Malonic Acid and Malonate Mixture Data

(1a) Water Activities of Aqueous H2Malo + (NH4)2SO4 Mixtures (1:1 Mole Ratio)

   aW        mfs         m       osm      np        t        uncert.    ref.  weight
  1.000    0.0000      0.0000   1.00     bulk      22.0      0.003       a     1.0
  0.945    0.2254      1.2217   0.6426   bulk      22.0      0.003       a     1.0
  0.894    0.3422      2.1841   0.7119   bulk      22.0      0.003       a     1.0
  0.880    0.3724      2.4913   0.7121   bulk      22.0      0.003       a     1.0
  0.861    0.4010      2.8107   0.7389   bulk      22.0      0.003       a     1.0                
  0.831    0.4332      3.2089   0.8006   bulk      22.0      0.003       a     1.0                               
  0.3407   0.9700       -        -        1e       20-23     0.01        a      -                        
  0.3657   0.9627       -        -        1e       20-23     0.01        a      -                          
  0.3901   0.9621       -        -        1e       20-23     0.01        a      -                          
  0.4058   0.9549       -        -        1e       20-23     0.01        a      -                          
  0.4691   0.9491       -        -        1e       20-23     0.01        a      -                          
  0.4773   0.8724       -        -        1e       20-23     0.01        a      -                          
  0.4811   0.8590     25.578    0.3970    1e       20-23     0.01        a      -                          
  0.4846   0.8413     22.257    0.4517    1e       20-23     0.01        a      -                         
  0.5025   0.8259     19.917    0.4795    1e       20-23     0.01        a      -                         
  0.5244   0.8107     17.981    0.4982    1e       20-23     0.01        a      -                         
  0.5379   0.7982     16.607    0.5182    1e       20-23     0.01        a      -                         
  0.5631   0.7702     14.072    0.5664    1e       20-23     0.01        a      -                         
  0.5769   0.7562     13.023    0.5862    1e       20-23     0.01        a      -                         
  0.5867   0.7354     11.669    0.6342    1e       20-23     0.01        a      -                         
  0.6056   0.7086     10.210    0.6817    1e       20-23     0.01        a      -                         
  0.6310   0.6998      9.7872   0.6529    1e       20-23     0.01        a      -                         
  0.6456   0.6749      8.7160   0.6967    1e       20-23     0.01        a      -                         
  0.6560   0.6570      8.0420   0.7275    1e       20-23     0.01        a      -                         
  0.6782   0.6351      7.3074   0.7374    1e       20-23     0.01        a      -                         
  0.6958   0.6103      6.5752   0.7655    1e       20-23     0.01        a      -                         
  0.7188   0.5811      5.8242   0.7867    1e       20-23     0.01        a      -                         
  0.7358   0.5541      5.2173   0.8160    1e       20-23     0.01        a      -                          
  0.7518   0.5302      4.7383   0.8355    1e       20-23     0.01        a      -                          
  0.7641   0.5067      4.3126   0.8658    1e       20-23     0.01        a      -                          
  0.7772   0.4906      4.0436   0.8650    1e       20-23     0.01        a      -                          
  0.7956   0.4656      3.6580   0.8675    1e       20-23     0.01        a      -                                                 
  0.8000   0.4613      3.5953   0.8613    1e       20-23     0.01        a      -                                                 
  0.3716   0.9030     39.085     -        2e       20-23     0.01        a      -                                                                        
  0.3719   0.8984     37.125     -        2e       20-23     0.01        a      -                                                                        
  0.4207   0.8898     33.901     -        2e       20-23     0.01        a      -                                                                                        
  0.4590   0.8865     32.793     -        2e       20-23     0.01        a      -                                                                                                               
  0.4762   0.8225     19.455    0.5292    2e       20-23     0.01        a      -                                                               
  0.5281   0.7730     14.297    0.6197    2e       20-23     0.01        a      -                                                              
  0.5479   0.7513     12.683    0.6583    2e       20-23     0.01        a      -                                                              
  0.5675   0.7397     11.931    0.6589    2e       20-23     0.01        a      -                                                              
  0.5849   0.7217     10.888    0.6836    2e       20-23     0.01        a      -                                                              
  0.5915   0.7095     10.254    0.7106    2e       20-23     0.01        a      -                                                              
  0.6243   0.6846      9.1132   0.7174    2e       20-23     0.01        a      -                                                              
  0.6451   0.6625      8.2415   0.7381    2e       20-23     0.01        a      -                                                              
  0.6607   0.6382      7.4060   0.7766    2e       20-23     0.01        a      -                                                              
  0.6822   0.6253      7.0065   0.7575    2e       20-23     0.01        a      -                                                              
  0.6976   0.6119      6.6196   0.7549    2e       20-23     0.01        a      -                                                              
  0.7171   0.5839      5.8916   0.7833    2e       20-23     0.01        a      -                                                              
  0.7298   0.5670      5.4978   0.7951    2e       20-23     0.01        a      -                                                              
  0.7460   0.5473      5.0759   0.8011    2e       20-23     0.01        a      -                                                              
  0.7624   0.5245      4.6312   0.8129    2e       20-23     0.01        a      -                                                              
  0.7744   0.5052      4.2868   0.8277    2e       20-23     0.01        a      -                                                              
  0.7842   0.4858      3.9666   0.8505    2e       20-23     0.01        a      -                                                              
  0.7956   0.4731      3.7698   0.8417    2e       20-23     0.01        a      -                                                              
  0.8000   0.4685      3.7008   0.8367    2e       20-23     0.01        a      -                                                              
  0.1929   0.9424       -        -        2e       20-23     0.01        a      -                                                              
  0.0776   0.9999       -        -        2e       20-23     0.01        a      -                                                              
  0.2000   1.0000       -        -        1g       20-23     0.01        a      -                                                              
  0.2880   0.9900       -        -        1g       20-23     0.01        a      -                                                              
  0.3557   0.9762       -        -        1g       20-23     0.01        a      -                                                              
  0.4242   0.9547       -        -        1g       20-23     0.01        a      -                                                              
  0.4727   0.9372       -        -        1g       20-23     0.01        a      -                                                              
  0.5112   0.9307       -        -        1g       20-23     0.01        a      -                                                              
  0.5382   0.9141       -        -        1g       20-23     0.01        a      -                                                              
  0.5601   0.9065       -        -        1g       20-23     0.01        a      -                                                              
  0.5777   0.9035       -        -        1g       20-23     0.01        a      -                                                                                     
  0.5924   0.8894       -        -        1g       20-23     0.01        a      -                              
  0.6067   0.8758       -        -        1g       20-23     0.01        a      -                              
  0.6209   0.8618       -        -        1g       20-23     0.01        a      -                              
  0.6357   0.8352       -        -        1g       20-23     0.01        a      -                              
  0.6437   0.8299       -        -        1g       20-23     0.01        a      -                              
  0.6507   0.8226       -        -        1g       20-23     0.01        a      -                              
  0.6611   0.8095       -        -        1g       20-23     0.01        a      -                              
  0.6730   0.7942       -        -        1g       20-23     0.01        a      -                              
  0.6871   0.7613       -        -        1g       20-23     0.01        a      -                              
  0.6924   0.7533       -        -        1g       20-23     0.01        a      -                              
  0.6989   0.7389       -        -        1g       20-23     0.01        a      -                              
  0.7044   0.7123       -        -        1g       20-23     0.01        a      -                              
  0.7085   0.6922       -        -        1g       20-23     0.01        a      -                              
  0.7117   0.6682       -        -        1g       20-23     0.01        a      -                              
  0.7157   0.6416       -        -        1g       20-23     0.01        a      -                              
  0.7191   0.6159       -        -        1g       20-23     0.01        a      -                              
  0.7250   0.5762      5.7083   0.7818    1g       20-23     0.01        a      -                              
  0.7298   0.5621      5.3893   0.8111    1g       20-23     0.01        a      -                              
  0.7402   0.5520      5.1732   0.8070    1g       20-23     0.01        a      -                              
  0.7684   0.5067      4.3126   0.8477    1g       20-23     0.01        a      -                              
  0.7853   0.4748      3.7956   0.8836    1g       20-23     0.01        a      -                              
  0.8031   0.4612      3.5938   0.8467    1g       20-23     0.01        a      -                              
  0.8129   0.4461      3.3814   0.8501    1g       20-23     0.01        a      -                              
  0.2000   1.0000       -        -        2g       20-23     0.01        a      -                              
  0.2086   0.9942       -        -        2g       20-23     0.01        a      -                              
  0.2777   0.9857       -        -        2g       20-23     0.01        a      -    
  0.3285   0.9654       -        -        2g       20-23     0.01        a      -    
  0.3732   0.9652       -        -        2g       20-23     0.01        a      -    
  0.4184   0.9575       -        -        2g       20-23     0.01        a      -    
  0.4497   0.9533       -        -        2g       20-23     0.01        a      -    
  0.4970   0.9294       -        -        2g       20-23     0.01        a      -    
  0.5309   0.9171       -        -        2g       20-23     0.01        a      -    
  0.5622   0.9013       -        -        2g       20-23     0.01        a      -    
  0.5835   0.8889       -        -        2g       20-23     0.01        a      -    
  0.6067   0.8678       -        -        2g       20-23     0.01        a      -    
  0.6299   0.8508       -        -        2g       20-23     0.01        a      -    
  0.6486   0.8330       -        -        2g       20-23     0.01        a      -    
  0.6727   0.7973       -        -        2g       20-23     0.01        a      -    
  0.6869   0.7712       -        -        2g       20-23     0.01        a      -    
  0.6974   0.7579       -        -        2g       20-23     0.01        a      -    
  0.7031   0.7394       -        -        2g       20-23     0.01        a      -    
  0.7099   0.7035       -        -        2g       20-23     0.01        a      -    
  0.7159   0.6544       -        -        2g       20-23     0.01        a      -    
  0.7278   0.6031       -        -        2g       20-23     0.01        a      -    
  0.7302   0.5927       -        -        2g       20-23     0.01        a      -    
  0.7341   0.5678      5.5158   0.7777    2g       20-23     0.01        a      -    
  0.7374   0.5470      5.0697   0.8338    2g       20-23     0.01        a      -    
  0.7397   0.5378      4.8852   0.8565    2g       20-23     0.01        a      -    
  0.7541   0.5198      4.5447   0.8618    2g       20-23     0.01        a      -    
  0.7617   0.5099      4.3681   0.8648    2g       20-23     0.01        a      -    
  0.7749   0.4851      3.9555   0.8947    2g       20-23     0.01        a      -    
  0.7845   0.4725      3.7607   0.8956    2g       20-23     0.01        a      -    
  0.8170   0.4450      3.3664   0.8332    2g       20-23     0.01        a      -    

