Model II Data

The System

The sources of data used to determine mixture parameters W, Q and U in the activity coefficient equations for this ternary (3 ion) system are listed in Table 6 of Clegg et al. (1998a). Fits of the model are described in section 3.8 of that paper. The following types of data were considered:

Solubilities of the solids NH4NO3(s), (NH4)2SO4.3NH4NO3(s), (NH4)2SO4.2NH4NO3(s), (NH4)2SO4(s), and ice in the ternary solutions.
Water activities from electrodynamic balance measurements.
Equilibrium vapour pressures of water (not fitted).

References: S. L. Clegg, P. Brimblecombe and A. S. Wexler (1998a) J. Phys. Chem. A 102, 2137-2154.

Weights

The values listed in the tables below are based upon those used in the fits of the model. However, they have been normalised for each type of measurement so that the maximum weight for a data point in each table is always unity. Points given zero weight are those which either appear to be in error, or are used for comparison only (and were not fitted). Points with a weight of "-" are outside the temperature or concentration limits of the current model, and have not been assessed for accuracy.

The Data

The experimental data used to fit the activity coefficient model are listed in the tables below. Notes at the end of each one define the tabulated quantities, and identify the sources of the measurements.

(1) Solubilities of Solid Phases

   mNH4NO3   m(NH4)2SO4     t    solid     ref.    weight   
    14.779      0.000      0.0     1     a(2139)     1.0   
    13.674      1.012      0.0     1     a(2139)     1.0   
    12.917      1.621      0.0     1     a(2139)     1.0                         
    12.917      1.621      0.0     4     a(2139)     0.2                         
     8.078      3.019      0.0     4     a(2139)     0.2                         
     7.919      3.175      0.0     4     a(2139)     0.2                         
     7.919      3.175      0.0     5     a(2139)     0.1                         
     7.986      3.179      0.0     5     a(2139)     0.1                         
     7.622      3.304      0.0     5     a(2139)     0.1                         
     1.240      5.075      0.0     6     a(2139)     1.0                         
     0.000      5.347      0.0     6     a(2139)     1.0                         
    29.290      0.000     30.0     1     a(2139)     1.0                         
    28.173      0.601     30.0     1     a(2139)     1.0   
    28.240      0.884     30.0     1     a(2139)     1.0   
    28.240      0.884     30.0     4     a(2139)     0.2   
    25.563      1.203     30.0     4     a(2139)     0.2   
    21.501      1.844     30.0     4     a(2139)     0.2   
    21.501      1.844     30.0     5     a(2139)     0.1   
    18.393      2.412     30.0     5     a(2139)     0.1   
    16.847      2.719     30.0     5     a(2139)     0.1   
    16.847      2.719     30.0     6     a(2139)     1.0   
    10.728      3.403     30.0     6     a(2139)     1.0   
     4.853      4.256     30.0     6     a(2139)     1.0   
     2.827      4.932     30.0     6     a(2139)     1.0   
     0.000      5.971     30.0     6     a(2139)     1.0   
    65.736      0.000     70.0     1     a(2139)      -    
    62.721      1.125     70.0     1     a(2139)      -    
    61.190      1.121     70.0     1     a(2139)      -    
    61.190      1.121     70.0     4     a(2139)      -    
    58.734      1.188     70.0     4     a(2139)      -    
    47.410      1.496     70.0     4     a(2139)      -    
    42.938      1.819     70.0     4     a(2139)      -    
    42.938      1.819     70.0     5     a(2139)      -    
    39.569      1.949     70.0     5     a(2139)      -    
    37.874      2.195     70.0     5     a(2139)      -    
    37.874      2.195     70.0     6     a(2139)      -    
     2.884      6.422     70.0     6     a(2139)      -    
     0.000      6.933     70.0     6     a(2139)      -    
    14.785      0.000      0.0     1     a(2140)     1.0   
    14.104      0.543      0.0     1     a(2140)     1.0   
    13.438      1.429      0.0     1     a(2140)     1.0   
    13.155      1.749      0.0     1     a(2140)     1.0   
    13.155      1.749      0.0     4     a(2140)     0.0   
     9.952      2.437      0.0     4     a(2140)     0.2   
