EVERETT DOUGLAS
2608
Solubilities of Argon and Nitrogen in Sea Water
by Everett Douglas Scripps Institution of Oceanography, La Jolla, California1f2 (Received February 3, 1965)
The solubility coefficients of argon and nitrogen have been determined in sea water a t three chlorinities from 2 to 30" with an estimated accuracy of &0.25% for argon and &0.5% for nitrogen. These values have been compared with those of previous workers showing the argon values of Konig to be inconsistent with the present values while those of Rakestraw and Emmel exhibit good agreement a t the higher chlorinities. The nitrogen values of Rakestraw and Emmel are higher than those reported here.
Introduction With the recent interest in the inert gases in sea w ~ t e r , ~it- ~has become necessary t o establish accurately their saturation values in sea water. Using a microgasometric method, the solubility coefficients of nitrogen and argon have been determined. The values of Rakestraw and EmmeP for nitrogen have generally been accepted as the standards over those of FOX,^ his values being higher than those of Rakestraw and Emmel. Remarkably good results for argon were achieved by Rakestraw and Emmel using atmospheric ~~~~
C1 o/oo = 15.376
--
Temperature, 'C.
15.0
6.46
10.00
14.80
19.99
0.04246 0.04246 0.04252 0.04248
0.03780 0.03797 0.03775 0.03784
0.03493 0.03487 0.03499 0.03493
0.03180 0.03162 0.03170 0.03171
0.02891 0.02894 0.02889 0.02891
C1 o/oo
=
25.01
29.83
0.02668 0.02487 0.02666 0.02473 0.02662 0.02483 0.02665 0.02481
18.604
Temperature, 'C.-----2.17
Av.
0.04019 0.04020 0.04023 0,04021
6.80
10.25
0.03601 0.03342 0.03626 0.03346 0.03619 0 . 0 3 3 4 3 0.03615 0 . 0 3 3 4 4
14.71
20.46
25.27
C1 o/oo = 20.985
Av.
5.92
0.03919 0.03910 0.03906 0,03912
0.03583 0.03574 0.03582 0.03580
10.15
15.05
0.03267 0 . 0 2 9 7 0 0.03273 0.02963 0.03266 0 . 0 2 9 6 8 0.03269 0.02967
The Journal of Physical Chemistry
29.72
0.03066 0.02770 0.02567 0.02413 0.03065 0.02772 0.02567 0.02412 0.03060 0.02769 0.02563 0.02405 0.03064 0.02770 0.02566 0.02410
-- Temperature, O-C-. 2.10
Experimental The method employed has been described earlier.lo The absorption apparatus has been enlarged to accommodate approximately 8 ml. of water in order to maintain the same level of accuracy as obtained with distilled water. l 1 Gas-free sea water, millipore filtered and stored a t 4", was obtained by vacuum extracting it over mercury. 12, l 3 The determination of chlorinity was
~
Table I : Experimental Solubility Coefficients of Argon
Av.
air while the solubility of the pure gas was first investigated by Konigs in 1963.
20.50
24.88
29.99
0.02702 0 . 0 2 5 1 2 0.02342 0.02701 0.02514 0.02344 0.02702 0 . 0 2 5 1 7 0.02343 0.02702 0.02514 0 . 0 2 3 4 3
(1) Contribution from the Scripps Institution of Oceanography, University o f California, San Diego, Calif. (2) This investigation was supported by Public Health Service Research Grant No. GM 10521 from the National Institutes of Health. (3) R. Bieri, M. Koide, and E. D. Goldberg, Science, 146, 1035 (1964). (4) B. B. Benson and P. D. M. Parker, Deepsea Res., 7, 237 (1961). (5) T. Enns, P. F. Scholander, and E. D. Bradstreet, J . Phys. Chem., 69, 389 (1965). (6) E. Mazer, G. I. Wasserburg, and H. Craig, Deep-sea Res., 11, 929 (1964). (7) N. W. Rakestraw and V. M. Emmel, J . Phys. Chem., 42, 1211 (1938). (8) C. J. J. Fox, Trans. Faraday Soc., 5 , 68 (1909). (9) H. Von Konig, 2. Naturforsch., 18a, 363 (1963). (10) E. Douglas, J . Phys. Chem., 68, 169 (1964). (11) Due to an oxidation occurring using pure oxygen with sea water over mercury, the determination of 02 values could not be undertaken. (12) As this does not remove all of the COz, a possible maximum uncertainty of 0.2% for argon and 0.4% for nitrogen could be introduced if the COZin the sea water reaches equilibrium with the pure gas during equilibration. Analysis of the gas with a Scholander 0.5-cc. gas analyser,ls however, showed the COz concentration to be less than 0.03%. (13) P. F. Scholander, J . Biol. Chem., 167, 235 (1947).
