Gram-atom

A/i the dissociation or bond energy of hydrogen (it is also, by definition, twice the enthalpy of atomisation two gram atoms being produced). 

It is evident from the equation that the sodium is used in excess. Actually 61 5 g. of n-propyl bromide is 0 5 gram mol this will react with 0 5 gram atom or 11-5 g. of sodium, so that 100 per cent, excess was actually employed. The theoretical yield of n-hexane will be 0-25 gram mol or 21-5 g., since 2 mols of n-propyl bromide give 1 mol of n-hexane. The actual yield was 18 g., hence the percentage yield is (18/21-5) X 100 = 84 per cent. 

To decide which component should be employed for the calculation of the yield of ethyl iodide, the weights of the reactants are first divided by the appropriate atomic or molecular weight in order to obtain the number of gram atoms or gram mols actually used. The equation shows that the alcohol and iodine react in the ratio of 5 5 or 1 1. Inspection of the results clearly shows that the alcohol is present in about 20 per... 

Place 204 g. (249-5 ml.) (2 gram mols) of dry n-hexyl alcohol in a 350 ml. Claisen flask with fractionating side arm. Introduce 5-75 g. (0-25 gram atoms) of clean sodium in small pieces and warm under reflux (as in Fig. Ill, 58, 1 but with dropping funnel omitted ) until all the sodium has reacted (ca. 2 hours). Introduce 39 g. (20 ml.) (0-25 gram... 

Corrosion Rate by CBD Somewhat similarly to the Tafel extrapolation method, the corrosion rate is found by intersecting the extrapolation of the linear poi tion of the second cathodic curve with the equihbrium stable corrosion potential. The intersection corrosion current is converted to a corrosion rate (mils penetration per year [mpy], 0.001 in/y) by use of a conversion factor (based upon Faraday s law, the electrochemical equivalent of the metal, its valence and gram atomic weight). For 13 alloys, this conversion factor ranges from 0.42 for nickel to 0.67 for Hastelloy B or C. For a qmck determination, 0.5 is used for most Fe, Cr, Ni, Mo, and Co alloy studies. Generally, the accuracy of the corrosion rate calculation is dependent upon the degree of linearity of the second cathodic curve when it is less than... 

If samples of two metals widr polished faces are placed in contact then it is clear that atomic transport must occur in both directions until finally an alloy can be formed which has a composition showing die relative numbers of gram-atoms in each section. It is vety unlikely that the diffusion coefficients, of A in B and of B in A, will be equal. Therefore there will be formation of an increasingly substantial vacancy concentration in the metal in which diffusion occurs more rapidly. In fact, if chemically inert marker wires were placed at the original interface, they would be found to move progressively in the direction of slowest diffusion widr a parabolic relationship between the displacement distance and time. 

An important element that must be recovered from zinc is cadmium, which is separated by distillation. The alloys of zinc with cadmium are regular solutions with a heat of mixing of 8300 Xcd fzn J gram-atom and the vapour pressures of the elements close to the boiling point of zinc (1180K) are... 

In a 3-I. three-necked, round-bottomed flask fitted with a mechanical stirrer, reflux condenser, and separatory funnel is placed 400 cc. of absolute alcohol (Note i). Through the condenser tube is added slowly, 23 g. (i gram atom) of dean sodium cut into thin slices. The completion of the reaction is hastened by heating the flask on a steam bath. When the sodium has dissolved completely, 143 g. (i.i moles) of ethyl acetoacetate is introduced slowly. Alter starting the mechanical stirrer, 123 g. (i mole) of ethyl chloroacetate (Note 2) is added slowly over a period of an hour, and the reaction mixture is refluxed for five to six hours. At this point the reaction mixture should no longer give an alkaline reaction with moist litmus. 

A. Ethyl Sodium Phthalimidoinalonate.—To a solution of 9.2 g. (0.4 gram atom) of sodium in 300 cc. of absolute alcohol at 60° is added, with efficient stirring, 126 g. (0.41 mole) of ethyl phthalimidomalonate (Org. Syn. Coll. Vol. i, 266). The mixture is rapidly chilled to 0° and the crystalline product filtered at once by suction and washed successively with two 200-cc. portions of absolute alcohol and two 200-cc. portions of ether. After first drying in a vacuum desiccator and then heating for eight hours imder 15 mm. pressure in a flask suspended in an oil bath at 145-155° (Note i), it weighs 108-III g. (82-85 per cent of the theoretical amount). 

A. Ester condensation. A suspension of 9.40 g. (0.41 gram atom) of powdered sodium in 100 ml. of absolute ether is placed in a 1-1. three-necked flask (Note 1) fitted with a reflux condenser, dropping funnel, and a calcium chloride tube. A solution of 23.8 ml. (0.41 mole) of absolute alcohol (Note 2) in 50 ml. of abso-... 

In a i-l. round-bottomed flask fitted with a reflux condenser protected by a calcium chloride tube 46 g. (2 gram atoms) of sodium is dissolved in 600 cc. of absolute alcohol (Note i). About one hour is required for the addition of the sodium, and another hour for its complete solution. Toward the end of the reaction the flask may be heated with a small smoky flame. While the sodium is being dissolved, the following materials are weighed in dry, stoppered containers 58 g. (r mole) of dry acetone (Note 2), 150 g. (1.03 moles) of freshly distilled ethyl oxalate (Org. Syn. Coll. Vol. i, 256), and 160 g. (i.i moles) of ethyl oxalate. 

In a i-l. round-bottomed, three-necked flask fitted with an efficient reflux condenser, liquid-sealed stirrer, and dropping funnel is placed t3 g. (0.53 gram atom) of magnesium turnings. A few cubic centimeters of a solution of 60 g. (41.4 cc., 0.55 mole) of pure ethyl bromide in 50 cc. of absolute ether is added and the stirrer started (Note i). When the bromide begins to react 200 cc. of absolute ether is added, and then the balance of the bromide solution is run in as fast as the refluxing permits (about one-half hour). After allowing fifteen minutes for the completion of the reaction, a solution of 40 g. (0.42 mole) of 2,4-dimethyl-pyrrole (Org. Syn. 15, 20) in 100 cc. of absolute ether is added in the course of twenty minutes (Note 2) and the mixture is refluxed for one-half hour on the steam bath. 

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