     9.081      2.830      0.0     4     a(2140)     0.2   
     8.329      3.253      0.0     4     a(2140)     0.2   
     9.232      2.772      0.0     4     a(2140)     0.2   
     9.232      2.772      0.0     5     a(2140)     0.1   
     8.225      3.216      0.0     5     a(2140)     0.1   
     7.509      3.408      0.0     5     a(2140)     0.1   
     7.509      3.408      0.0     6     a(2140)     1.0   
     6.076      4.087      0.0     6     a(2140)     1.0   
     4.598      4.385      0.0     6     a(2140)     1.0   
     3.043      4.552      0.0     6     a(2140)     1.0   
     1.744      4.747      0.0     6     a(2140)     1.0   
     1.032      5.001      0.0     6     a(2140)     1.0   
     0.495      5.158      0.0     6     a(2140)     1.0   
     0.000      6.318      0.0     6     a(2140)     0.0   
    26.306      0.000     25.0     1     a(2140)     1.0   
    26.051      0.525     25.0     1     a(2140)     1.0   
    25.183      0.976     25.0     1     a(2140)     1.0   
    25.065      1.122     25.0     1     a(2140)     1.0   
    25.065      1.122     25.0     4     a(2140)     0.0   
    23.036      1.205     25.0     4     a(2140)     0.2   
    21.137      1.628     25.0     4     a(2140)     0.2   
    19.890      1.822     25.0     4     a(2140)     0.2   
    18.141      2.177     25.0     4     a(2140)     0.2   
    18.141      2.177     25.0     5     a(2140)     0.1   
    22.115      1.627     25.0     5     a(2140)     0.1   
    19.410      2.052     25.0     5     a(2140)     0.1   
    16.658      2.523     25.0     5     a(2140)     0.1   
    14.634      2.923     25.0     5     a(2140)     0.1   
    14.035      2.993     25.0     5     a(2140)     0.1   
    14.035      2.993     25.0     6     a(2140)     1.0   
     9.830      3.638     25.0     6     a(2140)     1.0   
     7.332      4.025     25.0     6     a(2140)     1.0   
     5.022      4.526     25.0     6     a(2140)     1.0   
     3.501      4.837     25.0     6     a(2140)     1.0   
     0.000      5.827     25.0     6     a(2140)     1.0   
    34.651      0.000     40.0     1     a(2140)     1.0   
    34.333      0.520     40.0     1     a(2140)     1.0   
    34.020      0.931     40.0     1     a(2140)     1.0   
    34.020      0.931     40.0     4     a(2140)     0.2   
    30.252      1.135     40.0     4     a(2140)     0.2   
    25.729      1.823     40.0     4     a(2140)     0.2   
    25.729      1.823     40.0     5     a(2140)     0.1   
    22.793      2.349     40.0     5     a(2140)     0.1   
    20.278      2.605     40.0     5     a(2140)     0.1   
    20.278      2.605     40.0     6     a(2140)     1.0   
    15.633      3.197     40.0     6     a(2140)     1.0   
    10.455      3.740     40.0     6     a(2140)     1.0   
     7.791      4.273     40.0     6     a(2140)     1.0   
     5.321      4.781     40.0     6     a(2140)     1.0   
     3.493      5.011     40.0     6     a(2140)     1.0   
     0.000      6.142     40.0     6     a(2140)     1.0   
    26.757      0.000     25.0     1     a(2141)     1.0   
    25.292      0.527     25.0     1     a(2141)     0.0   
    25.065      0.936     25.0     1     a(2141)     0.0   
    25.065      0.936     25.0     4     a(2141)     0.2   
    22.638      1.017     25.0     4     a(2141)     0.0   
    21.737      1.380     25.0     4     a(2141)     0.2   
    20.644      1.630     25.0     4     a(2141)     0.2   
    20.644      1.630     25.0     5     a(2141)     0.1   
    19.488      1.790     25.0     5     a(2141)     0.1   
    17.010      2.171     25.0     5     a(2141)     0.1   
    15.572      2.672     25.0     5     a(2141)     0.1   
    15.572      2.672     25.0     6     a(2141)     1.0   
    14.342      2.851     25.0     6     a(2141)     1.0   
     8.796      3.682     25.0     6     a(2141)     1.0   
     3.667      4.815     25.0     6     a(2141)     1.0   
     0.000      5.810     25.0     6     a(2141)     1.0   
    14.729      2.910     25.0     6     a(2142)     1.0   
    14.729      2.910     25.0     5     a(2142)     0.1   
    20.910      1.601     25.0     5     a(2142)     0.1   
    20.898      1.595     25.0     4     a(2142)     0.2   
    21.907      1.420     25.0     4     a(2142)     0.2   
