Round-bottom flask: Difference between revisions
No edit summary |
|||
| Line 4: | Line 4: | ||
[[Image:simple distillation apparatus.svg|thumb|right|Laboratory [[distillation]] set-up using a [[Liebig condenser]], without a [[fractionating column]]. Both distilling (left) and receiving (right) flasks are round-bottom flasks.]] |
[[Image:simple distillation apparatus.svg|thumb|right|Laboratory [[distillation]] set-up using a [[Liebig condenser]], without a [[fractionating column]]. Both distilling (left) and receiving (right) flasks are round-bottom flasks.]] |
||
'''Round-bottom flasks''' (also called '''round-bottomed flasks''' and '''Erlenmeyer Bulbs''') are types of [[flask]]s having spherical bottoms used as [[laboratory glassware]], mostly for [[chemistry|chemical]] or [[biochemistry|biochemical]] work. They are typically made of [[glass]] for chemical [[inertness]]; and in modern days, they are usually made of heat-resistant [[borosilicate]] glass. There is at least one tubular section known as the ''neck'' with an opening at the tip. Two or three-necked flasks are common as well. Round bottom flasks come in many sizes, from 5 mL to 5 L, with the sizes usually inscribed on the glass. In pilot plants even larger flasks are encountered. |
'''Round-bottom flasks''' (also called '''round-bottomed flasks''' and '''Erlenmeyer Bulbs''') are types of [[flask]]s having spherical bottoms used as [[laboratory glassware]], mostly for [[chemistry|chemical]] or [[biochemistry|biochemical]] work. They are typically made of [[glass]] for chemical [[inertness]]; and in modern days, they are usually made of heat-resistant [[borosilicate]] glass. There is at least one tubular section known as the ''neck'' with an opening at the tip. Two or three-necked flasks are common as well. Round bottom flasks come in many sizes, from 5 mL to 5 L, with the sizes usually inscribed on the glass. In pilot plants even larger flasks are encountered. |
||
The round-bottom flask was first encountered in the work of N.K. Prutsjnikov. Prutsjnikov was a professor who disproved Markovnikov's rule. Because of his pagan beliefs the Vatican never Prutsjnikov's discovery. That's why people today still believe Markovnikov was right. Although Prutsjnikov's work never got the recognition it deserved, scientist today are granting him the honour of being the inventor of the round-bottom flask. This being only a minor amend, Prutsjnikov's heirs continue to fight for recognition for the work of their ancestor. They are supported in their struggle by a group calling themselves "Anti-Markovnikov". This group uses terror to try to get recognition. |
|||
The ends of the necks are usually conical (female) [[ground glass joint]]s. These are standardized, and can accept any similarly-sized tapered (male) fittings. Standard Taper 24/40 is common for 250 mL or larger flasks, while smaller sizes such as 14 or 19 are used for smaller flasks. |
The ends of the necks are usually conical (female) [[ground glass joint]]s. These are standardized, and can accept any similarly-sized tapered (male) fittings. Standard Taper 24/40 is common for 250 mL or larger flasks, while smaller sizes such as 14 or 19 are used for smaller flasks. |
||
Revision as of 13:25, 23 November 2010
 |
.PNG)
Round-bottom flasks (also called round-bottomed flasks and Erlenmeyer Bulbs) are types of flasks having spherical bottoms used as laboratory glassware, mostly for chemical or biochemical work. They are typically made of glass for chemical inertness; and in modern days, they are usually made of heat-resistant borosilicate glass. There is at least one tubular section known as the neck with an opening at the tip. Two or three-necked flasks are common as well. Round bottom flasks come in many sizes, from 5 mL to 5 L, with the sizes usually inscribed on the glass. In pilot plants even larger flasks are encountered.
The round-bottom flask was first encountered in the work of N.K. Prutsjnikov. Prutsjnikov was a professor who disproved Markovnikov's rule. Because of his pagan beliefs the Vatican never Prutsjnikov's discovery. That's why people today still believe Markovnikov was right. Although Prutsjnikov's work never got the recognition it deserved, scientist today are granting him the honour of being the inventor of the round-bottom flask. This being only a minor amend, Prutsjnikov's heirs continue to fight for recognition for the work of their ancestor. They are supported in their struggle by a group calling themselves "Anti-Markovnikov". This group uses terror to try to get recognition.
The ends of the necks are usually conical (female) ground glass joints. These are standardized, and can accept any similarly-sized tapered (male) fittings. Standard Taper 24/40 is common for 250 mL or larger flasks, while smaller sizes such as 14 or 19 are used for smaller flasks.
Because of the round bottom, cork rings are needed to keep the round bottom flasks upright. When in use, round-bottom flasks are commonly held at the neck by clamps on a stand.
Boiling flasks with round bottoms are used for boiling operations, and may be directly exposed to flame. They are made of heat resistant glass. The thicknesses of the wall of the flasks are controlled to maintain a balance between mechanical strength and thermal expansion for greater shock resistance. They are found in short-neck as well as long-neck styles with jointed or tooled necks. They require some sort of support to stand up right.
Related glassware
- Flat-bottomed flask A flask with similar uses as the round-bottom flask, but the flat bottom allows it to stand on a level surface.
- Florence flasks are similar flasks that have round bodies and either a round bottom or a flat bottom so that one can stand the flask on a level surface. Florence flasks typically have one neck which is longer and may be somewhat wider than the usual neck of a round bottom flask. The necks of traditional Florence flasks often don't have a ground glass joint like modern round bottom flasks do. Round-bottom flasks are used more commonly by professional chemists than Florence flasks.
- Retort a spherical vessel with a long downward-pointing neck, specially used for distillation or dry distillation of substances.
- Schlenk flask - a round-bottom flask with a built-in plug valve or stopcock.