Proper use of a buret for a titration procedure
Summary
TLDRThis video offers a detailed guide on using a buret for titration experiments. It emphasizes the importance of cleaning the buret, filling it with titrant solution, and performing the titration with precision. The video demonstrates how to accurately read the meniscus, use a reading card for better visibility, and estimate the endpoint by observing color changes with phenolphthalein as an indicator. It also advises on conducting multiple trials for consistency and accuracy in recording data.
Takeaways
- 🔍 Always ensure your buret is clean before starting a titration experiment.
- 💧 Rinse the buret with deionized water to avoid contamination.
- 🧼 Use detergent and water with a long-handled brush to clean the buret if water beads are observed.
- 🏺 Pour deionized water into the buret using a beaker, not directly from the faucet.
- 📌 Securely attach the buret to a stand with a clamp to prevent movement during titration.
- 🧪 Use sodium hydroxide as a titrant and phenolphthalein as an indicator for titrating acetic acid.
- 💧 Rinelyou the buret with the titrant solution multiple times before starting the titration.
- 🌡️ Check the initial liquid level in the buret and ensure it's below the zero mark.
- 📏 Use a reading card to accurately estimate the meniscus position on the buret scale.
- 📝 Record the initial and final readings of the buret to the nearest hundredth of a milliliter.
- 🔬 Practice estimating the meniscus position to improve accuracy and consistency in titration results.
Q & A
What is the first step to prepare a buret for titration?
-The first step is to ensure that the buret is clean and rinse the inside with deionized water.
How do you know if the buret is clean after rinsing?
-If the water sheets down the side of the glass evenly without holding droplets of water, then the buret is considered clean.
What should you do if the buret holds droplets of water after rinsing?
-If the buret holds droplets of water, it should be cleaned with detergent and water using long-handled brushes.
How should you rinse the buret after using detergent?
-Rinse the buret thoroughly first with tap water and then with deionized water.
What is the recommended method to fill the buret with solution?
-Use a beaker to pour the solution into the top of the buret instead of holding the opening under the faucet.
Why is it important to secure the buret with a clamp?
-Securing the buret with a clamp ensures it is firmly in place and prevents it from moving during the titration process.
What is the purpose of rinsing the buret with the titrant solution before titration?
-Rinsing the buret with the titrant solution ensures that any residual water does not dilute the titrant, affecting the accuracy of the titration.
Why is it necessary to coax any bubbles out of the tip of the buret?
-Bubbles in the tip can cause an inaccurate reading and affect the delivery of the titrant, thus it's important to remove them for precise titration.
What is the purpose of using a reading card when measuring the volume in the buret?
-A reading card helps to clearly see the meniscus against the white background, providing a more accurate reading of the volume.
How should you position your eyes when reading the meniscus?
-Your eyes should be positioned in the same plane as the tangent drawn to the bottom of the meniscus for an accurate reading.
What is the significance of recording the initial reading in each titration?
-Recording the initial reading is crucial for determining the volume of titrant used and calculating the concentration of the analyte.
How can you estimate the endpoint of the titration?
-You can estimate the endpoint by conducting a preliminary trial to find the approximate endpoint, then conducting subsequent trials more carefully from a point close to the end.
What is the Troop endpoint and how is it determined?
-The Troop endpoint is the first faint color that remains after 15 seconds of stirring, indicating the end of the titration.
Outlines
🧪 Proper Buret Usage for Titration
This paragraph outlines the correct procedure for using a buret in a titration experiment. It emphasizes the importance of cleaning the buret with deionized water and detergent, using a brush to scrub the interior. The buret should be filled with a beaker rather than directly from a faucet, and secured with a clamp. The paragraph details the process of titrating acetic acid with sodium hydroxide using phenolphthalein as an indicator. It advises on how to fill the buret, remove air bubbles, and start the titration. The importance of accurate readings and the use of a reading card for precise meniscus observation is highlighted. The goal is to achieve consistent and accurate data to the nearest hundredth of a milliliter.
🎨 Capturing Color Change in Titration
The second paragraph focuses on the technique for accurately capturing the color change during the endpoint of a titration. It suggests running the first trial quickly to estimate the endpoint and then conducting subsequent trials more carefully. The paragraph provides a method for observing the color change by slowly opening the stopcock and using a wash bottle to rinse the droplet into the reaction flask. It clarifies that adding small amounts of water does not affect the endpoint appearance and defines the Troop endpoint as the first faint color that persists after 15 seconds of stirring. The paragraph concludes with instructions to carefully read and record the ending volume to the nearest hundredth of a milliliter.
Mindmap
Keywords
💡Buret
💡Deionized Water
💡Titration
💡Phenolphthalein
💡Stopcock
💡Meniscus
💡Reading Card
💡Endpoint
💡Titration Flask
💡Waste Beaker
💡Dust Cap
Highlights
Ensure that the buret is clean before starting the titration experiment.
Rinse the buret with deionized water to ensure even flow.
Clean the buret with detergent and water if water droplets hold on the glass.
Use long-handled brushes to clean the inside of the buret.
Rinse the buret thoroughly with tap water followed by deionized water.
