Cornelia D'Souza Assignment A
Cornelia D’souza
UNIT 2 practical scientific procedures and techniques
A: Undertake titration and colorimetry to determine the concentration of
solutions.
Introduction
I will use titration and colorimetry to determine the concentration of solutions in the
experiment using actual scientific procedures and techniques. I'll also be urged to
calibrate equipment and be aware of the safety elements of specific laboratory
processes and techniques. In this experiment, I will use a variety of titration and
colorimetry tools, including pH metres and burettes, balances and weighing, and the
safe use of volumetric glassware.
Titration
Titration is a technique that uses a known-concentration solution (a common
laboratory method of quantitative chemical analysis) to determine the concentration
of an unknown solution. The concentration of the analyte (known solution) is typically
added from a burette to a known quantity of analyte (unknown solution) until the
reaction is complete. The concentration of the unknown can be determined by
knowing the volume of titrant added. In titration, an indicator is frequently used to
indicate the conclusion of the reaction, also known as the endpoint. Titration is
applied in medical labs in real life. When administering anaesthetic to a patient,
doctors frequently use titration processes. They will learn the proper concentrations
of anaesthetic to utilise in this manner. Titration can also be used to determine the
kind of fatty acid chain length. This is beneficial for persons who have certain dietary
requirements. This method might also be used to determine the amount of salt and
sugar in foods.
Some benefits of using titration is that it is generally cheap, requiring little in the way
of equipment. Ability to accurately measure. It can often be done rapidly. Results are
immediately available.In addition to accurate calibration of equipment and consistent
titration results, there are a few tips and techniques that can help ensure a skilled
and precise determination of the concentration of a solution of sodium hydroxide:
Skills i developed from this experiment
I thoroughly rinsed and dried all equipment before use to avoid contamination and
ensure precise measurements. putting a white surface under the flask during the
titration so you can more clearly see how the indicator changes colour and get an
accurate endpoint reading. To avoid overshooting the endpoint and adding too much
HCl, I added the HCl solution drop by drop slowly in the direction of the endpoint. To
ensure accuracy and precision, I also recorded measurements down to the nearest
hundredth or thousandth of a unit. To get reliable results and determine the average
,Cornelia D'Souza Assignment A
value, the titration was repeated several times. These allowed me to develop my
skills and focus in order to produce precise results.
Preparing a standard solution of Sodium carbonate (Na2CO3)
Calibration: To begin, the balance was calibrated for weights of 10g, 50g, 100, 200,
and 500g. This was done to ensure the balance was accurate for a variety of
masses; to calibrate the balance, a mass was placed on the balance and the
measurements were adjusted to register the exact mass using a calibration screw.
Then I started by calibrating the weighing balance, which I did by turning it on at
least 5 minutes before the calibration, making sure it was level, and then placing a
weighing boat on top of it and pressing 0 to verify that all of my measurements were
precise. The temperature of the weights should be kept at the same level as the
temperature at which the calibration will be performed. Particularly for small and
precise weighing equipment, the weighing device should be placed horizontally.
Finally, pre-test it by placing weights close to the instrument's maximum range to
confirm it functions normally.
Equipments
● Watch glass
● Weighing balance
● Measuring flask
● Funnel
● Wash bottle
● Cork
● Sodium carbonate (Na2CO3)
● Distilled water
Method
First, I took a watch glass, washed it in distilled water, and dried it. Next, I weighed
and recorded the precise amount of clean and dried watch glass. Then I weighed
1.35 g of sodium carbonate accurately on the watch glass and noted the weight. I
gently and carefully removed the sodium carbonate from the watch glass into a clean
and dry measuring flask using a funnel. Then, using a wash bottle, I washed the
weighing boat with distilled water to shift the particles that had stuck to it into the
foam. The volume of distilled water used for this purpose should not exceed 50 ml.
Using a wash bottle, I had to wash the funnels multiple times with distilled water to
get the stuck particles into the measuring flask. Later, while washing the funnel, I
added water in small amounts. (The amount of distilled water used for this should not
exceed 50 ml.) To pass the solution attached to the funnel into the measuring flask, I
gently cleansed the funnel with distilled water using a wash. Turn the measuring
flask until the sodium carbonate has dissolved. I thoroughly filled the measuring flask
with distilled water using a wash bottle, just below the carved mark on it. Then I
poured the last few mL of distilled water into the measuring flask, just touching the
lowered meniscus level. Finally, I had to place the cork over the flask's mouth and
gently shake the flask to uniformize the solution.
, Cornelia D'Souza Assignment A
Risk assessment
● Risk of spill: Sodium carbonate spills can result in trips and falls. Work slowly,
avoid rushing, and clean up spills right away to reduce this risk.
● Glassware risk: If handled improperly, glass objects like measuring flasks and
funnels can break. Handle glassware with care, and when necessary, wear
the proper protective gear, such as gloves, to reduce this risk.
● Chemical burn risk: Skin and eye burns from sodium carbonate are possible.
Wear the proper personal protective equipment, such as gloves, goggles, and
a lab coat, to reduce this risk.
● Risk of inhalation: If sodium carbonate is inhaled in large amounts, it can
irritate the respiratory system and result in coughing, sneezing, and shortness
of breath. Work in a ventilated area to reduce this risk.
Mass of empty boat (g) 0.18
Mass of weighing boat and sodium 1.53
carbonate (g)
Mass of sodium carbonate (g) 1.35
Formula mass of Sodium Carbonate (Na2CO3):
Na = 23 C = 12 O = 16
(23 x 2) + 12 + (16 x 3) = 106
Moles = 1.35g/106
Moles of Na2CO3 = 0.01274 mol
Carrying out the titration to standardise the hydrochloric acid solution (HCl)
Calibration :I had to calibrate the burette before I could use it by cleaning it
thoroughly and filling it with distilled water, removing air bubbles, then recording the
initial reading. I then Dispense the water into a beaker and weigh it. Repeating the
steps at least two more times. Then Calculating the average volume and relative
error. If the error is within the acceptable range, the burette is calibrated and ready to
use. Burettes are commonly used for the volumetric analysis as any small changes
can affect the reliability By calibrating a burette, you can determine the exact volume
of liquid delivered per unit reading and accuracy.
Equipments
● Conical weighing flask with a ground glass stopper
● Analytical balance
● Burette
● Distilled water
● Tissue or lint-free cloth for wiping the flask and burette tip
● Thermometer (if the room temperature was not already known)
● Weighing boats or paper for weighing the flask