    22.549      1.216     25.0     4     a(2142)     0.2   
    25.104      0.971     25.0     4     a(2142)     0.2   
    25.104      0.971     25.0     1     a(2142)     1.0   
     0.000      5.805     25.0     6         b       0.0       
     2.274      5.252     25.0     6         b       0.0       
     6.109      4.367     25.0     6         b       0.0       
     7.271      4.117     25.0     6         b       0.0       
     8.346      3.913     25.0     6         b       0.0       
     9.482      3.761     25.0     6         b       0.0       
    13.605      3.110     25.0     6         b       0.0       
    14.267      2.989     25.0     6         b       0.0       
    15.242      2.853     25.0     6         b       0.0       
    15.242      2.853     25.0     5         b       0.0       
    15.991      2.619     25.0     5         b       0.0       
    17.091      2.475     25.0     5         b       0.0       
    17.303      2.248     25.0     5         b       0.0       
    18.965      2.021     25.0     5         b       0.0       
    18.965      2.021     25.0     4         b       0.0       
    19.777      1.930     25.0     4         b       0.0       
    19.777      1.930     25.0     5         b       0.0       
    19.777      1.930     25.0     1         b       0.0       
    20.526      1.786     25.0     4         b       0.0       
    20.526      1.786     25.0     5         b       0.0       
    20.526      1.786     25.0     1         b       0.0       
    22.051      1.514     25.0     4         b       0.0       
    22.051      1.514     25.0     5         b       0.0       
    22.051      1.514     25.0     1         b       0.0       
    23.175      1.309     25.0     4         b       0.0       
    23.175      1.309     25.0     5         b       0.0       
    23.175      1.309     25.0     1         b       0.0       
    24.462      1.181     25.0     4         b       0.0       
    24.462      1.181     25.0     5         b       0.0       
    24.462      1.181     25.0     1         b       0.0       
    25.299      1.007     25.0     4         b       0.0       
    25.299      1.007     25.0     1         b       0.0       
    20.327      1.642     25.0     4         b       0.0       
    23.025      1.196     25.0     4         b       0.0       
    25.486      0.817     25.0     1         b       0.0       
    26.111      0.000     25.0     1         b       0.0       
     0.000      6.639     60.0     6         b        -        
     3.508      5.518     60.0     6         b        -        
     6.406      4.868     60.0     6         b        -        
    13.633      3.497     60.0     6         b        -        
    19.805      2.875     60.0     6         b        -        
    25.678      2.537     60.0     6         b        -        
    28.531      2.420     60.0     6         b        -        
    29.975      2.362     60.0     6         b        -        
    29.975      2.362     60.0     5         b        -        
    31.751      2.215     60.0     5         b        -        
    32.861      2.137     60.0     5         b        -        
    33.971      2.087     60.0     5         b        -        
    34.304      1.990     60.0     5         b        -        
    35.415      1.854     60.0     5         b        -        
    35.415      1.854     60.0     4         b        -        
    36.081      1.826     60.0     4         b        -        
    36.525      1.815     60.0     4         b        -        
    38.079      1.671     60.0     4         b        -        
    39.078      1.571     60.0     4         b        -        
    40.965      1.521     60.0     4         b        -        
    43.408      1.382     60.0     4         b        -        
    44.962      1.302     60.0     4         b        -        
    49.847      1.130     60.0     4         b        -        
    49.847      1.130     60.0     1         b        -        
    50.291      0.896     60.0     1         b        -        
    51.401      0.0       60.0     1         b        -    
    4.65        3.03     -21.0     1         c       0.0   
    4.65        3.03     -21.0     6         c       0.0   
    4.65        3.03     -21.0     0         c       0.0