• Symbols: aW - water activity; mfs - total mass fraction of solutes in the particle, as given by Choi and Chan (2002) and at http://ihome.ust.hk/~keckchan/hygroscopic.html; m denotes the molality of each solute (only for those particles that appear to be fully aqueous); osm - stoichiometric osmotic coefficient, equal to -ln(aW)/(0.0180152 × 4 × m); np - particle number ('bulk' indicates bulk solution meaasurements of equilibrium water activity, suffix e indicates an edb evaporation experiment in an atmosphere of decreasing relative humidity, and suffix g particle growth in an atmosphere of increasing relative humidity); t - experimental temperature (^oC); uncert. - probable uncertainty in the water activity; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - M. Y. Choi and C. K. Chan (2002) Environ. Sci. Technol. 36, 2422-2428.
• The uncertainty associated with mfs for the edb experiments (and so also the molality m) has three sources: the determination of the dc balancing voltage, solute evaporation, and the standardisation of the particle composition to a single reference state (either dilute solution or solid particle). An overall uncertainty of at least ±0.01 seems likely. The corresponding values for molality can be obtained using the conversion equation m = (mfs/(1 - mfs)) × (1000/MW) where MW is the sum of the molar masses of the salt and acid (104.06 + 134.12 g).

(1b) Water Activities of Mixtures with (NH4)2SO4, of Eutonic Composition

   nS/nW      1/aW         aW     mH2Malo  m(NH4)2SO4      t    uncert.   ref.   weight  
  0.351454   1.48173     0.6749   12.005     7.5036      25.0   0.009      a       -                                             -  
  0.351454   1.47578     0.6776   12.005     7.5036      25.0   0.009      a       -                                             -  
  0.351454   1.46846     0.6810   12.005     7.5036      25.0   0.009      a       -                                             -  
  0.125004   1.17226     0.8531    4.2699    2.6689      25.0   0.009      a       -                                             -  
  0.007289   1.01257     0.9876    0.2490    0.1556      25.0   0.009      a       -                                             -  
  0.186871   1.26612     0.7898    6.3832    3.9898      25.0   0.009      a       -                                             -  
  0.010627   1.01715     0.9831    0.3630    0.2269      25.0   0.009      a       -                                             -  
  0.080460   1.10614     0.9040    2.7484    1.7178      25.0   0.009      a       -                                             -  
  0.025131   1.04718     0.9549    0.8584    0.5366      25.0   0.009      a       -                                             -  

• Symbols: nS/nW - moles of total solutes per mole of water; aW - water activity; prefix m denotes molality; t - experimental temperature (^oC); uncert. - uncertainty in the measured water activity (average of the 0.5% to 1.35% in RH given by Wise et al., 2003); ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - M. E. Wise, J. D. Surratt, D. B. Curtis, J. E. Shilling and M. A. Tolbert (2003) J. Geophys. Res. 108, doi:10.1029/2003JD003775, 8 pages.
• The original data of Wise et al. (2003), which are not tabulated in their paper, were obtained directly from the authors. The mole fraction of the acid in the eutonic solution is nH2Malo/(nH2Malo + n(NH4)2SO4) = 0.6154. The uncertainty in this figure is approximately ±0.01. The solutions at the lowest water activity (about 0.68) are simultaneously saturated with respect to both solutes.

