1662
JOURNAL OF CHEMICAL EDUCATION
JULY. 1930
Problem: A steel tank of 8 cu. ft. capacity i s fLlled with oxygen under a pressure of 100 lb. per sp. i n . and a temperature of 6S°F. - What is the weight of the oxygen i n the tunk neglecting dewietions from the gas laws? Firrt solution: 68°F.
=
20'C.
Pressure in atmospheres =
100 = 14.7
Volume gas S. T. P. in cubic feet
6.80
= 8
X
273
293
X
6.8
Volume gas in liten
= 50.6 = 50.6 X 28.32 (1 cu. ft. = 28.32 1.) = 1435
Weight O1 in grams
-
X 32 (22.4 1. OP = 32 8.) 22.4
=
2050
Weight O2in pounds
= 2050 X 2.20 = 4.51 lb.
1000
-
Answer
Second solution;
273 293
6.8 1
X - X - = 50.6 cu. ft.
Volume gas S.T.P.
= 8
Weight oxygen
= - X 32 (1 P.M.W. 02, 359 cu. ft. = 32 lb.)
359
= 4.51 Ib.
Answer
A comparison of the two solutions shows that the second solution making use of the idea of the pound-molecular-volume is superior from the standpoint of simplicity, freedom from the use of awkward conversion factors, and because i t involves fewer arithmetical operations. I n concluding, may I emphasize that the writer is not putting forth a brief for the retention of the f. p. s. systsm of units? He merely wishes t o call attention t o the fact that it is unscientific to slavishly rely on the use of the metric system of units in situations where the English units are in common use. In such cases, as a matter of fact, the use of the metric units is often a distinct handicap. This is especially true when working with problems which involve volumes of gases expressed in cubic feet. In such cases, the concept of the ounce-molecular-weight or of the poundmolecular-weight might advantageously be used.
Claude's Attempt to Utilize Energy of Gulf Stream. The French scientist, M . Georges Claude, developer of neon gas lights and important synthetic processes, is proceeding with an extensive investigation a t Matanga, Cuba, to utilize the potential heat energy of the Gulf Stream. The surface water there is said to be 40 degrees warmer than the water 2000 ft. below. Claude expects to develop a practical means of transferring this heat energy difference-potential and utilizing it. The preliminary plans involve dropping a pipe line to the bottom to hring up the cold water, taking off the power through use of the turbine engine which takes advantage of the flow of vapor l engineers beset free by the proximity of water a t two different temperatures. h lieve that his project probably indudes search for gases present in the water a t the ATTAcnC TODD.HABANA, via Ckcm. Age ocean bottom.-U. S. A. COMWERCIAL