Notes and References

Prefix m denotes molality; t - experimental temperature (^oC); solid - identity of the solid which the solution is saturated with respect to; ref. - source of data; weight - the weight given to the data point in the fit of the model (normalised).
Solids: 0 - ice, 1 - NH4NO3(s), 4 - (NH4)2SO4.3NH4NO3(s), 5 - (NH4)2SO4.2NH4NO3(s), 6 - (NH4)2SO4(s).
Sources: a - H. L. Silcock, Solubilities of Inorganic and Organic Compounds, Vol. 3, Pergamon, Oxford, 1979, (the table numbers are given in parentheses); b - H. H. Emmons and H. Kloth (1968) Wissenschaftl. Zeitschr. 10, 102-106; c - D. Mazzotto (1891) Nuovo Cimento [3] 29, 21-36.

(2) Water Activities from Electrodynamic Balance Measurements

mNH4NO3    m(NH4)2SO4    t        aW      np   ref. weight   
  5.312      5.312     25.0     0.7154    1     d    1.0   
  6.014      6.014     25.0     0.6837    1     d    1.0     
  7.375      7.375     25.0     0.6417    1     d    1.0      
  9.723      9.723     25.0     0.5732    1     d    1.0      
  12.17      12.17     25.0     0.5158    1     d    1.0      
  14.21      14.21     25.0     0.4783    1     d    1.0      
  17.80      17.80     25.0     0.4252    1     d    1.0      
  9.381      9.381     25.0     0.5813    2     d    1.0      
  16.54      16.54     25.0     0.4554    2     d    1.0      
  13.55      13.55     25.0     0.4966    2     d    1.0      
  11.53      11.53     25.0     0.5319    2     d    1.0      
  8.048      8.048     25.0     0.6138    2     d    1.0      
  6.188      6.188     25.0     0.6807    2     d    1.0      
  4.813      4.813     25.0     0.7353    2     d    1.0      
  4.374      4.374     25.0     0.7567    2     d    1.0      
  22.45      22.45     25.0     0.3778    2     d    1.0      
  24.91      24.91     25.0     0.3535    2     d    0.0      
  4.187      4.187     25.0     0.7704    3     d    1.0      
  6.040      6.040     25.0     0.6825    3     d    1.0      
  11.72      11.72     25.0     0.5268    3     d    1.0      
  16.22      16.22     25.0     0.4538    3     d    1.0      
  13.14      13.14     25.0     0.4995    3     d    1.0      
  9.691      9.691     25.0     0.5680    3     d    1.0      
  5.401      5.401     25.0     0.7070    3     d    1.0      
  4.438      4.438     25.0     0.7580    3     d    1.0      
  6.835      6.835     25.0     0.6522    3     d    1.0      
  6.735      3.367     25.0     0.7466    1     d    1.0      
  9.387      4.694     25.0     0.5961    1     d    0.0      
  16.41      8.206     25.0     0.5481    1     d    1.0      
  23.36      11.68     25.0     0.4759    1     d    1.0      
  26.95      13.48     25.0     0.4402    1     d    1.0      
  31.79      15.90     25.0     0.4122    1     d    1.0      
  3.291      1.646     25.0     0.8366    1     d    0.0      
  3.246      1.623     25.0     0.8317    1     d    0.0      
  4.826      2.413     25.0     0.7547    1     d    0.0      
  7.308      3.654     25.0     0.7369    2     d    1.0      
  6.519      3.259     25.0     0.7555    2     d    1.0      
  7.424      3.712     25.0     0.7218    2     d    1.0      
  10.86      5.428     25.0     0.6400    2     d    1.0      
  15.12      7.558     25.0     0.5653    2     d    1.0      
  21.06      10.53     25.0     0.4973    2     d    1.0      
  24.88      12.44     25.0     0.4507    2     d    1.0      
  29.43      14.71     25.0     0.4180    2     d    1.0      
  6.645      3.322     25.0     0.7466    3     d    1.0      
  8.833      4.416     25.0     0.6914    3     d    1.0      
  12.63      6.317     25.0     0.6078    3     d    1.0      
  18.68      9.339     25.0     0.5327    3     d    0.0      
  25.26      12.63     25.0     0.4723    3     d    0.0      
  37.14      18.57     25.0     0.3892    3     d    1.0      
  22.77      11.38     25.0     0.4919    3     d    0.0      
  15.88      7.938     25.0     0.5616    3     d    1.0      