(1c) Relative Humidity of Deliquescence of Mixtures with (NH4)2SO4

   DRH    solid    xH2Malo    t       uncert.(a)   uncert.(b)    ref.    weight
  0.740     a      1.0        24.0      0.03        0.05          a        -
  0.710     a      0.845      24.0      0.03        0.05          a        -  
  0.675     a      0.892      24.0      0.03        0.05          a        -
  0.680     a      0.815      24.0      0.03        0.05          a        -
  0.680     a      0.807      24.0      0.03        0.05          a        -
  0.710     a,s    0.645      24.0      0.03        0.05          a        -
  0.765     s      0.265      24.0      0.03        0.05          a        -

• Symbols: DRH - the equilibrium relative humidity (as a fraction, not %) above an aqueous solution saturated with respect to a solid; solid - a (acid), s (salt); xH2Malo - the mole fraction of the acid in the total solute, equal to nH2Malo/(nH2Malo + n(NH4)2SO4); t - experimental temperature (^oC); uncert.(a) - uncertainty in the measured DRH; uncert.(b) - uncertainty in xH2Malo (from Figure 2 of Brooks et al.); ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - S. D. Brooks, M. E. Wise, M. Cushing and M. A. Tolbert (2002) Geophys. Res. Lett. 29, doi:10.1029/2002GL014733.
• These data were extracted from Figure 2 of Brooks et al. The identities of the solids formed do not appear to have been directly determined.

(1d) Relative Humidity of Deliquescence of Mixtures with (NH4)2SO4

   DRH    xH2Malo     T       uncert.    ref.    weight
  0.802    0.0       293.2     0.021       a        -
  0.800    0.121     293.2     0.021       a        -  
  0.782    0.240     293.2     0.021       a        -
  0.762    0.362     293.2     0.021       a        -
  0.723    0.528     293.2     0.021       a        -

• Symbols: DRH - the equilibrium relative humidity (as a fraction, not %) above an aqueous solution saturated with respect to a solid phase; xH2Malo - the mole fraction of the acid in the total solute (neglecting the water content); T - experimental temperature (K); uncert. - uncertainty in the measured DRH; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - M. T. Parsons, D. A. Knopf and A. K. Bertram (2004) J. Phys. Chem. A 108, 11600-11608.
• These data were obtained from Parsons et al., and are shown in their Figure 2.

(2a) Water Activities of Aqueous H2Malo + NaCl Mixtures (1:1 Mole Ratio)

    aW     mfs(orig.)   mfs       m      osm      np    t      uncert.   ref.   weight
  1.0000     0.0000    0.0000   0.0000  1.0000   bulk  22.0     0.003     a      1.0 
  0.9500     0.1398    0.1398   1.0001  0.9490   bulk  22.0     0.003     a      1.0
  0.9200     0.2095    0.2095   1.6304  0.9463   bulk  22.0     0.003     a      1.0
  0.9040     0.2348    0.2348   1.8878  0.9892   bulk  22.0     0.003     a      1.0
  0.8800     0.2717    0.2717   2.2952  1.0305   bulk  22.0     0.003     a      1.0
  0.8410     0.3273    0.3273   2.9941  1.0701   bulk  22.0     0.003     a      1.0
  0.7380     0.4372    0.4372   4.7799  1.1760   bulk  22.0     0.003     a      1.0
  0.3602     0.7728    0.7878     -       -       1e   20-23    0.01      a       - 
  0.3728     0.7695    0.7845     -       -       1e   20-23    0.01      a       - 
  0.4134     0.7651    0.7801     -       -       1e   20-23    0.01      a       - 
  0.4658     0.7458    0.7608     -       -       1e   20-23    0.01      a       - 
  0.4830     0.7284    0.7434     -       -       1e   20-23    0.01      a       - 
  0.5155     0.7069    0.7219     -       -       1e   20-23    0.01      a       - 
  0.5232     0.6132    0.6282  10.3954  1.1529    1e   20-23    0.01      a       -
  0.5317     0.5981    0.6131   9.7529  1.1983    1e   20-23    0.01      a       -
  0.5365     0.5849    0.5999   9.2258  1.2488    1e   20-23    0.01      a       -
  0.5437     0.5819    0.5969   9.1140  1.2371    1e   20-23    0.01      a       -
  0.5718     0.5667    0.5817   8.5574  1.2085    1e   20-23    0.01      a       -
  0.5870     0.5448    0.5598   7.8261  1.2593    1e   20-23    0.01      a       -
  0.6033     0.5370    0.5520   7.5833  1.2332    1e   20-23    0.01      a       -
  0.6257     0.5209    0.5359   7.1062  1.2208    1e   20-23    0.01      a       -
  0.6451     0.5042    0.5192   6.6459  1.2205    1e   20-23    0.01      a       -
  0.6607     0.4879    0.5029   6.2256  1.2317    1e   20-23    0.01      a       -
  0.6822     0.4698    0.4848   5.7907  1.2219    1e   20-23    0.01      a      1.0
  0.6995     0.4560    0.4710   5.4796  1.2068    1e   20-23    0.01      a      1.0
  0.7154     0.4361    0.4511   5.0584  1.2251    1e   20-23    0.01      a      1.0
  0.7358     0.4203    0.4353   4.7437  1.1966    1e   20-23    0.01      a      1.0
  0.7537     0.4042    0.4192   4.4414  1.1779    1e   20-23    0.01      a      1.0
  0.7672     0.3846    0.3996   4.0950  1.1976    1e   20-23    0.01      a      1.0
  0.7786     0.3765    0.3915   3.9598  1.1696    1e   20-23    0.01      a      1.0
  0.7934     0.3601    0.3751   3.6942  1.1591    1e   20-23    0.01      a      1.0
  0.8000     0.3560    0.3710   3.6297  1.1375    1e   20-23    0.01      a      1.0
  0.3734     0.7835    0.7885     -       -       2e   20-23    0.01      a       - 
  0.3810     0.7607    0.7657     -       -       2e   20-23    0.01      a       - 
  0.4126     0.7586    0.7636     -       -       2e   20-23    0.01      a       - 
  0.5087     0.6023    0.6073   9.5172  1.3140    2e   20-23    0.01      a       -
  0.5375     0.5890    0.5940   9.0015  1.2761    2e   20-23    0.01      a       -
  0.5718     0.5646    0.5696   8.1445  1.2698    2e   20-23    0.01      a       -
  0.5877     0.5489    0.5539   7.6400  1.2872    2e   20-23    0.01      a       -
  0.6069     0.5345    0.5395   7.2087  1.2819    2e   20-23    0.01      a       -
  0.6323     0.5211    0.5261   6.8322  1.2416    2e   20-23    0.01      a       -
  0.6428     0.5142    0.5192   6.6453  1.2307    2e   20-23    0.01      a       -
  0.6487     0.5044    0.5094   6.3899  1.2530    2e   20-23    0.01      a       -
  0.6661     0.4881    0.4931   5.9870  1.2555    2e   20-23    0.01      a      1.0
  0.6862     0.4798    0.4848   5.7907  1.2034    2e   20-23    0.01      a      1.0
  0.7049     0.4660    0.4710   5.4789  1.1808    2e   20-23    0.01      a      1.0
  0.7206     0.4531    0.4581   5.2018  1.1656    2e   20-23    0.01      a      1.0
  0.7358     0.4401    0.4451   4.9358  1.1500    2e   20-23    0.01      a      1.0
  0.7591     0.4132    0.4182   4.4229  1.1532    2e   20-23    0.01      a      1.0
  0.7701     0.4006    0.4056   4.1992  1.1508    2e   20-23    0.01      a      1.0
  0.7800     0.3868    0.3918   3.9640  1.1599    2e   20-23    0.01      a      1.0
  0.8000     0.3588    0.3638   3.5196  1.1731    2e   20-23    0.01      a      1.0
  0.1888     0.8791    0.8841     -        -      2e   20-23    0.01      a       -
  0.0873     0.9269    0.9319     -        -      2e   20-23    0.01      a       -
  0.2000     0.9443    0.9443     -        -      1g   20-23    0.01      a       -
  0.3120     0.8936    0.8936     -        -      1g   20-23    0.01      a       -
  0.4093     0.8570    0.8570     -        -      1g   20-23    0.01      a       -
  0.4283     0.8301    0.8301     -        -      1g   20-23    0.01      a       -
  0.4669     0.8029    0.8029     -        -      1g   20-23    0.01      a       -
  0.5027     0.7911    0.7911     -        -      1g   20-23    0.01      a       -
  0.5231     0.7637    0.7637     -        -      1g   20-23    0.01      a       -
  0.5523     0.7524    0.7524     -        -      1g   20-23    0.01      a       -
  0.5755     0.7153    0.7153     -        -      1g   20-23    0.01      a       -
  0.5810     0.6989    0.6989     -        -      1g   20-23    0.01      a       -
  0.5911     0.6795    0.6795     -        -      1g   20-23    0.01      a       -
  0.6018     0.6500    0.6500     -        -      1g   20-23    0.01      a       -
  0.6147     0.6271    0.6271     -        -      1g   20-23    0.01      a       -
  0.6266     0.5942    0.5942     -        -      1g   20-23    0.01      a       -
  0.6343     0.5764    0.5764     -        -      1g   20-23    0.01      a       -
  0.6461     0.5358    0.5358     -        -      1g   20-23    0.01      a       -
  0.6584     0.5088    0.5088   6.3738  1.2134    1g   20-23    0.01      a       -
  0.6782     0.4919    0.4919   5.9579  1.2060    1g   20-23    0.01      a       -
  0.6903     0.4872    0.4872   5.8462  1.1732    1g   20-23    0.01      a       -
  0.7093     0.4567    0.4567   5.1738  1.2282    1g   20-23    0.01      a       -
  0.7218     0.4445    0.4445   4.9244  1.2251    1g   20-23    0.01      a       -
  0.7343     0.4340    0.4340   4.7187  1.2111    1g   20-23    0.01      a       -
  0.7412     0.4239    0.4239   4.5271  1.2242    1g   20-23    0.01      a       -
  0.7573     0.4142    0.4142   4.3505  1.1822    1g   20-23    0.01      a       -
  0.7768     0.3919    0.3919   3.9663  1.1786    1g   20-23    0.01      a       -
  0.8005     0.3661    0.3661   3.5536  1.1589    1g   20-23    0.01      a       -
  0.8088     0.3515    0.3515   3.3355  1.1770    1g   20-23    0.01      a       -
  0.8135     0.3447    0.3447   3.2376  1.1799    1g   20-23    0.01      a       -
  0.2000     0.9450    0.9450      -       -      2g   20-23    0.01      a       -
  0.2169     0.9310    0.9310      -       -      2g   20-23    0.01      a       -
  0.3120     0.9159    0.9159      -       -      2g   20-23    0.01      a       -
  0.4016     0.8818    0.8818      -       -      2g   20-23    0.01      a       -
  0.4343     0.8430    0.8430      -       -      2g   20-23    0.01      a       -
  0.4754     0.8274    0.8274      -       -      2g   20-23    0.01      a       -
  0.5004     0.8059    0.8059      -       -      2g   20-23    0.01      a       -
  0.5263     0.7827    0.7827      -       -      2g   20-23    0.01      a       -
  0.5436     0.7662    0.7662      -       -      2g   20-23    0.01      a       -
  0.5590     0.7542    0.7542      -       -      2g   20-23    0.01      a       -
  0.5707     0.7380    0.7380      -       -      2g   20-23    0.01      a       -
  0.5784     0.7223    0.7223      -       -      2g   20-23    0.01      a       -
  0.5889     0.6969    0.6969      -       -      2g   20-23    0.01      a       -
  0.5989     0.6784    0.6784      -       -      2g   20-23    0.01      a       -
  0.6111     0.6522    0.6522      -       -      2g   20-23    0.01      a       -
  0.6209     0.6358    0.6358      -       -      2g   20-23    0.01      a       -
  0.6329     0.5922    0.5922      -       -      2g   20-23    0.01      a       -
  0.6430     0.5607    0.5607      -       -      2g   20-23    0.01      a       -
  0.6549     0.5246    0.5246      -       -      2g   20-23    0.01      a       -
  0.6625     0.5175    0.5175   6.5994  1.1546    2g   20-23    0.01      a       -
  0.6990     0.4829    0.4829   5.7459  1.1532    2g   20-23    0.01      a       -
  0.7083     0.4753    0.4753   5.5751  1.1445    2g   20-23    0.01      a       -
  0.7177     0.4619    0.4619   5.2833  1.1616    2g   20-23    0.01      a       -
  0.7397     0.4405    0.4405   4.8440  1.1518    2g   20-23    0.01      a       -
  0.7656     0.4044    0.4044   4.1790  1.1823    2g   20-23    0.01      a       -
  0.7970     0.3626    0.3626   3.5011  1.1993    2g   20-23    0.01      a       -
  0.8023     0.3557    0.3557   3.3974  1.1996    2g   20-23    0.01      a       -
  0.8093     0.3444    0.3444   3.2326  1.2112    2g   20-23    0.01      a       -

