TY - JOUR
T1 - The dissociation constants of carbonic acid in seawater at salinities 5 to 45 and temperatures 0 to 45°C
AU - Roy, Rabindra N.
AU - Roy, Lakshimi N.
AU - Vogel, Kathleen M.
AU - Porter-Moore, C.
AU - Pearson, Tara
AU - Good, Catherine E.
AU - Millero, Frank J.
AU - Campbell, Douglas M.
N1 - Funding Information:
The ChemistryD epartmenatt Drury College acknowledgetsh e support of the Petroleum ResearchF und, administerebdy the American Chemical Society ACS-PRF No. 20409-BS-C. F.J. Millero and D.M. Campbella cknowledge the support of the Office of Naval Research, the oceanographics ection of the National ScienceF oundation,a nd the National Ocean and AtmospheriAc dministration.
PY - 1993/12
Y1 - 1993/12
N2 - The pK1* and pK2* for the dissociation of carbonic acid in seawater have been determined from 0 to 45°C and S = 5 to 45. The values of pK1* have been determined from emf measurements for the cell:Pt](1 - X)H2 + XCO2|NaHCO3, CO2 in synthetic seawater|AgC1; Ag where X is the mole fraction of CO2 in the gas. The values of pK2* have been determined from emf measurements on the cell: Pt, H2(g, 1 atm)|Na2CO3, NaHCO3 in synthethic seawater|AgC1; Ag The results have been fitted to the equations: lnK*1 = 2.83655 - 2307.1266/T - 1.5529413 lnT + (-0.20760841 - 4.0484/T)S0.5 + 0.08468345S - 0.00654208S1 InK*2 = -9.226508 - 3351.6106/T- 0.2005743 lnT + (-0.106901773 - 23.9722/T)S0.5 + 0.1130822S - 0.00846934S1.5 where T is the temperature in K, S is the salinity, and the standard deviations of the fits are σ = 0.0048 in lnK1* and σ = 0.0070 in lnK2*. Our new results are in good agreement at S = 35 (±0.002 in pK1* and ±0.005 in pK2*) from 0 to 45°C with the earlier results of Goyet and Poisson (1989). Since our measurements are more precise than the earlier measurements due to the use of the Pt, H2|AgCl, Ag electrode system, we feel that our equations should be used to calculate the components of the carbonate system in seawater.
AB - The pK1* and pK2* for the dissociation of carbonic acid in seawater have been determined from 0 to 45°C and S = 5 to 45. The values of pK1* have been determined from emf measurements for the cell:Pt](1 - X)H2 + XCO2|NaHCO3, CO2 in synthetic seawater|AgC1; Ag where X is the mole fraction of CO2 in the gas. The values of pK2* have been determined from emf measurements on the cell: Pt, H2(g, 1 atm)|Na2CO3, NaHCO3 in synthethic seawater|AgC1; Ag The results have been fitted to the equations: lnK*1 = 2.83655 - 2307.1266/T - 1.5529413 lnT + (-0.20760841 - 4.0484/T)S0.5 + 0.08468345S - 0.00654208S1 InK*2 = -9.226508 - 3351.6106/T- 0.2005743 lnT + (-0.106901773 - 23.9722/T)S0.5 + 0.1130822S - 0.00846934S1.5 where T is the temperature in K, S is the salinity, and the standard deviations of the fits are σ = 0.0048 in lnK1* and σ = 0.0070 in lnK2*. Our new results are in good agreement at S = 35 (±0.002 in pK1* and ±0.005 in pK2*) from 0 to 45°C with the earlier results of Goyet and Poisson (1989). Since our measurements are more precise than the earlier measurements due to the use of the Pt, H2|AgCl, Ag electrode system, we feel that our equations should be used to calculate the components of the carbonate system in seawater.
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U2 - 10.1016/0304-4203(93)90207-5
DO - 10.1016/0304-4203(93)90207-5
M3 - Article
AN - SCOPUS:0027840604
SN - 0304-4203
VL - 44
SP - 249
EP - 267
JO - Marine Chemistry
JF - Marine Chemistry
IS - 2-4
ER -