roughly 0.830 M.Were your results accurate?Were
they precise?Explain your answers to
both.(Remember the difference?If you don’t remember, you better look it
express accuracy by calculating % difference for EACH trial and the
average concentration of vinegar you found.