SOLUBILITIES OF ARGONAND NITROGEN IN SEAWATER
2609
~~
Table I1 : Argon Solubility in Sea Water"
Table IV : Nitrogen Solubility in Sea Water a-Nitrogen Chlorinity
or-Argon
Temp., oc.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
--
Temp., "C.
-Chlorinity
15
16
17
18
19
20
21
0.04443 0.04326 0.04212 0.04117 0.04022 0.03931 0.03840 0.03752 0.03665 0.03581 0.03504 0.03430 0.03362 0.03295 0.03230 0.03169 0.03112 0.03059 0.03001 0.02949 0.02900 0.02851 0.02806 0.02760 0.02717 0.02675 0.02636 0.02597 0.02560 0.02521 0.02485
0.04387 0.04274 0.04164 0.04069 0.03974 0.03885 0.03795 0.03709 0.03624 0.03541 0.03465 0.03393 0.03325 0.03259 0.03195 0.03135 0.03079 0.03025 0.02970 0.02919 0.02870 0.02822 0.02776 0.02732 0.02689 0.02648 0.02608 0.02570 0.02534 0.02496 0.02461
0.04331 0.04222 0.04115 0.04021 0.03928 0.03840 0.03751 0.03666 0.03582 0.03502 0.03427 0.03355 0.03288 0.03223 0.03160 0.03102 0.03046 0.02991 0.02938 0.02889 0.02840 0.02793 0.02748 0,02703 0.02661 0,02620 0.02582 0.02544 0.02509 0.02472 0.02437
0.04276 0.04170 0.04066 0.03974 0.03882 0.03794 0.03707 0.03623 0.03540 0.03462 0.03389 0.03318 0.03252 0.03187 0.03126 0.03068 0.03013 0.02958 0.02908 0.02858 0.02811 0.02763 0.02718 0.02674 0.02633 0.02593 0.02554 0.02518 0.02483 0.02447 0.02414
0.04220 0.04118 0.04017 0.03926 0.03836 0.03748 0.03663 0.03580 0.03500 0.03423 0.03350 0.03281 0.03215 0.03152 0.03092 0.03035 0.02980 0.02924 0.02876 0.02828 0.02782 0.02734 0.02690 0.02645 0.02605 0.02566 0.02527 0.02492 0.02458 0.02422 0.02390
0.04165 0.04066 0.03968 0.03878 0.03789 0.03703 0.03618 0.03536 0.03458 0.03383 0.03312 0.03243 0.03178 0.03116 0.03058 0.03002 0.02948 0.02890 0.02846 0.02799 0.02751 0.02706 0.02661 0.02617 0.02576 0.02538 0.02500 0.02466 0.02432 0.02398 0.02366
0.04110 0.04014 0.03920 0.03830 0.03742 0.03657 0.03574 0.03494 0.03416 0.03344 0.03273 0.03206 0.03141 0.03080 0.03023 0.02969 0.02915 0.02856 0.02815 0.02768 0.02722 0.02677 0.02632 0.02589 0.02549 0.02511 0.02474 0.02440 0.02407 0.02373 0.02343
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
18 19 20 21 22 23 24 25 26 27 28 29 30
I
15 0.01931 0.01886 0.01845 0.01804 0.01766 0.01727 0.01691 0.01656 0.01622 0.01587 0.01554 0.01523 0.01496 0.01469 0.01440 0.01419 0.01396 0.01373 0.01351 0.01329 0.01309 0.01288 0.01268 0.01249 0.01231 0.01214 0.01199 0.01185 0.01173 0.01159 0.01146
16 0.01904 0.01860 0.01820 0.01780 0.01742 0.01705 0.01669 0.01635 0.01602 0.01568 0.01536 0.01506 0.01478 0.01452 0.01424 0.01403 0.01380 0.01357 0.01335 0.01314 0.01293 0.01273 0.01254 0.01235 0.01218 0.01202 0.01187 0.01173 0.01160 0.01147 0.01134
18 0.01850 0.01809 0.01770 0.01732 0.01696 0.01661 0.01627 0.01595 0.01562 0.01530 0.01500 0.01471 0.01444 0.01418 0.01392 0.01370 0.01346 0.01325 0.01303 0.01282 0.01263 0.01244 0.01226 0.01208 0.01192 0.01176 0.01162 0.01148 0.01136 0.01124 0.01111
17 0.01877 0.01835 0.01795 0.01756 0.01719 0.01683 0.01648 0.01615 0.01582 0.01549 0.01518 0.01488 0.01461 0.01435 0.01408 0.01386 0.01363 0.01341 0.01319 0.01298 0.01278 0.01259 0.01240 0.01222 0.01205 0.01189 0.01174 0.01160 0.01148 0.01135 0.01123
a It should be noted t h a t chlorinity is expressed in terms of grams of chlorine per kilogram of sea water, while a is given as volume of gas (STPD) absorbed by a unit volume of water when t h e pressure of the gas is 760 mm.
