Volumetric Flask: What Is It, What Is It For, Calibration

In science, it is oftenthey conduct experiments to investigate ideas. To perform these research, scientists use various tools of experimentation.

The basic research equipment includes tools that can be used to measure lengths, mass and volume. One of the most basic equipment for volume measurement is the volumetric flask.

📋 Here you can find ✍

📌 What is a volumetric flask?

A volumetric flask (measuring flask or volumetric flask) is a laboratory apparatus, a type of laboratory flask, calibrated to contain a precise volume at a certain temperature. Volumetric flasks are used for precise dilutions and for the preparation of standard solutions.

🔹 Volumetric flask use

The volumetric flask is used for accurate measurement of volumes of liquid materials for laboratory experiments. They are more accurate than graduated cylinders and beakers, which are other pieces of equipment used to measure liquids. The volumetric flask is important when accuracy is a factor in the outcome of the experiment.

🍀 Volumetric flask function

A volumetric flask is a glass material used in laboratories to measure the volume in the preparation of solutions and contains a precise amount of liquid material to room temperature. These vials are calibrated using global standards and they come in sizes up to 10,000 milliliters.

Volumetric flasks have long necks with a filling line on the neck for accurate measurement.
The lower area is shaped like a light bulb with a flat bottom to sit on a table or burner.

These jars are considered the most accurate way to measure liquids in comparison with beakers or cylinders. The Kohlrausch volumetric flask is designed for accurate measurements of solids to be dissolved in volumetric solutions.

🌳 How is a volumetric jar used?

To prepare a solution in a volumetric flask, you must follow the following indications:

Measure and add the solute for the solution.Add enough solvent to dissolve the solute.Continue adding solvent until it approaches the marked line on the volumetric flask.Fill the volumetric flask with a pipette or a dropper, using the meniscus of the solution and the flask line to determine the end point.Seal the volumetric flask and invert it to mix the solution well.

❤ Volumetric Flask calibration

Calibration is performed measuring the mass of water contained or supplied by the glass material. The density of water at a given temperature is used to convert the mass in volume.

The pipettes and burettes are calibrated to deliver specific volumes, while the volumetric flasks are calibrated to contain the base.

📌 How is a volumetric flask calibrated?

General Calibration Procedure

As indicated previously, the calibration of volumetric glassware is performed by measuring the body of water contained in the device or supplied through the equal.

This mass data is converted in volume data using the tabulated density of water at temperature calibration. (In a very precise work, the thermometer is also calibrated already that an incorrect temperature reading will lead to the use of a density incorrect for water. This, in turn, will give a volume calibration inaccurate.)

Finally, these data from volume are corrected to the standard temperature of 20 °C. This can be achieved using (2) to describe the coefficient of expansion of the thermal volume of the
water.

In this experiment, the volumetric flask will use gravimetrically determined water. The measured mass of the calibration water is standardized at 20 °C.

Procedure

Record the temperature of laboratory in three or four significant figures. For this experiment use distilled water contained in one of the carboys - not directly from the distilled water tap.

Clean and dry (in an oven at 105 °C for a few minutes, followed by cooling to room temperature) a glass jar and its lid. Use detergent if necessary followed by water from the tap and then rinse with distilled water (also from your own tap).

Use a 105°C oven for a few minutes to dry and cool to room temperature. Do not handle clean glassware with bare hands.

Volumetric Flasks

Calibrate a volumetric flask of 10 mL weighing it empty (and dry) and filling it up to the mark with distilled water.

Fill the flask and empty it three times to make three repeated measurements of it. It is not necessary to dry the flask in the oven between these measurements.

Result

Report your experimental results to three figures (no more, no less). Report the uncertainty of the results as described below.

Convert the mass of water contained in its volumetric flask. Determine the average volume and the 95% confidence interval.

If time permits, repeat the calibration if the 95% confidence intervals are higher than the tolerance of the 10 mL flask. Tabulate these results.

🔹 Indications of the volumetric flask

Description

The volumetric flask is a receptacle with flat base and pear shape. It has a thin and long neck with marks that they indicate the volume of liquids.

The label with the information essential over the instrument is located on the neck. This information is the volumetric capacity, the temperature with which the instrument should be handled and, of course, the mark of the manufacturer.

This instrument has a plug, made of plastic, tempered glass or cork, however, it is usually made with polypropylene.

This cap fits perfectly with the container mouth, avoiding accidents such as spills at the time of prepare the solutions.

It has a mark called a calibrator that represents the limit of liquid that the container allows. There is a distance of some consideration between the meter and the flask mouth, this allows the contents to be stirred when necessary.

👉 Types of flasks according to your precision

There are two types of flasks of according to the precision they can provide. First there are the ones used in the preparation of valued or standardized solutions. They are characterized by their
great accuracy. They are usually used in analytical chemistry laboratories.

On the other hand, there are those that provide less precision. These are used in the elaboration of solutions that do not require high levels of demand.

🌳 Kinds of flasks according to their volume capacity

There are containers from 1 ml up to 2 l. Usually, the measurements of these instruments are as follows: 25 ml, 50 ml, 100 ml, 200 ml and 500 ml.

❤ Types of flasks by color

Most of the jars are made of transparent borosilicate glass. However, it is possible to find an amber color that is used to make solutions susceptible to light, as happens with silver nitrate.

How to use it?

First of all, it must be cleaned thoroughly the flask and dry it. There can be no residue inside or drop of water well, this can alter the volume of the substance what it would cause errors at the time of measurement.

It is imperative that experiments with the volumetric flasks are carried out at a minimum of 20 °C and as maximum 25 ° C, since this instrumentation was created with the possibility of work under the indicated conditions.

Start by adding the solute (which it is pre-weighed). In case part of the solute adheres to the neck of the flask, this should be removed carefully by using a solvent. No however, it is preferable to ensure that the solute reaches the bottom directly.

Once 50% of the solvent has been added, the container must be stirred to dissolve the solute. It is important to be very careful when shaking it (not exceeding in force), you should also prevent the mixture from splashing up to the point.

Then the rest of the solvent is incorporated until the indicated mark is reached. The plug is placed and, then, it can be shaken with greater force until the mixture is homogeneous.

📌 Care of Volumetric Flasks

Flasks are equipment of special care should be taken because various conditions can affect its proper functioning.

As an example we could point to the next case: When heated to very high temperatures, it is possible that alter the container, this would cause the pressure to be lost when required for volume measurement. For this reason, it is important to avoid overheat it.

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