Careful Transfusion of Liquids
Liquids must be poured carefully, leaning the neck of one vessel against another to avoid splashing. Liquids can be poured using a glass wand: the liquid flows evenly through it, and there is no splashing. If the conditions of the experiment require large amounts of substances, use flasks or glasses. It is convenient to measure small volumes of liquids with pipettes (Texas Education Agency, 2023f). When dissolving substances in liquids, one should stir the mixture gently, using rotational movements of the vessel or stirring the liquid with a glass stick. One can not close the opening of the vessel with fingers or palms and then stir it, as the substance can cause chemical burns.
Techniques for Handling a Laboratory Tripod
A laboratory tripod is a device with which many different experiments can be performed. Due to its versatility in both glass and porcelain dishes, various devices necessary for experiments can be fixed in the tripod. With the help of a foot in a tripod, one can fix various glassware. A porcelain bowl is usually placed on the tripod ring. The glassware is fixed in the foot of the tripod at a distance of several centimeters from the opening of the test tube or flask (Texas Education Agency, 2023e). With the help of turns of the foot, the vessel is fixed into the coupling at the angle necessary for the experiment (Texas Education Agency, 2016). When fixing glassware in the tripod foot, it is important to remember that the glass is quite fragile. To avoid cracking the glass, do not tighten the foot screw too tightly. The porcelain bowl does not need to be fixed at all; it is enough to put it in the recess of the tripod ring.
Working with Bulk Materials
In a chemical laboratory, all substances are stored in tightly sealed jars, usually made of glass. Before starting the experiment, the required amount of substance is taken from the jar. The jar with the remainder of the substance is immediately removed and stored in storage (Texas Education Agency, 2023c). The lid of the jar from which the substance is taken must be placed on the table with the thread facing up. This is necessary so that the particles of the substance on the lid do not fall on the table. Bulk substances must be poured with spoons or a bent sheet of paper to avoid spillage. If the pieces of the substance are too large, one cannot throw them into a glass vessel, as the glass may crack from the impact.
Detection of Substance Smell
To detect the smell of the substance, it is necessary to place the opening of the vessel at the level of the face, at a distance of 10-15 cm (Texas Education Agency, 2023b). With the help of palm strokes, one should capture the air containing the smell and direct it to the nose. In order to avoid chemical burns of the nasopharyngeal mucosa, one should not lean against the vessel to inhale the smell.
Wearing Special Protective Clothing
When working in a chemical analysis laboratory, there is always a risk of contamination and contact with the skin and mucous membranes of aggressive chemicals. To provide specialists with comfortable and safe working conditions, it is necessary to wear a special protective uniform (Texas Education Agency, 2023a). It is necessary to wear a set of workwear consisting of a suit or robe made of a material resistant to acid and alkaline solutions and an apron made of polymer materials (Texas Education Agency, 2023d). In addition, gloves made of polymer materials or rubber are necessary to protect against aggressive substances, as well as personal protective equipment for the eyes and respiratory organs.
References
Texas Education Agency (2023a). Laboratory and field investigations FAQs.
Texas Education Agency (2023b). Safety information and resources.
Texas Education Agency (2023c). Safety standards.
Texas Education Agency (2023d). TEA safety laws and rules.
Texas Education Agency (2023e). TEA science facilities best practices.
Texas Education Agency (2023f). TEA Texas safety standards.
Texas Education Agency (2016). Chemical safety 2016.