• Symbols: aW - water activity; mfs(orig.) - total mass fraction of solutes in the particle, as given by Choi and Chan (2002) and at http://ihome.ust.hk/~keckchan/hygroscopic.html; mfs - same as mfs(orig.) but with 0.015 added for particle 1e and 0.005 added for particle 2e, in order to agree better with the bulk solution measurements; m denotes the molality of each solute (only for those particles that appear to be fully aqueous); osm - stoichiometric osmotic coefficient, equal to -ln(aW)/(0.0180152 × 3 × m); np - particle number ('bulk' indicates bulk solution meaasurements of equilibrium water activity, suffix e indicates an edb evaporation experiment in an atmosphere of decreasing relative humidity, and suffix g particle growth in an atmosphere of increasing relative humidity); t - experimental temperature (^oC); uncert. - probable uncertainty in the water activity; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values. Clegg and Seinfeld (2006b) fitted only data for evaporation experiments, for solute molalities below 6.0 mol kg^-1.
• Source: a - M. Y. Choi and C. K. Chan (2002) Environ. Sci. Technol. 36, 2422-2428.
• The uncertainty associated with mfs for the edb experiments (and so also the molality m) has three sources: the determination of the dc balancing voltage, solute evaporation, and the standardisation of the particle composition to a single reference state (either dilute solution or solid particle). An overall uncertainty of at least ±0.01 seems likely. The corresponding values for molality can be obtained using the conversion equation m = (mfs/(1 - mfs)) × (1000/MW) where MW is the sum of the molar masses of the salt and acid (104.06 + 58.44 g).

