In the lab, knowing the equipment well and choosing it wisely is essential: this is part of good laboratory practice. It is a prerequisite in order to obtain reliable analysis results.
Among the equipment available in a chemistry lab, the glassware is very important. Several types of glassware exist.
The distinction is made between:
Regarding precision glassware, the distinction must be made between:
Furthermore, there is precision glassware to measure precise contained volumes (noted In) and precision glassware to measure precise delivered volumes (noted Ex).
In addition, depending on the level of precision of the glassware, there are two classes:
For some applications (e.g. with liquids that attack glass such as hydrofluoric acid), it is preferable to use plastic material instead of glass.
Several types of glass exist in glassware used in chemistry:
Standard glass: it is a soda-lime glass, made from silica SiO2 (about 74%), sodium oxide Na2O (13 %), lime CaO (7%), magnesia MgO (4%), and alumina (aluminium oxide) Al2O3 (2 %). As a result of its high coefficient of thermal expansion, this glass offers little tolerance to thermal shocks. It remains therefore seldom used for laboratory equipment intended for heating. However, it is easy to wet, and is therefore used widely for pipettes.
Borosilicate glass, very widely used in laboratories. This type of glass is acknowledged worldwide: ranked 3.3 DIN ISO 3585. It is made of silica SiO2 (80 %), boric oxide B2O3 (13 %), and small amounts of alkalis (sodium oxide Na2O potassium oxide K2O: 4 %) and alumina Al2O3 (2.3%). Its thermal expansion is moderate, therefore its tolerance to thermal shock is good. Its chemical tolerance to acids (except FH and H3PO4 ) is also good – however it does not tolerate bases very well.
Pyrex (or Duran) glass, also widely used in laboratories: it consists in a borosilicate glass but strengened, with thicker sides. It provides a great robustness as well as an extraordinary tolerance to mechanical and thermal shocks.