  10.47      5.236     25.0     0.6531    3     d    1.0      
  8.249      4.125     25.0     0.7089    3     d    1.0      
  7.317      3.658     25.0     0.7354    3     d    1.0      
  8.130      2.033     25.0     0.7708    1     d    1.0      
  10.70      2.675     25.0     0.7125    1     d    1.0      
  12.38      3.096     25.0     0.6820    1     d    1.0      
  15.64      3.910     25.0     0.6278    1     d    1.0      
  23.67      5.918     25.0     0.5324    1     d    1.0      
  30.23      7.558     25.0     0.4805    1     d    1.0      
  36.24      9.059     25.0     0.4401    1     d    1.0      
  20.52      5.130     25.0     0.5703    1     d    1.0      
  55.92      13.98     25.0     0.3566    1     d    1.0      
  9.614      2.403     25.0     0.7382    2     d    1.0      
  11.55      2.887     25.0     0.6960    2     d    1.0      
  13.92      3.481     25.0     0.6533    2     d    1.0      
  18.78      4.694     25.0     0.5881    2     d    1.0      
  24.13      6.032     25.0     0.5268    2     d    1.0      
  30.34      7.586     25.0     0.4335    2     d    0.0      
  8.078      2.019     25.0     0.7712    3     d    1.0      
  13.59      3.398     25.0     0.6609    3     d    1.0      
  23.38      5.844     25.0     0.5333    3     d    1.0      
  33.28      8.321     25.0     0.4610    3     d    1.0      
  27.86      6.965     25.0     0.4998    3     d    1.0      
  18.80      4.700     25.0     0.5914    3     d    1.0      
  12.01      3.002     25.0     0.6865    3     d    1.0      
  10.60      2.649     25.0     0.7146    3     d    1.0      
  9.422      2.355     25.0     0.7416    3     d    1.0      
  43.26      10.81     25.0     0.4015    3     d    1.0      
  30.40      7.600     25.0     0.4817    3     d    1.0      
  17.99      4.498     25.0     0.5843    4     d    0.0      
  26.54      6.635     25.0     0.5008    4     d    1.0      
  42.47      10.62     25.0     0.4054    4     d    1.0      
  32.98      8.246     25.0     0.4653    4     d    1.0      
  22.29      5.573     25.0     0.5473    4     d    1.0      
  17.12      4.281     25.0     0.6104    4     d    1.0      
  8.514      2.129     25.0     0.7602    4     d    1.0      
  9.624      2.406     25.0     0.7387    4     d    1.0      
  10.77      2.692     25.0     0.7096    4     d    1.0      
  12.25      3.061     25.0     0.6859    4     d    1.0      
  3.483      6.967     25.0     0.6986    1     d    1.0      
  4.633      9.266     25.0     0.6197    1     d    1.0      
  6.376      12.75     25.0     0.5307    1     d    1.0      
  7.208      14.42     25.0     0.4972    1     d    1.0      
  5.776      11.55     25.0     0.5695    1     d    1.0      
  4.087      8.174     25.0     0.6537    1     d    1.0      
  3.233      6.466     25.0     0.7116    1     d    1.0      
  2.593      5.185     25.0     0.7605    1     d    1.0      
  2.929      5.857     25.0     0.7342    1     d    1.0      
  7.638      15.28     25.0     0.4785    1     d    1.0      
  8.564      17.13     25.0     0.4589    1     d    1.0      
  9.609      19.22     25.0     0.4239    1     d    1.0      
  5.594      11.19     25.0     0.5716    2     d    1.0      
  4.153      8.306     25.0     0.6525    2     d    1.0      
  3.321      6.641     25.0     0.7080    2     d    1.0      
  2.697      5.394     25.0     0.7569    2     d    1.0      
  2.997      5.994     25.0     0.7254    2     d    1.0      
  3.695      7.390     25.0     0.6768    2     d    1.0      
  4.720      9.441     25.0     0.6133    2     d    1.0      
  6.447      12.89     25.0     0.5275    2     d    1.0      
  7.711      15.42     25.0     0.4743    2     d    1.0      
  9.612      19.22     25.0     0.4262    2     d    1.0      
  10.95      21.89     25.0     0.4000    2     d    1.0      
  12.19      24.37     25.0     0.3667    2     d    1.0      
