Platinum test wire

Test the water in the trough with red litmus paper. Push the paper to the bottom or to the place where it is certain that chemical action between water and sodium has taken place. Test, until the red litmus paper has undergone a decided change in color. Describe this final result. With another piece of red litmus paper test a solution made by dissolving a small piece of sodium hydroxide in a test tube half full of water. Is the result similar Dip the platinum test wire (see App. A, 14) into this solution and hold it in the Bunsen flame. Describe the result. Is the color of this flame and that noticed in ( r) the same ... 

Test another portion thus Moisten the platinum test wire (see App. A, 14) with water, dip the loop into the solid, and hold it in the Bunsen flame. Note the intense color. Clean the wire with hot water or sandpaper, and repeat with any compound known to contain sodium, or which you have made from sodium. (Compare Exp. 42 (< ).) What does this result prove qualitatively about the specific nature of the substance under examination Give the name of the substance. State the chemical changes which led to its forrfiation. 

Dip a clean, moist platinum test wire into the solid residue, and hold t in the Bunsen flame. If calcium is present, the flame will be colored a yellowish red. 

Experiment 103. — Make a small loop on the end of the platinum test wire (see App. A, 14), moisten it, and dip it into powdered borax. Heat it in the flame, rotating it slowly at first the borax swells, but finally shrinks to a small, transparent bead. If the bead is too small, add more borax and heat again. After use, the bead may be removed by dipping it, while hot, into water the sudden cooling shatters the bead, which may then be easily rubbed or scraped from the wire. 

A fuel cell is a device that converts chemical energy directly into electrical energy, and its operation can be explained using electrochemical concepts that are well understood. The simplest form was developed in 1839 by the talented British chemist William R. Grove, using a beaker, two test tubes, platinum coated wires, and a dilute acid. 

In these equations the electrostatic potential i might be thought to be the potential at the actual electrodes, the platinum on the left and the silver on the right. However, electrons are not the hypothetical test particles of physics, and the electrostatic potential difference at a junction between two metals is nnmeasurable. Wliat is measurable is the difference in the electrochemical potential p of the electron, which at equilibrium must be the same in any two wires that are in electrical contact. One assumes that the electrochemical potential can be written as the combination of two tenns, a chemical potential minus the electrical potential (- / because of the negative charge on the electron). Wlien two copper wires are connected to the two electrodes, the... 

If an appreciable amount of residue remains, note its colour. Add a few drops of water and test the solution (or suspension) with htmus or with Universal indicator paper. Then add a httle dilute hydrochloric acid and observe whether efiervesceiice occurs and the residue dissolves. Apply a flame test with a platinum wire on the hydrochloric acid solution to determine the metal present. (In rare cases, it may be necessary to subject a solution of the residue to the methods of qualitative inorganic analysis to identify the metal or metals present.) If the flame test indicates sodium, repeat the ignition of the substance on platinum foil. 

That oxidized surfaces appear to yield higher CHFs than clean metallic surfaces was also reported by Ivey and Morris (1965). They found little difference in the CHF for wires that are not prone to severe oxidation. Results of tests with 0.020-in. wires of platinum, Chromel, silver, stainless steel, and nickel yielded CHFs of 350,000 + 20% BTU/hr ft2 (1.1 X 106 + 20% W/m2). The scatter in the data for a given wire, as well as for different materials, was within the 20% band. 

When a platinum wire (which may have been hot) was dipped for a flame test into a sintered funnel containing the air-dried complex, detonation occurred. This may have been due to heat and/or friction on a compound containing both strongly oxidising and reducing radicals. Avoid dipping (catalytically active) platinum wire into bulk samples of materials of unknown potential. 

The flammability of solid substances is determined by burning rate tests [10,134,135]. From a mold, a pile of the substance under investigation is placed on a noncombustible, nonporous, and low heat-conducting base plate. One end of the pile is ignited by a hot gas flame or a hot platinum wire (temperatures above 1000°C). The burning rate is established and measured. 

A spirit burner. .., blow-pipe, one platinum crucible, one platinum sheet and 3-4 platinum wires, a test tube stand with 10-12 test tubes, several beakers and flasks, one porcelain dish and a pair of porcelain crucibles, several glass filter funnels in various sizes, a wash-bottle, several rods and watch glasses, one agate mortar, several iron spoons, a pair of steel or brass pincers, a filtration stand made of wood and one iron tripod stand. 

To clean the boat boil it in a test tube with dilute nitric acid, attach it to a platinum wire, and ignite it for a short time in the (non-luminous) Bunsen flame. Then set it to cool for about twenty seconds on a nickelled copper block. 

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