Chem& 110 Experiment F – Vitamin C in Beverages Lab Tutorial
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Chem& 110 Experiment F – Vitamin C in Beverages Lab Tutorial

March 8, 2020

In this lab tutorial for the Vitamin C
Titration lab, we’ll start by preparing the samples. Use a piece of cheesecloth
to strain any solids from your sample, or use an Erlenmeyer flask and a stopper
to remove any carbonation from your sample. Set these aside. Using a pipette
and a pipette pump, transfer 10 milliliters of your first sample into an
Erlenmeyer flask, followed by: 25 milliliters of deionized water, 2
milliliters of 6 molar acetic acid, and four mililiters of one percent starch.
Give it a small stir and set that aside. Using a buret holder, assemble your
buret so that it is stable and level. Transfer some iodine solution into the
opening of the buret and you can use a funnel to prevent any spills. It may be
useful to fill the buret past the zero marking as you will need to release some
of the iodine to remove any trapped air. Record your starting volume. From here,
begin your titration. Add the iodine solution drop-wise to begin as you don’t
want to over titrate your sample. Be sure to continuously stir in
between the drops. After some time, a faint blue color should
appear. This can get tricky with darker colored samples, but if you notice a
dark blue color appear, you’ve over titrated and you cannot consider this a
valid trial. Record the volume that you stopped at. Repeat this with the second sample. Here, we’ve given you a comparison
between a correctly titrated and an over titrated sample. With that, you’ve
finish the lab and good luck. Thank you for watching!

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