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Equipment

Gas Syringe

Summary

A glass syringe used for gas collection.

Operation

Gas syringes are commonly used for collecting gases, measuring the amount of gas produced in an experiment or for inserting a gas into a closed system.

Typical gas syringes consist of two parts, an inner plunger and an outer sleeve. Where the two parts touch, the surface is usually ground so that the gap between them is as close as possible, creating a near gas tight seal.

Glass syringes are easily damaged if dropped or used incorrectly which may affect their performance. Because the two parts of each syringe are created together, the parts should not be interchanged with others. Even if they appear to be the same size, tiny deviations could cause a gap where gas could escape or could result in a fit which is too tight, causing wear.

Before use, make sure that the plunger can be inserted using as little force as possible. The plunger should move freely with little effort. If it appears to stick, try cleaning and polishing the parts. A sticky syringe could adversely affect experiments where gas is collected as the pressure created by a reaction may not be enough to move the plunger a relative distance, resulting in an incorrect reading.

Syringes should be carefully cleaned after use with detergent to remove any particles. The ground surfaces should be dried with a lint-free cloth to ensure no debris if left which could end up scratching the glass.

Gas syringes can be used for liquids, especially where their larger size allows a greater volume of liquid to be inserted or withdrawn. If liquids are to be used, thorough cleaning is essential after use, in fact it may be sensible to have separate "liquid only" and "gas only" syringes to make life easier.

A length of string can be attached between the two parts which not only helps keep them together during storage but also means that the plunger cannot accidentally fall out of the sleeve.

Safety

 CautionThe contents of this page are for information only. Please refer to CLEAPSS, SSERC or ASE safety advice and/or publications before undertaking any preparation, practical experiment or using any equipment featured on this site or any other.