Closed tube test

In the closed tube test, a powdered mineral sample is placed at the bottom of a glass test tube and heated. The following characteristics must be reported ... 

Table 12.9. Mineral changes during the closed tube test...

Add 1.0 ml of Soln. F to the above pellet and heat the mixture to 90 °C for 1 h. It is recommended to close the test tubes with a glass ball to avoid dryness. 

Mix 2.0 ml of the sample solution after digestion or sample in Soln. A with Soln. E and E. Close the test tubes and incubate in the dark at 37 °C for 1.5-2 h. After that, read samples, blank, and standards at 750 nm. 

Close the test tube under the water with your thumb, extract it from the bath, wrap it in a towel, bring it up to the flame of a burner and, after opening the test tube, light the gas mixture. What happens ... 

Copper Sulphate Pentahydrate. Calculate what amount of copper sulphate crystallohydrate (blue vitriol) has to be taken for 10 ml of water to prepare a solution saturated at60°C (see Appendix 1, Table 1). Bring the solution obtained at the indicated temperature almost up to boiling and rapidly filter it through a fluted filter on a funnel for hot filtration (the funnel must be hot). Close the test tube with the filtrate with a piece of cotton wool. If crystals have formed in the filtrate, dissolve them by careful heating. Cool the solution and introduce a minute crystal of the initial salt into it. What is observed Does the temperature of the solution change ... 

Preparation of Anhydrous Dioxovanadium Nitrate (VO2NO3). Prepare 7-10 ml of liquid nitrogen(IV) oxide (see p. 141). Mix the nitrogen(IV) oxide with 5-7 cm of dry acetonitrile in a test tube (see Fig. 92a). Add 0.3-0.5 g of metallic vanadium preliminarily crushed in a porcelain mortar to this mixture. Close the test tube with a stopper provided with a calcium chloride tube containing phosphoric anhydride. 

Tetranitroanili nobutanol nitrate is a powerful expl(Bal Mortar Test 117% TNT). When heated above its mp it deflagrated at 205— 10° with a brilliant puff without deton, when heated to 216° it ignited in 5 secs. Its Sensitivity to Impact is comparable to that of retry I(Ref 6). Fairly stable in storage and when heated to 100° when heated in a closed tube at 135° for 30 mins, it exploded. Loss of wt in the 75° International Test 0.1% Hygroscopicity Test at 90% RH and 25° gain in wt 0.06% and at 100% RH 0.19% (Refs 2 3). Its Qv 1250.6 keal/mol and... 

Add 10 mL of the basic solution to 1 mL of the ether extract in a screw-cap test tube. Close the test tube with a Teflon-rubber septum cap. 

Small quantities of selenium in solution may be detected by the test described by Meunier,1 which is similar to Marsh s test for arsenic. If there is a relatively large amount of selenium present it is readily detected by its red colour, but if the amount of the element be small the deposit closely resembles that of arsenic, and in this case the following process may be adopted to detect the selenium. A current of hydrogen sulphide is passed into the hot solution containing a little sulphurous acid. The precipitate of finely divided sulphur carries down with it any selenium present and arsenic as arsenious sulphide, and it is clotted by stirring. In the presence of selenium the clots are brown they may be dried and the sulphur and selenium separated by careful sublimation in a closed tube. 

Discussion on burning rates of rocket double-base proplnts and the possible effects of changes in NG and total volatile content on the burning of jet propulsion tube proplnts) 2)A. Strasser, PATR 1235(1943)(Burning rates detd by closed bomb tests of 3/8 x 1/16" stick double-base proplnts of various compns) 3)A.Strasser, PATR 1474(1944XBuming characteristics of 3/8 stick rocket proplnts) 4)H.S.Seifert et al, AmJourPhysics 15, 122(1947)(Liquid proplnts) 5)G.J. Mueller,... 

Hypochlorites, (a) To 10 cc. of freshly prepared chlorine water, which has a distinct yellow color, add 6 N NaOH until the yellow color has disappeared. Close the test tube and shake thoroughly, and then note that the odor of chlorine has also disappeared. 

The entire procedure is performed in plastic (polystyrene) tubes and carried out at room temperature. Blood is drawn from healthy adult volunteers, who had not received medication for the last 2 weeks. 9 ml venous blood are anti-coagulated with 1 ml of sodium citrate and kept in a closed tube at room temperature for 30-60 min until the start of the test. 

For the aggregation studies, 10 pi test substance or vehicle (control) are added to 480 pi citrated blood. Samples in closed tubes are pre-incubated for 5 min in a 37 °C water shaker bath at 75 strokes/min. Ten pi... 

In a test tube, an organic substance such as sugar is mixed with the same amount of copper (ll) oxide, CuO. After closing the test tube with a stopper, and passing a delivery tube into another test tube containing lime water, Ca(OH)2, the mixture is heated. 

Preparation of Hydrofluoric Acid. Put 5 g of fluorite and 1 g of gypsum into a Teflon (polytetrafluoroethylene), lead, or copper test tube (why is gypsum added ). Pour 5 ml of a 96% sulphuric acid solution over the mixture, tightly close the test tube with a rubber stopper provided with a Teflon, lead, or copper gas-discharge tube. Lower the end of this tube into a Teflon, lead, copper, or paraffin-coated glass beaker containing 10 ml of water so that it only slightly touches the surface of the water (why ). Put an asbestos sheet between the beaker and the Teflon test tube. To speed up the reaction, it is recommended to immerse the Teflon test tube into a beaker with hot water. Why must the test tube not be heated directly by the flame of a burner ... 

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