(2b) Dissociation Constants of Malonic Acid in Aqueous NaCl

  mNaCl    mH2Malo    mNaOH      pQa1    pQa2      t     uncert.   ref.  weight  
  0.09797  0.003998   0.001999   2.620    -      24.89    0.012     a      1.0  
  0.09797  0.003998   0.001999   2.620    -      24.9     0.012     a      1.0  
  0.3265   0.01333    0.006661   2.555    -      24.90    0.009     a      1.0  
  0.980    0.040      0.02       2.528    -      24.9     0.008     a      1.0  
  2.988    0.024      0.01211    2.671    -      24.89    0.008     a      1.0  
  4.980    0.04       0.02018    2.889    -      24.9     0.008     a      1.0  
  0.09191  0.003996   0.006        -     5.251   24.91    0.011     a      1.0   
  0.3065   0.01332    0.02001      -     5.079   24.92    0.011     a      1.0    
  0.919    0.03995    0.06         -     4.962   24.9     0.011     a      1.0   
  2.954    0.02402    0.03612      -     5.028   24.91    0.011     a      1.0   
  4.924    0.04003    0.0602       -     5.286   24.9     0.011     a      1.0   

• Symbols: prefix m denotes molality; pQa1 - -log10(Qa1) where Qa1 is the stoichiometric first dissociation constant of malonic acid (H2Malo), equal to mH⁺ × mHMalo⁻ / mH2Malo; pQa2 - -log10(Qa2) where Qa2 is the stoichiometric second dissociation constant of H2Malo, equal to mH⁺ × mMalo²⁻ / mHMalo⁻; t - experimental temperature (^oC); uncert. - probable uncertainty in the values of pQa1 and pQa2; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - R. M. Kettler, D. A. Palmer and D. J. Wesolowski (1992) J. Solution Chem. 21, 883-900.
• The work of Kettler et al. should be consulted if the original emf data are required. The results in the table above are from their Tables III and IV.

(2c) Dissociation Constants of Malonic Acid in Aqueous NaCl

  MNaCl   mNaCl   pQa1(M)  ln(Qa1)    t    ln(Qa1)(25 C)   ref.  weight
  0.10   0.1003   2.634    -6.060   18.0      -6.048        a     1.0 
  0.20   0.2009   2.609    -6.003   18.0      -5.986        a     1.0
  0.50   0.5050   2.554    -5.871   18.0      -5.848        a     1.0 
  1.0    1.0194   2.560    -5.875   18.0      -5.845        a     1.0 
  1.5    1.5444   2.594    -5.944   18.0      -5.908        a     1.0 
  2.0    2.0807   2.627    -6.009   18.0      -5.969        a     1.0 
  2.5    2.6294   2.693    -6.150   18.0      -6.105        a     1.0 
  3.0    3.191    2.747    -6.263   18.0      -6.214        a     1.0 

• Symbols: prefix M denotes molarity at the experimental temperature of 18 ^oC; m denotes molality; pQa1(M) - minus log to the base 10 of the stoichiometric first dissociation constant of H2Malo on a molar basis at 18 ^oC, equal to MH⁺ × MHMalo⁻ / MH2Malo, taken from Adell's Table 2; Qa1 - the stoichiometric first dissociation constant of H2Malo on a molality basis at 18 ^oC, equal to mH⁺ × mHMalo⁻ / mH2Malo and calculated from pQa1(M); t - experimental temperature (^oC); Qa1(25 C) - the value of Qa1 adjusted to 298.15 K using enthalpy and heat capacity changes for the dissociation reaction listed in Table V of R. M. Kettler, D. A. Palmer and D. J. Wesolowski (1992) J. Solution Chem. 21, 883-900; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - B. Adell (1939) Z. physik. Chem. A185, 161-206.
• Adell also presents data for the dissociation of several other acids in aqueous NaCl at 18 ^oC.

(2d) Dissociation Constants of Malonic Acid in Aqueous NaCl

  MNaCl    mNaCl    pQa2(M)  ln(Qa2)  ln(Qa2)(25 C)    t     ref.  weight
  0.10     0.1003    5.240   -12.063     -12.098      18.0    a      1.0 
  0.20     0.2009    5.154   -11.863     -11.896      18.0    a      1.0 
  0.50     0.5050    5.037   -11.588     -11.616      18.0    a      1.0 
  1.00     1.0194    4.969   -11.422     -11.443      18.0    a      1.0 
  1.50     1.5444    4.961   -11.394     -11.409      18.0    a      1.0 
  2.00     2.0807    4.990   -11.450     -11.458      18.0    a      1.0 
  2.50     2.6294    5.037   -11.548     -11.548      18.0    a      1.0 
  3.00     3.191     5.100   -11.681     -11.674      18.0    a      1.0 

• Symbols: prefix M denotes molarity at the experimental temperature of 18 ^oC; m denotes molality; pQa2(M) - minus log to the base 10 of the stoichiometric second dissociation constant of H2Malo on a molar basis at 18 ^oC, equal to MH⁺ × MMalo²⁻ / MHMalo⁻, taken from Adell's Table 2; Qa2 - the stoichiometric second dissociation constant of H2Malo on a molality basis at 18 ^oC, equal to mH⁺ × mMalo²⁻ / mHMalo⁻ and calculated from pQa2(M); t - experimental temperature (^oC); Qa2(25 C) - the value of Qa2 adjusted to 298.15 K using enthalpy and heat capacity changes for the dissociation reaction listed in Table V of R. M. Kettler, D. A. Palmer and D. J. Wesolowski (1992) J. Solution Chem. 21, 883-900; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - B. Adell (1939) Z. physik. Chem. A185, 161-206.
• Adell also presents data for the dissociation of several other acids in aqueous NaCl at 18 ^oC.

(3a) Solubilities of H2Malo in Aqueous HCl Solutions

  MHCl     MH2Malo   mHCl   mH2Malo      t     ref.   weight        
  0.0      7.505     0.0     15.3       25.0    a       -        
  1.0(a)   6.29(a)   1.85    11.6       25.0    a      1.0       
  2.0(a)   5.44(a)   3.45     9.40      25.0    a      1.0       
  3.0(a)   4.71(a)   4.93     7.75      25.0    a      1.0       
  4.0(a)   4.08(a)   6.38     6.47      25.0    a      1.0       
  5.0(a)   3.55(a)   7.75     5.50      25.0    a      0.0       
  4.443    3.85      6.98     6.05      25.0    a      0.0       
  6.210    2.995     9.44     4.55      25.0    a      0.0   

• Prefix M denotes molarity; m - molality; t - experimental temperature (^oC); ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - J. Knox and M. B. Richards (1919) J. Chem. Soc., Trans., 115, 508-531.
• Pairs of concentrations marked (a) were interpolated, as Knox and Richards (1919) did not make measurements at low concentrations.
• Molalities at the experimental temperature t (the third and fourth columns in the table) were calculated from the measured molarities by assuming that the molar volumes of both solutes were the same as in pure aqueous solutions at the same molarities as in the mixture. Densities of pure aqueous malonic acid have been measured at 20 ^oC, from 0.01893 to 4.8452 mol kg^-1, by King and Mangler (1922) and are tabulated in: J. Timmermans (1960) The Physico-Chemical Constants of Binary Systems in Concentrated Solutions, Vol. 4, Interscience Publishers. The concentration of malonic acid in a saturated solution at 25 ^oC is given by Knox and Richards as 7.705 mol dm^-3, and in Table 1154 of H. Stephen and T. Stephen (Solubilities of Inorganic and Organic Compounds; Pergamon: Oxford, Vol. 1, 1979) as 7.33 mol dm^-3. The solubility, in mass units, is about 15.3 mol kg^-1. Combining the two sets of values yields densities of the saturated solution of 1271 g dm^-3 to 1241.5 g dm^-3 . Adjusting the King and Mangler data to 25 ^oC by adding the difference between the densities of pure water at 20 ^oC and 25 ^oC, and fitting over the full concentration range yields the following two expressions for the density of aqueous malonic acid at 25 ^oC: d (g dm^-3) = 0.99705 + 0.029371 × m - 0.000811224 × m², and d = 0.99705 + 0.02866 × M - 0.002369 × M^1.5.

