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Laboratory flasks are lab vessels with wide  bodies and narrow, tubular necks. They can be used for mixing, measuring, and heating chemicals, samples, and solutions.  A type of labware, laboratory flasks are made of glass or plastic and specified by volume. Often, a stopper or cap is used to seal the opening at the neck. 

Types of Lab Flasks

The GlobalSpec SpecSearch database provides information about three types of laboratory flasks.

  • Volumetric flasks are used to prepare chemical solutions of a fixed volume with great accuracy. Typically, these products are graduated for ease of measurement.

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  • Erlenmeyer flasks are flat-bottomed or conical flasks that are relatively inexpensive and very commonly used. They are sometimes classified as reagent flasks.

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  • Boiling flasks or Florence flasks are used to distill liquids. Claisen flasks are a type of lab flask that is used for boiling. They have two stacked stillheads: one for holding the capillary and the other for holding the thermometer.

Image Credit: Laboratory World

Lab Flask Materials

Laboratory flasks can also be categorized by material of construction. There are two basic types: glass and plastic. There are also various subtypes.

Glass Flasks

Glass flasks are made generally of fused silica, borosilicate or quartz glass, or proprietary commercial glasses such as KIMAX® (Kimble Chase) or Pyrex® (Corning). When selecting products, buyers need to consider their application requirements. For example, borosilicate glass flasks can withstand thermal shock and chemical attack. Fused silica is suitable for applications that require good, long-term thermal stability.

Plastic Flasks

Plastic flasks are made of fluoropolymer resins and elastomers, rubber, polyamides, commonly-used polymers,  and proprietary plastics. As with glass flasks, buyers of laboratory glassware need to consider their application requirements when selecting products. For example, EPDM flasks provide good resistance to ultraviolet (UV) light, but are unsuitable for petroleum-related applications because of their poor resistance to fuels.

Product Specifications and Features

In addition to material, volume is an important specification to consider when selecting lab flasks. Buyers need to source products that are large enough to contain chemical samples, and may also require products that have a handle or are designed for heavy-duty use. Some flasks, typically those made of less expensive glass or plastic, are disposable and designed for one-time use.

Resources

Chemistry World - Classic Kit: Claisen's Flask

Laboratory Equipment World - Boiling/Florence Flasks