Pour deionized water into the buret using a beaker instead of holding it under the faucet.
Securely attach and lock the buret into place with a clamp.
Use sodium hydroxide to titrate acetic acid with phenolphthalein as the color indicator.
Ensure the stopcock is closed before pouring the titrant solution into the buret.
Rinse the buret with the titrant solution multiple times before starting the titration.
Pour the liquid out into a waste beaker to prepare for titration.
Refill the buret for titration and coax any bubbles out of the tip.
Position a beaker to catch waste solution below the buret tip.
Estimate the meniscus position on the graduated scale for accurate readings.
Use a reading card to help determine the meniscus position.
Ensure consistent positioning of the reading card and eyes for accurate readings.
Estimate the meniscus position to the nearest hundredth of a milliliter.
Record the initial reading of each titration for consistency.
Transfer the sample to the titration flask carefully to avoid losing drops.
Run multiple trials with the same sample for consistent results.
Use a technique to capture the color change within a fraction of a drop at the endpoint.
The endpoint is the first faint color that remains after 15 seconds of stirring.
Record the ending volume to the nearest hundredth of a milliliter in the laboratory notebook.
Transcripts
this video will cover the proper use of
a buret look elsewhere for specific
information about the chemistry of your
particular type of titration experiment
before you begin ensure that your buret
is clean rinse the inside with some
deionized water the water should sheep
down the side of the glass evenly if the
glass holds droplets of water as shown
here then clean the buret with detergent
and water use the long handled brushes
that extend the full length of the
Barrette put some detergent and water on
the brush and scrub the inside
rinse the buret thoroughly first with
tap water and then with deionized water
use a beaker to pour into the top of the
buret rather than trying to hold the
opening of the buret under the faucet
attach a buret clamp firmly to the stand
and lock the buret into place
in this demonstration we will be using
sodium hydroxide to titrate a solution
of acetic acid using phenolphthalein as
a color indicator of the endpoint of the
titration
be sure that the stopcock is closed and
then pour the titrant solution slowly
into the open end
rinse the buret with five to ten
milliliter portions
two or three more times
rotate the buret slowly as you pour the
liquid out into a waste beaker
now refill the briaret for the titration
place a beaker for catching waste
solution below the buret tip use several
quick twists of the stopcock valve to
introduce liquid into the bottom of the
bread and coax any bubbles out of the
tip
if necessary bring the liquid level back
near the top you don't have to start
exactly at the zero Mark the meniscus
must however begin somewhere below the
line associated with zero if you've used
a funnel to pour into the buret then
remove it now so it does not drip into
the buret after you've started your
titration that would lead to an error
you may also want to add a dust cap
estimate where the bottom of the
meniscus is on the graduated scale you
may find it helpful to use a reading
card a reading card is merely a colored
rectangle on a white background by
bringing the rectangle up just below the
meniscus colored light is reflected off
the curved surface to give a distinct
outline against the white background if
you use this method be careful about
keeping the rectangle at a consistent
distance from the bottom of the meniscus
each time you read the meniscus may
appear to move as the rectangle moves
equally important is positioning your
eyes so that it is it's in the same
plane as the tangent drawn to the bottom
of the meniscus here the position of the
meniscus is between the zero and the one
milliliter Mark the shorter lines that
do not go all the way around the buret
are associated with intervals of 0.1
milliliter
in this case the meniscus appears to be
between the seventh and the eighth marks
so its position is at least 0.7
milliliters we can estimate the fraction
of the gap between the nearest lines
spanned by the bottom of the meniscus
here it appears to be a little bit less
than halfway perhaps 40 percent of the
interval in that case we estimate this
position of this meniscus at the start
of this titration to be about
0.74 milliliters
this last digit is a guess but with a
little practice you can learn to be very
consistent and obtain reproducible and
accurate data to the nearest hundredth
of a milliliter
that should be your goal in your work
today be sure to record your initial
reading in each of your titrations
we're ready now to transfer the sample
to our titration flask in this
demonstration we are using acetic acid
as a sample
we count the number of drops of
indicator that are added so that our
results will be as consistent as
possible from run to run we place the
titration flask under the buret point so
that the buret is slightly below the rim
of the flask this minimizes the chance
for losing an errant drop
we begin adding titrant if we have a
good idea roughly where the end of the
titration will occur then we can save
some time by running the titrant into
the flask to within a milliliter of two
of the expected endpoint it is common
practice to run multiple trials with
portions of the same sample so it is
good strategy to run one trial very
quickly really to find out where the
approximate endpoint is
the next few trials can be done
carefully from a point very close to the
end
the first trial does not need to be
averaged with the more carefully
obtained data close to the endpoint the
color disperses more gradually
here is a technique for capturing the
color change to within a fraction of a
drop of the end point open the stopcock
very slowly only part way allow a
droplet to grow about half its full size
then use the wash bottle to rinse the
drop down into the reaction flask
adding small amounts of water does not
change the appearance of the end point
The Troop endpoint is in this case the
first faint color that remains after 15
seconds of stirring
finally carefully read the ending volume
and record it to the nearest hundredth
of a milliliter in your laboratory
notebook
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