Chemistry Reference
In-Depth Information
The handling of alkaline metals is described in experiments E5.3-E5.10, for
reactions with air, water and halogens. Important classroom experiments on essen-
tial school topics can be taken from the experimental literature (see [
10
-
14
]). In
case the students are supposed to run experiments with special effects individually,
careful supervision is needed due to the specific safety hazards.
hile working on school experiments the students will get to know a multitude of
laboratory equipment. The knowledge of equipment is important for planning
experiments for chemistry classes or for running spontaneous experiments,
supplementing the classroom discourse. For another thing, it is advantageous to be
able to organize the school equipment appropriately. Attaching analytical instruments
to a computer makes it possible to collect a series of tests and simultaneously get a
graphic representation. With adequate hardware and software data may be collected
and analyzed in multiple ways. Since hardware and software develop quite fast, no
current literature and equipment list will be given at this stage.
Safety and Disposal:
It is self-evident that accidents should not happen during
experimentation in laboratory exercises and that carelessness has to be avoided.
Laboratory supervisors and teachers have to point out dangers and specific safety
measures to all students. A good theoretical and practical-experimental education
of chemistry teachers at universities and seminars is the best guarantee for appro-
priate and accident-free experimentation.
Future teachers need to be familiar with the compilation of chemicals and safety
installations, the place and handling of fire extinguishers, fire blanket, sand, safety
shower and first aid box. They have to be certain that an adequate disposal of
chemical waste is possible or they have to set-up the facilities for it.
The different “Guidelines on Hazardous Substances” define the labeling of all
containers for chemicals with standardized danger symbols (see Fig.
5.4
) as well as
risk and safety statements (R and S phrases). The “Technical Rules for Hazardous
Substances” (in Germany: TRGS 450) regulate the handling of hazardous
substances in schools. These rules state that the following substances may be
used in teacher experiments, but not in student experiments:
- Very toxic substances (T+), e.g. carbon disulfide, nitrobenzene, carbon tetra-
chloride, white phosphorus, metal cyanides, etc.
- Carcinogenic or teratogenic substances (T), e.g. benzene, chromium (VI) com-
pounds in the form of dusts and aerosols, 1,2-dibromoethane, nickel, cobalt, etc.
- Explosive substances (E), e.g. black powder and mixtures of oxidizable
substances with potassium chlorate or sodium chlorate, etc.
- Mixtures of substances that contain pathogens like pathogenic bacteria and
fungal cultures, fecal effluent, etc.
Disposal:
There are specific instructions for teachers: they have to make them-
selves familiar with those regulations on hazardous substances and their disposal.
They start with considerations of experiments that do not produce hazardous waste
at all. These considerations can happen with the students and be part of their
environmental education.