(3b) Solubilities of H2Malo in Aqueous H2SO4 Solutions

  MH2SO4   MH2Malo  mH2SO4   mH2Malo      t     ref.  weight      
  0.0       7.505    0.0      15.6       25.0    a      -          
  1.364     5.72     2.486    10.43      25.0    a     1.0         
  3.525     3.395    5.709     5.50      25.0    a     1.0         
  5.88      2.035    9.683     3.35      25.0    a     1.0         

• Symbols: prefix M denotes molarity; m - molality; t - experimental temperature (^oC); ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - J. Knox and M. B. Richards (1919) J. Chem. Soc., Trans., 115, 508-531.
• Molalities at the experimental temperature t (the third and fourth columns in the table) were calculated from the measured molarities by assuming that the molar volumes of both solutes were the same as in pure aqueous solutions at the same molarities as in the mixture. See the notes to the table on H2Malo solubilities in aqueous HCl for details of how densities of pure aqueous malonic acid were obtained.

(4) Osmotic Coefficients of Aqueous NaHMalo

  mNaHMalo   mNaCl(ref)   osm      t    uncert.   ref.   weight 
   0.3995     0.3850     0.8871   25.0   0.009     a      1.0          
   0.4305     0.4141     0.8856   25.0   0.009     a      1.0          
   0.9282     0.8676     0.8712   25.0   0.009     a      1.0          
   1.407      1.277      0.8615   25.0   0.009     a      1.0     
   1.799      1.605      0.8612   25.0   0.009     a      1.0    
   2.131      1.863      0.8561   25.0   0.009     a      1.0    
   2.247      1.960      0.8588   25.0   0.009     a      1.0    
   2.850      2.422      0.8599   25.0   0.009     a      1.0    
   3.080      2.573      0.8531   25.0   0.009     a      0.5    
   3.451      2.855      0.8597   25.0   0.009     a      1.0       
   3.849      3.125      0.8582   25.0   0.009     a      1.0     
   4.765      3.727      0.8590   25.0   0.009     a      1.0    

• Symbols: prefix m denotes molality; osm - molal osmotic coefficient; t - experimental temperature (^oC); uncert. - assumed uncertainty in the osmotic coefficient (see note below); ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - J. M. Stokes (1948) J. Amer. Chem. Soc. 70, 1944-1946.
• The author states that the results are probably accurate to 1%. The value listed in the uncertainty column above assumes that this 1% applies to the calculated osmotic coefficients rather than the isopiestic molalities of the aqueous NaHMalo, or NaCl reference solutions (NaCl(ref)).
• The osmotic coefficients have been recalculated to modern values for the NaCl reference solutions given by: D. G. Archer (1992) J. Phys. Chem. Ref. Data 21, 793-829.

(5a) Mean Activity Coefficients of NaCl in Aqueous NaCl - NaHMalo Solutions

  yB       I        dE      -log10(gamma)    t     uncert.   ref.   weight 
  0.      0.5000    0.0        0.1672       25.0    0.08      a      1.0         
  0.4     0.5000   13.18       0.1677       25.0    0.08      a      1.0  
  0.6     0.5000   23.56       0.1674       25.0    0.08      a      1.0  
  0.8     0.5000   41.29       0.1667       25.0    0.08      a      1.0  
  0.      1.000     0.0        0.1823       25.0    0.08      a      1.0  
  0.2002  1.000     5.72       0.1821       25.0    0.08      a      1.0  
  0.3999  1.000    13.32       0.1840       25.0    0.08      a      1.0  
  0.5997  1.000    23.84       0.1850       25.0    0.08      a      1.0  
  0.7998  1.000    41.82       0.1865       25.0    0.08      a      1.0  
  0       2.000     0.0        0.1734       25.0    0.08      a      1.0  
  0.2002  2.000     6.10       0.1764       25.0    0.08      a      1.0  
  0.3999  2.000    13.89       0.1799       25.0    0.08      a      1.0  
  0.6     2.000    24.90       0.1849       25.0    0.08      a      1.0  
  0.8001  2.000    43.11       0.1882       25.0    0.08      a      1.0  
  0.      3.000     0.0        0.1439       25.0    0.08      a      1.0  
  0.1999  3.000     6.72       0.1523       25.0    0.08      a      1.0  
  0.3999  3.000    15.07       0.1604       25.0    0.08      a      1.0  
  0.6001  3.000    26.68       0.1704       25.0    0.08      a      1.0  
  0.8     3.000    45.43       0.1784       25.0    0.08      a      1.0  
  0.      4.001     0.0        0.1037       25.0    0.08      a      1.0  
  0.1998  4.001     7.00       0.1147       25.0    0.08      a      1.0  
  0.4001  4.001    16.07       0.1286       25.0    0.08      a      1.0  
  0.6000  4.001    27.94       0.1409       25.0    0.08      a      1.0  
  0.7999  4.001    47.06       0.1520       25.0    0.08      a      1.0  

• Symbols: yB denotes the stoichiometric ionic strength fraction of NaHMalo in solution, equal to mNaHMalo/I; I - stoichiometric molal ionic strength, assuming no dissociation of the hydrogen malonate ion, and equal to mNaHMalo + mNaCl; dE - the difference in emf (mV) between the cell Na-glass|NaCl(mA), NaHMalo(mB), AgCl(s)|Ag and the reference cell Na-glass|NaCl(mA + mB), AgCl(s)|Ag; gamma - mean activity coefficient of NaCl in the solution, adjusted to values for the pure aqueous NaCl reference solution from D. G. Archer (1992) J. Phys. Chem. Ref. Data 21, 793-829; t - experimental temperature (^oC); uncert. - uncertainty in dE given by Esteso et al.; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - M. A. Esteso, L. Fernandez-Merida and D. M. Grandoso (1989) J. Chem. Thermo. 21, 1279-1285.

