In the lab, knowing well the equipment and choosing it wisely is essential: it is part of the good practice. It is a prerequisite in order to obtain reliable analysis results.
Among the equipments available in a chemistry lab, the glassware is very important. Several types of glassware exist.
The distinction is made between:
About the precision glassware, the distinction must be made between:
Furthermore, there is a precision glassware to measure a precise contained volume (noted In, for Inside) and a precision glassware to measure a precise delivered volume (noted Ex, for Expulse).
In addition, depending on the level of precision of the glassware, there are two classes:
For some applications (e.g. with glass-attacking liquids such as hydrofluoric acid), it is better 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 sparsely used for laboratory equipment intended for heating. However, it is easy to wet, and is therefore very used for pipettes.
Borosilicate glass, very 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 well the bases.
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.