Work with Glass

Tubes up to 10-12 mm in diameter can be cut in this way. When properly notched, a tube breaks easily, forming clean edges without burrs. To cut wider tubes, tie a thick thread wetted with ethonol around the notched spot. Ignite the thread, and the glass at this spot will crack smoothly. 

Tube Bending. To bend a glass le for i tube, heat a part of it about five 

Drawing out a Tube End and Making Capillaries. To draw out the end of a tube (Fig. 25c) or a capillary (Fig. 25d), heat the tube 

Sealing of Tubes. To seal a tube, draw out its end and cut off the superfluous part. Next, while constantly rotating the tube, heat 

Usually a thickened sealed end is obtained, and it can easily crack. To avoid a thickened tube end, remove it from the flame after sealing and carefully blow air into the cold part of the tube until a properly rounded end is obtained. 

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Basic Glassworking Working with Glass Tubing Cutting glass tubing... 

There are many brilliant men and women who are excellent teachers and scientists, can analyze the most complex data, and can draw the most complex molecules or mathematical equations. Yet, many of these same people cannot communicate the shapes of even simple items on a piece of paper. In addition to this complication, when an object is made of glass, new complications are created. These new problems typically derive from the fact that working with glass is like working with no other material on earth. Thus, the average person will try to rationalize construction with materials they are more familiar with, such as wood or metal. In addition, it is unlikely that this average person will have had the opportunity to learn the parameters and limitations of glassware construction. 

Researchers working with glasses often think of acid-base reactions in terms of oxide donors and oxide acceptors. The oxide ion is... 

The amateur chemist must be able to work with glass. A knowledge of the manipulation of glass in the setting-up of various combinations of apparatus in the performance of certain experiments is quite necessary. 

Commercial solid-state potential measuring devices based on the type of op-amp described are often called pH or plon meters and are designed to work with glass pH electrodes, ion selective electrodes, and other indicator electrodes described earlier. Research quality plon meters have built-in temperature measurement and compensation, autocalibration routines for a three-point (or more) calibration curve, recognition of electrodes (so you do not try measuring fluoride ion with your pH electrode ), and the ability to download data to computer data collection programs. The relative accuracy of pH measurements with such a meter is about +0.005 pH units. Meters are available as handheld... 

One of the major simplifications adopted in chemistry is to focus on substances. This is a simplification because, in our normal environment, few of the materials we commonly come across are stricdy substances in the chemical sense. Figure 1.1 sets out the relationship between some key ideas in chemistry. So where matter is a general term for stuff, we tend to use the term materials for well defined samples of stuff that we can work with - glass, wood, sodium carbonate (washing soda), poly(ethene), diamond, sea water, paint, etc. From a technological perspective, these materials may have a similar status (different types of stuff that can be obtained, worked in various ways or used in different applications). 

Working with glass equipment under pressure... 

Recommendations for safe working with glass fibre were published in April 1995 by the European Glass Fibre Producers Association (AFPE). Brussels. They concluded the following. 

PT 2—Systems Course Description Study of common process systems found in the chemical process industry, including related scientific principles. Includes the study of pumps and compressor systems, heat exchangers and cooling towers, boilers and furnace systems, distillation systems, reaction systems, utility systems, separation systems, plastics systems, instrument systems, water treatment systems, and extraction systems. A hands-on lab gives students an opportunity to work with glass bench-top distillation units, start up and shut down a debutanizer unit from a computer console, and operate a distillation pilot plant. 

Figure 1.10 Working with glass tubing. The worker is using a tubing guard and wearing leather gloves. (Source National Institutes of Health.)...

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