Tared Container

A tare is the mass of an empty sample container. Taring is the process of setting a balance to read zero In the presence of the tare. 

Substances Control Act (TSC A). In May 2006, the Occupational Safety and Health Administration (OSHA) implemented new, stricter regulations regarding workplace exposttre to chromates especially hexavalerrt chrome. Polymeric coating systems containing tare earth compound inhibitors that provided corrosion inhibition in a similar manner have been developed. Replacement of the chromate compotmds used in the primer coating with tare earth-based material removes >95 wt% of the hexavalent chromium contained in the coating system. 

The tare weight (sometimes called stencil weight because it is cut into the cylinder metal) is the total weight of the cylinder and contents, but does not include a removable valve protection cap, if such is used. The saturation gas part of the tare weight is a calculated number which allows for the 11.4 g of acetylene required to saturate each 453.6 g of contained acetone at atmospheric pressure. The correct tare weight is an absolute necessity to the safe charging of acetylene cylinders. 

The product in M is treated with small amounts of solid sodium bicarbonate to neutralize any acid present. The cold liquid is filtered through a small filter into a 1500-cc. distilling flask containing about i g. of hydroquinone. It is then distilled into a tared dark bottle containing about i g. of hydroquinone. The yield of product boiling at 52.5-55.5° (Note 5) obtained from 1200 g. (13 moles) of dry glycerol is 240-350 g. (33-48 per cent of the theoretical amount). 

Three moles of chlorine (212.7 g.) is condensed in a tared flask cooled by a dry ice-acetone bath (Note 4). This flask is then connected to the gas inlet tube of the chlorination apparatus, and the cooling bath surrounding the chlorine container is removed. After about 2 hours the chlorine has all been absorbed by the reaction mixture (Note 5). 

Lithium wire purchased from the Lithium Corporation of America, Inc. was used. The wire was cut in 2.5-5.0-cm. pieces, washed free of the protective oil with ether, and weighed by transferring quickly to a tared beaker containing mineral oil. The lengths of wire were again washed in a beaker of ether and then held with forceps over an open neck of the reaction flask (positive nitrogen flow), cut with scissors into 3-4-mm. pieces, and allowed to fall directly into the flask. 

Methylamine hydrochloride method. Place 100 g. of 24 per cent, methyl-amine solution (6) in a tared 500 ml. flask and add concentrated hydrochloric acid (about 78 ml.) until the solution is acid to methyl red. Add water to bring the total weight to 250 g., then introduce l50 g. of m%a, and boil the solution gently under reflux for two and three-quarter hours, and then vigorously for 15 minutes. Cool the solution to room tempara-ture, dissolve 55 g. of 95 per cent, sodium nitrite in it, and cool to 0°. Prepare a mixture of 300 g. of crushed ice and 50 g. of concentrated sulphiuic acid in a 1500 ml. beaker surrounded by a bath of ice and salt, and add the cold methylurea - nitrite solution slowly and with mechanical stirring and at such a rate (about 1 hour) that the temperature does not rise above 0°. It is recommended that the stem of the funnel containing the methylurea - nitrite solution dip below the siu ace of the acid solution. The nitrosomethylurea rises to the siuface as a crystalline foamy precipitate. Filter at once at the pump, and drain well. Stir the crystals into a paste with about 50 ml. of cold water, suck as dry as possible, and dry in a vacuum desiccator to constant weight. The yield is 55 g. (5). 

When collecting urine samples from test subjects, the tare weight of the collection vessel must be recorded before giving the container to the volunteer. The urine samples must be kept cold during the collection process. To do this, the samples should be kept in Coleman-type coolers with blue ice in the bottom. The blue ice should be frozen solid prior to placement in the cooler. Usually 3-5 pieces of blue ice should be used per cooler. 

In this method a container of sediment is thoroughly stirred and mixed. 20g of sediment is taken in a tared 250ml beaker, placed in a vacuum oven at 70°C and dried to constant weight. The weight of dried sediment is calculated. 

In the event that the tare feature of a balance is not used, the container weight must be subtracted before Equation (3.4) can be used. See Workplace Scene 3.1. 

In any case, the sample is usually contained in a crucible (prepared in advance by ignition without a sample) and placed in the oven or over the Meker burner for a specified period of time or to a constant weight, as in the loss on drying. The calculation is also similar to loss on drying, and the weight of the crucible will need to be subtracted if the tare feature of a balance is not used. 

Tare a beaker or other container and weigh, to the nearest 0.1 g, a sample of the sand that would occupy about half the volume of the top sieve. 

A tared 500-ml. round-bottomed flask is fitted with a vacuum take-off, and the entire assembly is connected through an adaptor containing a stopcock to an inverted cylintler of... 

After this period, the dropping funnel and the vacuum takeoff are replaced by the short-path distillation assembly shown in Figure 2. The system is protected by a Drierite tube and the benzene is distilled under reduced pressure (water aspirator). After the benzene is removed, the benzene-containing receiver is replaced with a clean, dry flask, and the system is connected to an eflScient vacuum pump. The pressure in the system is reduced to 0.02 mm., and the flask is immersed deeply in an oil bath (Figure 2) heated to about 200°. After about 1 ml. of fluid forerun is collected, the diethylaluminum cyanide distils at 162° (0.02 mm.) (Note 7) and is collected in a tared 200-ml. receiver by heating the side arm and the adaptor with a stream of hot air or an infrared lamp (Note 8). After all the distillate is collected in the receiver (Note 9), dry nitrogen is admitted to the evacuated apparatus and the receiver is stoppered and weighed. Diethylaluminum cyanide is obtained usually as a pale yellow syrup (Note 10) in 60-80% yield (26.7-35.6 g.) (Note 11). 

Class and porcelain are particularly susceptible to adsorption of atmospheric moisture on exposed surfaces. Containers to be heated in gravimetric procedures (e.g. oven-dry matter or ash content) should therefore be pre-heated to the same temperature as that procedure and cooled in a desiccator before measuring the tare weight. 

Determination of Aluminum. Weigh accurately a sample calculated to contain 0.4g of TNT into a tared sintered glass filtering crucible, medium porosity, 30-ml capacity. Extract on a Fisher filtrator with ethylene chloride (purified... 

Alternate Method of Analysis. Grade A 4.4.3.3.1 Determination of RDX + Nitrocellulose. Weigh accurately a sample calculated to contain between 0.35 and 0.40g of TNT into a tared 100-ml beaker. Add 20ml of RDX saturated benzene to the beaker. The prepn of the RDX saturated benzene is described in 4.4.3.5.5. Cover beaker with a watch glass and place on a steam bath for 30 mins, swirl soln frequently. (An oscillating hot... 

---