W -I
s
Table 111: Experimental Solubility Coefficients of Nitrogen
20 0.01797 0.01758 0.01720 0.01684 0.01650 0.01616 0.01584 0.01554 0.01522 0.01492 0.01463 0.01436 0.01409 0.01384 0.01360 0.01338 0.01312 0.01293 0.01271 0.01250 0.01232 0.01214 0.01197 0.01180 0.01165 0.01151 0.01137 0.01124 0.01112 0.01101 0.01088
21 0.01770 0.01732 0.01696 0.01660 0.01626 0.01594 0.01563 0.01533 0.01502 0.01473 0.01445 0.01418 0.01392 0.01367 0.01344 0.01321 0.01295 0.01277 0.01255 0.01235 0.01217 0.01199 0.01183 0.01166 0.01152 0,01138 0.01125 0,01112 0.01100 0.01089 0.01077
15 %o RAKESTRAW a EMMEL
v)
3
7
19 0.01824 0.01783 0.01745 0.01708 0.01673 0.01639 0.01606 0.01574 0.01542 0.01511 0.01481 0.01453 0.01426 0.01401 0.01376 0.01354 0.01329 0.01309 0.01287 0.01266 0.01248 0.01229 0.01211 0.01194 0.01179 0.01164 0.01150 0.01136 0.01124 0.01112 0.01100
I -
I 8 % 0 R 8 a E,
6 0
4
C1 a/oo = 15.376 Temperature, C ' .1.50
Av.
6.46
10.00
14.81
19.99
0.01857 0.01661 0.01544 0.01416 0.01299 0.01858 0.01667 0.01550 0.01422 0.01303 0.01852 0.01670 0.01551 0.01417 0.01304 0.01856 0.01666 0.01546 0.01418 0.01302
7
25.08
29.83
0.01209 0.01210 0.01203 0.01207
0.01137 0.01144 0.011.39 0.01140
C1 o / o o = 18.604 2.17
Av.
0.01746 0.01748 0.01746 0.01747
6.80
10.25
0.01588 0.01485 0.01589 0.01476 0.01592 0.01485 0.01590 0.01482
14.51 0.01373 0.01367 0.01370 0.01370
"-.PI ,
LL
Temperature, OC-. 19.41 0.01264 0.01269 0.01268 0.01267
7
25.27
29.72
0.01161 0.01168 0.01165 0.01165
0,01109 0,01111 0.01107 0.01109
24.88
29.99
I 9 vo0K ~ N I G
W 0
,
,
ARGON
z
w
LL
21 % O R, a E,
C1 o/oo = 20.985 Temperature, OC.
Av.
2.10
5 92
10.15
15.05
0.01689 0.01692 0.01698 0.01693
0.01566 0.01563 0.01567 0.01565
0.01442 0.01436 0.01442 0.01440
0.01319 0.01320 0.01320 0.01320
19.41 0.01227 0.01222 0.01231 0.01227
0.01140 0.01076 0.01139 0.01078 0.01139 0.01071 0.01139 0.01075
0
5
IO
I5
20 25
3OoC
MI TROGEN Figure 1. Values of Rakestraw and Emmel (top) were recalculated t o 1 atm. of pure argon from atmospheric air values. Values of Konig were obtained using pure argon.
Volume 69, Number 8
August 1966
2610
accomplished by a scaled-down version of the Mohr method. Approximately 1 ml. of sea water with dichromate indicator added plus 2 ml. of double-distilled water was titrated with a silver nitrate solution by means of a syringe microburet14 for precise delivery. These were all titrated against Copenhagen water. Accuracy a t this level was It 0.05"/,,. The purity of the nitrogen and argon used was determined on a mass spectrometer, showing the nitrogen to contain 0.04% oxygen and less than 0.03% argon. The argon contained less than 0.1% nitrogen and less than 0.01% COz.
Results and Discussion Argon. The results obtained for argon in three different chlorinities are shown in Table I. Smooth curves were fitted on these points from which the avalues from 0 to 30" were taken. From these values the linear relations between solubility and chlorinity were plotted and the solubility values from 0 to 30" in
The Journal of Physical Chemistry
EVERETT DOUGLAS
chlorinities ranging from 15 to 21°/,, were obtained. These values are tabulated in Table 11. Figure 1 (top) illustrates the per cent difference of previous argon values from the present a t the indicated chlorinities. Nitrogen. The experimental results for nitrogen are given inTable IIIwith the interpolated values shown in Table IV. A comparison with Rakestraw and Emmel in Figure 1 (bottom) shows their values to be somewhat higher. Acknowledgments. The author wishes to acknowledge numerous helpful discussions with Dr. P. F. Scholander during the course of this work. The author also is indebted to Dr. G. V. Pickwell for some earlier chloride titrations and to J. A t . Wells and J. Wright for collection of the sea water. Thanks are due to Dr. Scholander and Dr. T. Enns for their critical readings of the manuscript. (14) Syringe Microburet Model No. SB2, Micro-Metric Instrument Co., Cleveland, Ohio.
