Pyrex beakers

Method 1. From ammonium chloroplatinate. Place 3 0 g. of ammonium chloroplatinate and 30 g. of A.R. sodium nitrate (1) in Pyrex beaker or porcelain casserole and heat gently at first until the rapid evolution of gas slackens, and then more strongly until a temperature of about 300° is reached. This operation occupies about 15 minutes, and there is no spattering. Maintain the fluid mass at 500-530° for 30 minutes, and allow the mixture to cool. Treat the sohd mass with 50 ml. of water. The brown precipitate of platinum oxide (PtOj.HjO) settles to the bottom. Wash it once or twice by decantation, filter througha hardened filter paper on a Gooch crucible, and wash on the filter until practically free from nitrates. Stop the washing process immediately the precipitate tends to become colloidal (2) traces of sodium nitrate do not affect the efficiency of the catalyst. Dry the oxide in a desiccator, and weigh out portions of the dried material as required. 

Place 50 g. of o-chloronitrobenzene and 75 g. of clean dry sand in a 250 ml. flask equipped with a mechanical stirrer. Heat the mixture in an oil or fusible metal bath to 215-225° and add, during 40 minutes, 50 g. of copper bronze or, better, of activated copper bronze (Section 11,50, 4) (1), Maintain the temperature at 215-225° for a further 90 minutes and stir continuously. Pour the hot mixture into a Pyrex beaker containing 125 g. of sand and stir until small lumps are formed if the reaction mixture is allowed to cool in the flask, it will set to a hard mass, which can only be removed by breaking the flask. Break up the small lumps by powdering in a mortar, and boil them for 10 minutes with two 400 ml. 

To obtain catalyst of maximum and reproducible activity, it is recommended that the fusion be conducted in a Pyrex beaker or casserole resting in a cavity of a copper block heated with a burner and provided with a thermometer well. Adequate temperature control is thus possible. Short, J. Soc. Chem. Ind. 55, 14T (1936). 

Ammonium chloroplatinate often can be used to advantage in place of chloroplatim c acid in the preparation of Adams catalyst. A mixture of 3 g. of ammonium chloroplatinate and 30 g. of sodium nitrate in a casserole or Pyrex beaker is heated gently at first until the rapid evolution of gas slackens and then more strongly until a temperature of 500° is reached. This operation requires about fifteen minutes and there is no spattering. The temperature is held at 500-520° for one-half hour and the mixture is then allowed to cool. The platinum oxide catalyst, collected in the usual way by extracting the soluble salts with water, weighs 1.5 g. and it is comparable in appearance and in activity to the material prepared from chloroplatinic acid. 

Titration assembly. The electrode system consists of a mercury electrode and a saturated calomel [or, in some cases, a mercury-mercury(I) sulphate] reference electrode, both supported in a 250 mL Pyrex beaker. Provision is made for magnetic stirring and the potential is followed by means of an electronic millivoltmeter or an auto-titrator. 

Procedure. Pipette 25.0 mL of the thiosulphate solution into the titration cell e.g. a 150mL Pyrex beaker. Insert two similar platinum wire or foil electrodes into the cell and connect to the apparatus of Fig. 16.17. Apply 0.10 volt across the electrodes. Adjust the range of the micro-ammeter to obtain full-scale deflection for a current of 10-25 milliamperes. Stir the solution with a magnetic stirrer. Add the iodine solution from a 5 mL semimicro burette slowly in the usual manner and read the current (galvanometer deflection) after each addition of the titrant. When the current begins to increase, stop the addition then add the titrant by small increments of 0.05 or 0.10 mL. Plot the titration graph, evaluate the end point, and calculate the concentration of the thiosulphate solution. It will be found that the current is fairly constant until the end point is approached and increases rapidly beyond. 

Method 2. From chloroplatinic acid. Dissolve 3 6 g. of the purest commercial chloroplatinic acid (3) in 10 ml. of water contained in a 260 ml. Pyrex beaker or porcelain casserole, and add 36 g. of A.R. sodium nitrate (1). Evaporate the mixture to dryness by heating gently over a Bunsen flame whilst stirring with a glass rod. Then raise the temperature... 

Place about 120 cc. of pure water in a Pyrex beaker of 300 to 500 cc. capacity and heat to boiling. While warming the water, add 2.5 cc. of a solution of gold chloride (6 g. crystallized HAuC14-3H20 per liter) and 3 cc. of a solution of pure potassium carbonate (0.2... 

In a typical procedure, approximately 30 g of uranium metal turnings are cut into small strips of approximately 0.5-1.5 in. in length using steel scissors and transferred to a 250-mL Pyrex beaker inside a well-ventilated fume hood. Concentrated nitric acid (16 M) is added to just cover the uranium turnings. The turnings are swirled with the acid approximately 1 min. 

The enthalpy of combustion of 1.00 mol CH3OH(l) is —726 kj. (a) Write a balanced equation for the combustion of 1 mol CH3OH(l). (b) What mass of methanol must be burned to heat 209 g of water in a 50.0-g Pyrex beaker from 20°C to 100°C For additional information, see Table 6.1. (c) Using the enthalpy of combustion and the enthalpies of formation of the products of the combustion reaction, calculate the enthalpy of formation of methanol. 

Samples of 1 (200 mg) were sealed in evacuated Pyrex ampoules (inner diameter 4 mm) and immersed in a 500-mL Pyrex beaker filled with ice and water in such a way that no ice blocked the laser beam. The beam of an excimer laser (Lambda Physics, EMC 201 XeCl 17 ns pulses 50 Hz repetition rate 3 h X = 308 nm) was positioned vertically using two dielectric mirrors and focused to the desired intensity by a quartz-lens with a focal length of 20 cm. For low intensity irradiations, the ampoules were placed in front of a mercury arc at a distance of 5 cm. The product ratio depended on the light intensity. The compounds 1, 2, 3 and 4 were separated by gas chromatography or HPLC on RP18 and spectroscopically characterized after 93-97% conversion to 3 and 4. 

Fig. 6. Beaker type celL A Pyrex beaker B Alundum membrane C Side-arm contact to the mercury pool consisting of a piece of glass tubing through which is sealed a piece of platinum D Thermometer E Reference electrode F Cathode lead wire G Nitrogen inlet and outlet tubes (for removal of peroxides from anode compartment) H Glass or teflon covered magnetic bar / Magnetic stirrer. (Taken from Ref., p. 34)...

Sample Preparation. Petroleum oils were extracted with acidified methanol, according to a procedure previously described (14). Samples of sea water containing soluble petroleum oil fractions were prepared by gently spreading an oil layer (1-2 mm thick) on fresh sea water contained in a 4 liter Pyrex beaker. 

Samples from the field are redeposited on membrane filters by filtering a suspension of ashed sample. To ash field samples, the filter is placed dust side down in a 50 ml pyrex beakers and placed in a low-temperature radio frequency asher. The asher used has two chambers and will accommodate eight beakers at one time. The oxygen flow is set at 15 see per minute. Samples are initially ashed for 15 minutes at a RF wattage of 100 watts to prevent the filter from curling due to high heat. The RF wattage is then increased to 250 watts and the sample is allowed to ash for an additional 30-45 minutes to eliminate any carbonaceous material. The ash is treated with one milliliter of hydrochloric acid to elimi-... 

Reagent grade potassium chloride is intimately mixed with reagent grade metal-(II) chloride and the mixture is heated in a 250-mL pyrex beaker, in air at 200-250° for 3 hours. Proportions of mixed salts and compositions of the different double chlorides appear in Table II. 

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