Common Lab Glassware and Uses

1. Glassware for Qualitative Uses

1. Beakers
   1. The beaker is one of the most common pieces of glassware in the laboratory. It is a simple cylindrical container used to hold solids and liquids with sizes ranging from very small (10 mL) to very large (4,000 mL). It has a lip for ease of pouring and decanting liquids. The graduations are approximate, but very useful when exact volumes are not needed.
2. Flasks
   1. Flasks are designed so the contents can be swirled without spilling. They are also easily fitted with stoppers and often have the stopper size written directly on the flask.
   2. Erlenmeyer Flask
      1. The most common of all flasks, the Erlenmeyer flask has a flat bottom with approximate graduations. The flat bottom allows the Erlenmeyer flask to be directly heated and used in simple reflux (boiling) and condensation procedures.
   3. Florence Flask
      1. The Florence flask is a hybrid between the round bottom and the Erlenmeyer flask and ranges from a few hundred milliliters to a few liters in size. Florence flasks can have either a flat bottom or a round bottom, so applications vary from direct heating to using a heating mantle. It does not have a ground glass joint, so a stopper is used to seal the container. The rounded shape is better for applications that involve boiling.
3. Test Tubes
   1. Test tubes are relatively small cylindrical vessels used to store, heat, and mix chemicals. While the test tube comes in specific sizes, it's typically used in qualitative observational procedures.
4. Watch Glass
   1. The watch glass is used when a high surface area is needed for a small volume of liquid. This is common for crystallizing and evaporating, as well as other qualitative procedures. Watch glasses can also be used as covers for beakers, but not flasks.
5. Crystallization Dish
   1. The crystallization dish is a hybrid between a watch glass and the Petri dish (common in biological procedures). It has a low height-to-width ratio, which means the sides are very low compared to the width of the vessel. This allows for high surface areas for evaporation, but the crystallization dish is more commonly used as a short-term container for liquids in a variety of bath processes (water, acid, or oil).

2. Glassware for Measuring

1. Graduated Cylinder
   1. The graduated cylinder is used to measure a semi-precise volume of liquid. While it is not as precise as volumetric glassware, it is much more accurate and precise than a beaker or flask (to within 1%). Volumes are measured to the bottom of the meniscus for aqueous solutions and the top of the meniscus for non-aqueous hydrophobic solutions. Graduated cylinders are general-use pieces of "TD" glassware, where the delivery volume is important. Higher levels of accuracy require volumetric glassware.
2. Volumetric Glassware
   1. Used for making standardized (high precision) solutions, where precision is known to four significant figures.
   2. Flasks
      1. Volumetric flasks are a mainstay when preparing any standardized solution. Since volumes are not necessarily additive, the volumetric flask is used to make solutions of precise volumes. The etched mark on the neck of the glassware signifies the volume to high precision at the specified temperature. A solution is prepared by adding enough solvent to dissolve the solute, then the solute is added and dissolved. The solution is then diluted to the mark using the solvent. The solution is mixed throughout the dilution process and sometimes requires being placed in an ice bath in the case of exothermic dissolution (typically strong acids or bases). Volumetric flasks range in size from 1 mL to 4,000 mL and larger.
3. Pipettes
   1. Volumetric pipettes are known for high precision, like volumetric flasks, but are used to dispense liquids, typically in the preparation of solutions in a volumetric flask. The pipette also has an etched mark denoting a precise volume, and the solution is drawn into the pipette using a pipette bulb, never by mouth.
4. Micropipettes
   1. Micropipettes are a specialized class of volumetric pipettes used for very small volumes from 1 µl to 1,000 µL. The micropipette uses plastic disposable tips, but these can be re-used under appropriate situations. Most micropipettes have an adjustable range of volumes using separate withdraw and dispense actions on the pipette body. The mechanism for adjusting, determining volume limits, and ejecting disposable tips varies by manufacturer.
5. Burettes
   1. The burette is an analytical piece of glassware used to dispense variable (but precise) volumes of liquids. Commonly found in analytical chemistry, the burette is used in a variety of titration experiments.

3. Procedural Glassware

1. Round-bottom (Boiling) Flasks
   1. Round-bottom flasks, or boiling flasks, are typically found in synthesis experiments, since the round shape allows for even heating and stirring. The neck typically has a female ground-glass joint and can be attached to condensers and other pieces of glassware. To prevent spills, the solution volume should not exceed 50% of the flask volume. Sizes range from 50 mL to 20,000 mL.
2. Separatory Funnel
   1. While most common to the organic chemistry lab, the separatory funnel is used to separate liquids of different densities and solubilities. The bottom of the separatory funnel is very narrow and leads to a stopcock, allowing for precise separations of liquids, while the top is very wide for ease in shaking and mixing.
3. Filter (Büchner) Flask (used for vacuum filtration)
   1. The filter flask looks like an Erlenmeyer flask, but has a hose barb near the top to attach a vacuum hose. The flask typically has thicker walls than an Erlenmeyer due to the reduced pressure (vacuum) used with the flask. Vacuum (Büchner) funnels fit into the neck of the flask using a rubber collar or a 1-hole rubber stopper.
4. Funnels (used for filtering and transferring)
   1. Traditional funnels used for gravity filtration have a wide cone-shaped body, for adding and filtering solutions, and a long narrow stem, for delivery into a flask. Filter paper is folded into a cone shape, inserted into the funnel, and wetted with a solvent (typically water). The powder funnel has a wider stem designed for dispensing solids and viscous liquids. Filter paper is only used in conjunction with the filter funnel.
5. Ceramics
   1. Büchner Funnel
      1. The ceramic Büchner funnel fits into the filter (Büchner) flask using a rubber cone or 1-hole rubber stopper. The funnel is typically made of ceramic with pin-sized holes in the flat bottom. Filter paper is placed on top of the holes and wetted with solvent (water) to prevent solids from getting under the filter paper.
   2. Crucible
      1. A crucible is made of ceramic and holds small amounts of chemicals during heating at high temperatures. Depending on the specific type, the crucible can withstand temperatures above 1,000 °C and is used in conjunction with a Bunsen burner or furnace. Common uses include heating a hydrated solid to remove water or combusting a compound to determine organic content.
   3. Mortar and Pestle
      1. While the mortar and pestle originated in chemistry (and alchemy) laboratories, it is more common in pharmacology, biology, and culinary applications. Made of ceramic or stone, materials are placed in the bowl-shaped mortar and ground and crushed using the pestle.