Properties of Glassware

Properties of Glassware

Laboratory glassware is produced from hundreds of commercial glasses, but by far the low expansion borosilicate glasses are the most ideal for most laboratory applications. Because of their low coefficient of expansion and their high resistance to chemical attack, borosilicate lab glassware is used to manufacture such lab items as beakers, flasks, kettles, test tubes, ground joints and other scientific products. With proper care, they will withstand nearly all temperatures used in normal laboratory use.

Borosilicate glass is inert to almost all materials except hydrofluoric acid, phosphoric acid, and strong hot caustic solutions. Of these hydrofluoric acid has the most serious effect, even when it is present in very low concentrations of parts per million in solution.

Phosphoric acid and caustic solutions cause no problems when cold but at elevated temperatures corrosion may occur. For example, in case of caustic solutions up to 30% concentration can be handled safely at ambient temperature.

Whenever heat and agitation are being applied in the laboratory such as with beakers placed on stirring hot plates or boiling flasks heated within heating mantles and overhead stirrers, care should be taken to use products that are manufactured from borosilicate glass.

Well known brands such as Pyrex, a Corning trade name; Bomex, which is sold by Vee Gee Scientific; Kimax, which is a Kimble trade name; and other manufacturers are available thorough laboratory supply companies such as The Lab Depot, Inc., Fisher Scientific, and others.

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