(5b) EMF Measurements Yielding Stoichiometric Activities of HCl

   mNaCl     mNaHMalo   mNa2Malo    dE      t     uncert.   ref.  weight
  0.009899   0.009899   0.009899  315.93   25.0    0.15      a      1.0  
  0.01984    0.01984    0.01984   295.02   25.0    0.15      a      1.0                            
  0.02980    0.02980    0.02980   282.96   25.0    0.15      a      1.0                            
  0.03988    0.03988    0.03988   273.84   25.0    0.15      a      1.0                            
  0.05       0.05       0.04999   266.60   25.0    0.15      a      1.0                            
  0.07004    0.07004    0.07004   256.26   25.0    0.15      a      1.0                            
  0.07212    0.07212    0.07212   255.40   25.0    0.15      a      1.0                            
  0.09050    0.09050    0.09050   248.17   25.0    0.15      a      1.0                            
  0.1226     0.1226     0.1227    238.68   25.0    0.15      a      1.0                            
  0.3012     0.3012     0.3014    208.60   25.0    0.15      a      1.0                            
  0.3999     0.3999     0.4002    198.94   25.0    0.15      a      1.0                            
  0.4824     0.4824     0.4819    192.99   25.0    0.15      a      1.0                            
  0.5908     0.5908     0.5902    185.97   25.0    0.15      a      1.0                            
  0.7068     0.7068     0.7061    179.55   25.0    0.15      a      1.0                            
  0.8001     0.8001     0.7994    175.51   25.0    0.15      a      1.0                            

• Symbols: prefix m denotes molality; dE - the difference in emf (mV) between the cell H-glass|NaHMal(m), Na2Malo(m), NaCl(m), AgCl(s)|Ag and the reference cell H-glass|HCl(mR = 0.1007), AgCl(s)|Ag; t - experimental temperature (^oC); uncert. - probable uncertainty in the emf measurement (mV) given by Fernandez-Merida et al.; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - L. Fernandez-Merida, F. Hernandez-Luis, O. M. Gonzalez-Siaz and M. A. Esteso (1992) J. Electroanal. Chem. 335, 11-17.
• The HCl activity in the solution is related to the EMF by: E = E^o + (RT/F)ln(mH⁺ × mCl⁻⁻ × gamma²) where E^o is the standard EMF of the cell (0.22245 V at 298.15 K), R = 8.3144 J mol^-1 K^-1, T = 298.15 K, F = 96484.5 C mol^-1, and gamma is the mean activity coefficient of HCl in the solution.
• An offset of about 0.2 to 0.5 mV was found between the above data and those of Hamer et al. (tabulated further below), when converted to the same basis (see Clegg and Seinfeld, 2006b).

(6) Water Activities of Aqueous Na2Malo

   aW    mfs(orig.)   mfs       osm       np    mNa2Malo   t     uncert.   weight
  0.997    0.0150    0.0150    0.5404    bulk    0.1029   25.0    0.003      0.0 
  0.981    0.0674    0.0674    0.7270    bulk    0.4882   25.0    0.003      1.0 
  0.957    0.1262    0.1262    0.8335    bulk    0.9756   25.0    0.003      1.0 
  0.931    0.1780    0.1780    0.9043    bulk    1.4628   25.0    0.003      1.0 
  0.908    0.2179    0.2179    0.9487    bulk    1.8820   25.0    0.003      1.0 
  0.880    0.2606    0.2606    0.9934    bulk    2.3808   25.0    0.003      1.0 
  0.9031   0.2257    0.2157    1.0150     1e     1.8578   25.0    0.01       1.0 
  0.9140   0.2097    0.1997    0.9870     1e     1.6856   25.0    0.01       1.0 
  0.9307   0.1763    0.1663    0.9861     1e     1.3474   25.0    0.01       1.0 
  0.8500   0.3143    0.3043    1.0176     1e     2.9546   25.0    0.01       1.0 
  0.7947   0.3696    0.3596    1.1208     1e     3.7931   25.0    0.01       1.0 
  0.6556   0.4937    0.4837    1.2343     1e     6.3284   25.0    0.01       1.0 
  0.5559   0.5891    0.5791    1.1688     1e     9.2938   25.0    0.01       1.0 
  0.4457   0.6746    0.6646    1.1169     1e    13.385    25.0    0.01       1.0 
  0.0780   0.9331    0.9231      -        1e       -      25.0    0.01       -   
  0.9031   0.2257    0.2157    1.0150     2e     1.8578   25.0    0.01       1.0 
  0.8604   0.2948    0.2848    1.0341     2e     2.6899   25.0    0.01       1.0 
  0.7755   0.4171    0.4071    1.0141     2e     4.6381   25.0    0.01       1.0 
  0.7336   0.4540    0.4440    1.0625     2e     5.3942   25.0    0.01       1.0 
  0.6234   0.5107    0.5007    1.2906     2e     6.7739   25.0    0.01       1.0 
  0.5850   0.5620    0.5520    1.1917     2e     8.3230   25.0    0.01       1.0 
  0.4885   0.6400    0.6300    1.1524     2e    11.502    25.0    0.01       1.0 
  0.4284   0.7059    0.6959    1.0145     2e    15.458    25.0    0.01       1.0 
  0.3528   0.7867    0.7767    0.8204     2e    23.496    25.0    0.01       1.0 
  0.2514   0.8894    0.8794      -        2e       -      25.0    0.01       -   
  0.1479   0.9156    0.9056      -        2g       -      25.0    0.01       -   
  0.2074   0.8995    0.8895      -        2g       -      25.0    0.01       -   
  0.3077   0.8334    0.8234    0.6923     2g    31.495    25.0    0.01       1.0 
  0.4062   0.7524    0.7424    0.8561     2g    19.468    25.0    0.01       1.0 
  0.7023   0.4767    0.4667    1.1060     2g     5.9114   25.0    0.01       1.0 
  0.0470   0.9046    0.8946      -        3g       -      25.0    0.01       -   
  0.5111   0.6135    0.6035    1.2077     3g    10.282    25.0    0.01       1.0 
  0.8096   0.3604    0.3504    1.0724     3g     3.6437   25.0    0.01       1.0 

• Symbols: aW - water activity; mfs(orig.) - mass fraction of solute in the particle, as given by Peng and Chan (2001) and at http://ihome.ust.hk/~keckchan/hygroscopic.html; mfs - mass fraction of solute in the particle adjusted by subtracting 0.01 from mfs(orig.) (edb data only), to better agree with the bulk measurements; prefix m denotes solute molality calculated from mfs (only for those particles that appear to be fully aqueous); osm - stoichiometric osmotic coefficient, equal to -ln(aW)/(0.0180152 × 3 × m); np - particle number (bulk indicates bulk solution meaasurements of equilibrium water activity, suffix e indicates an edb evaporation experiment in an atmosphere of decreasing relative humidity, and g particle growth in an atmosphere of increasing relative humidity); t - experimental temperature (^oC); uncert. - probable uncertainty in the water activity; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - C. Peng and C. K. Chan (2001) Atmos. Environ. 35, 1183-1192.
• The uncertainty associated with mfs for the edb experiments (and so also the molality m) has three sources: the determination of the dc balancing voltage, solute evaporation, and the standardisation of the particle composition to a single reference state (either dilute solution or solid particle). An overall uncertainty of at least ±(0.01 to 0.02) seems likely. The corresponding values for molality can be obtained using the conversion equation m = (mfs/(1 - mfs)) × (1000/MW) where MW is the molar mass of the salt (148.04 g).

