Weighing bottle test

Figure 7. Formaldehyde liberation from particleboards and CH20-sorbed wood at 27°C and 33 percent relative humidity (RH) weighing bottle test with -80 mesh materials (o Southern pine impregnated with pH 2 tartaric acid and vapor-equilibrated with CH20/salt solution at pet RH O as before except heated 4 min. 16O°C after CH2O sorption 0 urea-formaldehyde particle board (b) phenol-formaldehyde particleboard, values approximate P = Perforator value at indicated moisture content (MC)).

Interpretation for Comminuted Systems. The similarities and differences noted for the kinetics of formaldehyde removal from UF and PF particleboards and from formaldehyde-sorbed wood are brought out more clearly by plotting relative formaldehyde losses versus time. Loss ratios, i.e., formaldehyde loss by any material divided by the UF board loss at the same time, are shown in Figures 10 and 11 included in Figure 10 are analogous ratios for resin data from formaldehyde liberation (weighing bottle test) and formaldehyde elution by toluene experiments (10). Examination of the data leads to the following additional comments ... 

Figure 10. Formaldehyde loss ratios at 20 percent relative humidity for various materials. (Formaldehyde removed from a material divided by that removed from urea-formaldehyde particleboard. Board elution by nitrogen. Resin liberation by weighing bottle test. PF = phenol-formaldehyde) (ML85 5437)...

WB = weighing bottle test PF = phenol-formaldehyde aq = water extraction test at pH 3. All materials -80 mesh. Southern (So.) pine impregnated with pH 2 tartaric acid and CH2O vapor-sorbed.) (ML85 5438)... 

Hydrolysis (or saponification) of n-butyl acetate. Boil 4-5 g. of n-butyl acetate (Section 111,95) with 50 ml. of 10 per cent, sodium hydroxide solution under reflux until the odour of the ester can no longer be detected (about 1 hour). Set the condenser for downward distiUation and coUect the first 10 ml. of distillate. Saturate it with potassium carbonate, aUow to stand for 5 minutes, and withdraw all the Uquid into a small pipette or dropper pipette. AUow the lower layer of carbonate solution to run slowly into a test-tube, and place the upper layer into a small test-tube or weighing bottle. Dry the alcohol with about one quarter of its buUr of anhydrous potassium carbonate. Remove the alcohol with a dropper pipette and divide it into two parts use one portion for the determination of the b.p. by the Siwoloboff method (Section 11,12) and convert the other portion into the 3 5-dinitrobenzoate (Section III, 27) and determine the m.p. 

After immersion, test pieces are usually cooled to room temperature (although the standard does not mention this), which is best done by transferring them to a fresh portion of the test liquid. Surplus test liquid must be removed from the surface but no evaporation should be allowed before measurement of change in property. For very volatile liquids this means testing quickly or, for mass measurement, rapidly transferring the test piece to a weighing bottle. 

When the reaction terminates, cool the retort in a chlorine stream, then displace the chlorine with a stream of dry carbon dioxide. Rapidly disconnect the retort from the wash bottles and remove the remaining unreacted metallic iron through its neck. Pour out the iron chloride through the tubulature of the retort into a preliminarily weighed dry test tube drawn out at its middle. Immediately seal the tube wear eye protection ) and weigh it. Write the equation of the reaction. Calculate the yield in per cent. 

As copper dissolves in the nitric acid, add new portions of copper shavings to it. When the entire selenium is oxidized, disconnect the flask with nitric acid, and suck a stream of dry air through the apparatus. Extract the prepared selenium(lV) oxide from the tube, put it into a weighing bottle, and weigh it. Determine the yield ip per cent. Write the equations of the reactions. Test the properties of selenium(IV) oxide (see p. 116). Hand in the preparation to your instructor. 

When the reaction terminates (how can you determine this ), cool the apparatus in a stream of ammonia. Disconnect the two-neck bottle and use a water-jet pump to remove the ammonia from the apparatus. Extract the boat and put it into a weighing bottle for boats or into a test tube closed with a stopper. Weigh it. Determine the yield of magnesium nitride. 

Perform desolvation ofthemanganese chloride in a vacuum produced by a water-jet pump while carefully heating the test tube with the flame of a burner. Transfer the product into a weighed weighing bottle, weigh it, and calculate the yield in per cent. 

Berkhout Stability Test, designed in the artillery laboratory at Hembrug,Holland, consists in heating samples of NC or propints in weighing bottles at 95°, 105° or 110° and noting the loss of wt in a definite period(such as 72 hrs), as well as the time required for evoln of red fumes. The heating is conducted in a specially designed thermostatically controlled oven. Two models of such ovens are described in Ref 1 (Compare with Jacque Test and with Sy Test) Refs 1)J.D.Berkhout,SS 17,33 4(1922) CA 16, 2602(1922) 2)Reilly(1938),85... 

Loss on Heating Heat about 1 g of sample, accurately weighed, in a crucible tared in a stoppered weighing bottle, to constant weight at 400° to 500°. Cool in a desiccator, transfer to the stoppered weighing bottle, and weigh. Selenium Determine as directed in Method II under Selenium Limit Test, Appendix IIIB, using 200 mg of sample. 

Cyclohexane should be introduced into the inner test tube from a weighing bottle (weighed before and after delivery) or from a pipette. Do not pipette cyclohexane by mouth use a rubber bulb. The quantity normally required is 15 mL. If a pipette is used, record the ambient temperature. 

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