(7) Activity Coefficients of NaCl in Aqueous NaCl - Na2Malo Mixtures

    I       yB    -log10(gamma)    t     uncert.  ref.   weight     
  0.02497   0.0      0.0657       25.0    0.01     a      1.0        
  0.02497   0.4      0.0678       25.0    0.01     a      1.0        
  0.02497   0.7      0.0694       25.0    0.01     a      1.0        
  0.02497   0.95     0.0699       25.0    0.01     a      1.0        
  0.02497   1.0      0.0705(a)    25.0    0.01     a      1.0        
  0.05000   0        0.0859       25.0    0.01     a      1.0        
  0.05000   0.25     0.0865       25.0    0.01     a      1.0        
  0.05000   0.5001   0.0872       25.0    0.01     a      1.0        
  0.05010   0.7503   0.0870       25.0    0.01     a      1.0        
  0.0500    1.0      0.0876(a)    25.0    0.01     a      1.0        
  0.07500   0.0      0.0994       25.0    0.01     a      1.0        
  0.07500   0.25     0.1000       25.0    0.01     a      1.0        
  0.07499   0.5001   0.1116       25.0    0.01     a      0.0        
  0.07500   0.7500   0.1010       25.0    0.01     a      1.0        
  0.07500   1.0      0.1017(a)    25.0    0.01     a      1.0        
  0.10000   0.0      0.1095       25.0    0.01     a      1.0        
  0.10000   0.2501   0.1101       25.0    0.01     a      1.0        
  0.10000   0.5001   0.1117       25.0    0.01     a      1.0        
  0.10000   0.9500   0.1129       25.0    0.01     a      1.0        
  0.10000   1.00     0.1132(a)    25.0    0.01     a      1.0        
  0.25000   0.0      0.1435       25.0    0.01     a      1.0        
  0.25000   0.1999   0.1446       25.0    0.01     a      1.0        
  0.25000   0.4000   0.1473       25.0    0.01     a      1.0        
  0.25000   0.6000   0.1492       25.0    0.01     a      1.0        
  0.25020   0.7994   0.1504       25.0    0.01     a      1.0        
  0.25000   0.9500   0.1516       25.0    0.01     a      1.0        
  0.25000   1.00     0.1523(a)    25.0    0.01     a      1.0        
  0.50000   0.0      0.1672       25.0    0.01     a      1.0        
  0.50000   0.2      0.1706       25.0    0.01     a      1.0        
  0.50000   0.6      0.1767       25.0    0.01     a      1.0        
  0.49990   0.8      0.1789       25.0    0.01     a      1.0        
  0.49990   0.95     0.1837       25.0    0.01     a      1.0        
  0.50000   1.0      0.1834(a)    25.0    0.01     a      1.0        
  0.75000   0.0      0.1778       25.0    0.01     a      1.0        
  0.74990   0.2000   0.1828       25.0    0.01     a      1.0        
  0.74990   0.4001   0.1858       25.0    0.01     a      1.0        
  0.75000   0.600    0.1907       25.0    0.01     a      1.0        
  0.75020   0.7998   0.1957       25.0    0.01     a      1.0        
  0.75000   1.0      0.1996(a)    25.0    0.01     a      1.0        
  1.00000   0.0      0.1823       25.0    0.01     a      1.0        
  1.00000   0.200    0.1886       25.0    0.01     a      1.0        
  1.00100   0.5997   0.2009       25.0    0.01     a      1.0        
  1.00000   0.8000   0.2058       25.0    0.01     a      1.0        
  1.00000   0.9500   0.2113       25.0    0.01     a      1.0        
  1.00000   1.00     0.2125(a)    25.0    0.01     a      1.0        
  2.00000   0.0      0.1734       25.0    0.01     a      1.0        
  2.00000   0.2002   0.1856       25.0    0.01     a      1.0        
  1.99900   0.6002   0.2130       25.0    0.01     a      1.0        
  2.00000   0.800    0.2244       25.0    0.01     a      1.0        
  2.00000   0.950    0.2361       25.0    0.01     a      1.0        
  2.00000   1.0      0.2386(a)    25.0    0.01     a      1.0        
  3.00000   0.0      0.1439       25.0    0.01     a      1.0        
  3.00000   0.1999   0.1652       25.0    0.01     a      1.0        
  3.00000   0.400    0.1851       25.0    0.01     a      1.0        
  3.00000   0.600    0.2047       25.0    0.01     a      1.0        
  3.00900   0.8008   0.2243       25.0    0.01     a      1.0        
  3.00000   1.0      0.2447(a)    25.0    0.01     a      1.0        

• I - stoichiometric molal ionic strength; yB - the stoichiometric ionic strength fraction of Na2Malo in solution, equal to 3mNa2Malo/(3mNa2Malo + mNaCl); gamma - the measured mean activity coefficient of NaCl in the solution, adjusted to values for the pure aqueous NaCl reference solution from D. G. Archer (1992) J. Phys. Chem. Ref. Data 21, 793-829; t - experimental temperature (^oC); uncert. - claimed uncertainty in the emf measurements (mV) from which gamma is determined; ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - L. Fernandez-Merida, F. Hernandez-Luis, H. R. Galleguillos and M. A. Esteso (1993) Portugal. Electrochim. Acta 11, 225-235.
• The mean activity coefficient of NaCl is determined from differences in the emfs of the cells Na-glass|NaCl(mA), Na2Malo(mB), AgCl(s)|Ag and the reference cell Na-glass|NaCl(mA + 3mB), AgCl(s)|Ag. Values of gamma marked (a), for pure aqueous Na2Malo, are extrapolations by Fernandez-Merida et al. based on Harned's rule.

(8) EMF Measurements Yielding Stoichiometric Activities of HCl

      m         E(int.)    t      uncert.   ref.  weight 
  0.0009867     733.5     25.0     0.15      a     1.0     
  0.0010619     731.4     25.0     0.15      a     1.0    
  0.0011095     730.23    25.0     0.15      a     1.0    
  0.0019114     715.08    25.0     0.15      a     1.0    
  0.0019420     714.44    25.0     0.15      a     1.0    
  0.0024182     708.53    25.0     0.15      a     1.0    
  0.0029128     703.29    25.0     0.15      a     1.0    
  0.0030385     701.95    25.0     0.15      a     1.0    
  0.0040020     694.42    25.0     0.15      a     1.0    
  0.0047561     689.45    25.0     0.15      a     1.0    
  0.0050248     687.67    25.0     0.15      a     1.0    
  0.0068161     679.21    25.0     0.15      a     1.0    
  0.0068596     678.77    25.0     0.15      a     1.0    
  0.0094543     669.57    25.0     0.15      a     1.0    
  0.0095398     669.23    25.0     0.15      a     1.0    
  0.018622      649.30    25.0     0.15      a     1.0    
  0.029535      635.40    25.0     0.15      a     1.0    
  0.044566      622.63    25.0     0.15      a     1.0                               

• Symbols: m is molality (see note below regarding solution composition); E(int.) - emf (mV, on the international scale) of the cell Pt(H2)|NaHMalo(m), Na2Malo(m), NaCl(m) |AgCl(s),Ag, yielding stoichiometric activities of HCl; t - experimental temperature (^oC); uncert. - probable uncertainty in the EMF measurement (mV); ref. - source of data; weight - the weight assigned in the fit of the model to determine parameter values.
• Source: a - W. J. Hamer, J. O. Burton and S. F. Acree (1940) J. Res. Nat. Bur. Stand. 24, 269-292.
• The emfs can be converted to V by multiplying the listed values by the factor 1.00033/1000. The solutions are equimolal mixtures of NaCl, NaHMalo, and Na2Malo, with each component at molality m. The HCl activity in the solution is related to the EMF by: E = E^o - (RT/F)ln(mH × mCl⁻ × gamma²) where E^o is the standard EMF of the cell (0.22245 V at 298.15 K), R = 8.3144 J mol^-1 K^-1, T = 298.15 K, F = 96484.5 C mol^-1, and gamma is the mean activity coefficient of HCl in the solution.