  13.18      26.36     25.0     0.3475    2     d    1.0      
  15.48      30.96     25.0     0.3171    2     d    0.0      
  5.573      11.15     25.0     0.5659    3     d    1.0      
  4.151      8.301     25.0     0.6493    3     d    1.0      
  3.298      6.596     25.0     0.7083    3     d    1.0      
  2.680      5.359     25.0     0.7593    3     d    1.0      
  2.888      5.776     25.0     0.7408    3     d    1.0      
  3.392      6.785     25.0     0.6935    3     d    1.0      
  4.354      8.709     25.0     0.6245    3     d    0.0      
  2.645      5.291     25.0     0.7639    4     d    1.0      
  3.057      6.114     25.0     0.7234    4     d    1.0      
  3.792      7.583     25.0     0.6701    4     d    1.0      
  5.367      10.73     25.0     0.5771    4     d    1.0      
  6.829      13.66     25.0     0.5123    4     d    1.0      
  8.166      16.33     25.0     0.4627    4     d    1.0      
  1.513      4.540     25.0     0.8161    1     d    1.0      
  4.142      12.43     25.0     0.5573    1     d    1.0      
  5.141      15.42     25.0     0.4999    1     d    1.0      
  6.111      18.33     25.0     0.4516    1     d    1.0      
  2.932      8.798     25.0     0.6481    1     d    1.0      
  2.195      6.584     25.0     0.7247    1     d    1.0      
  1.713      5.140     25.0     0.7837    1     d    1.0      
  5.356      16.07     25.0     0.4792    1     d    1.0      
  2.885      8.655     25.0     0.6627    2     d    1.0      
  4.136      12.41     25.0     0.5682    2     d    1.0      
  1.859      5.576     25.0     0.7749    2     d    0.0      
  2.074      6.222     25.0     0.7404    2     d    1.0      
  2.242      6.727     25.0     0.7213    2     d    1.0      
  2.427      7.283     25.0     0.6967    2     d    1.0      
  3.376      10.13     25.0     0.6036    2     d    1.0      
  4.683      14.05     25.0     0.5132    2     d    1.0      
  5.031      15.09     25.0     0.4871    2     d    1.0      
  5.719      17.16     25.0     0.4567    2     d    1.0      
  5.799      17.40     25.0     0.4736    3     d    1.0      
  5.008      15.03     25.0     0.5111    3     d    1.0      
  3.723      11.17     25.0     0.5853    3     d    1.0      
  2.715      8.145     25.0     0.6747    3     d    1.0      
  2.157      6.473     25.0     0.7305    3     d    1.0      
  1.870      5.611     25.0     0.7655    3     d    1.0      
  2.421      7.263     25.0     0.6949    3     d    1.0      
  3.120      9.361     25.0     0.6320    3     d    1.0      
  4.315      12.95     25.0     0.5391    3     d    1.0      
  5.047      15.14     25.0     0.4852    3     d    1.0      
  6.077      18.23     25.0     0.4406    3     d    1.0      
  1.275      6.375     25.0     0.7648    1     d    0.0      
  1.376      6.880     25.0     0.7353    1     d    1.0      
  1.468      7.339     25.0     0.7138    1     d    1.0      
  1.630      8.152     25.0     0.6867    1     d    1.0      
  1.809      9.045     25.0     0.6573    1     d    1.0      
  2.008      10.04     25.0     0.6228    1     d    1.0      
  2.355      11.78     25.0     0.5792    1     d    1.0      
  2.704      13.52     25.0     0.5302    1     d    0.0      
  2.974      14.87     25.0     0.4983    1     d    0.0      
  1.202      6.011     25.0     0.7675    2     d    1.0      
  1.381      6.905     25.0     0.7305    2     d    1.0      
  1.715      8.573     25.0     0.6725    2     d    1.0      
  2.057      10.28     25.0     0.6198    2     d    1.0      
  2.358      11.79     25.0     0.5824    2     d    1.0      
  2.707      13.54     25.0     0.5404    2     d    1.0      
  3.067      15.33     25.0     0.5025    2     d    1.0      
  3.285      16.42     25.0     0.4863    2     d    1.0      
  3.519      17.59     25.0     0.4573    2     d    1.0      
  4.005      20.02     25.0     0.4226    2     d    1.0      
  4.473      22.36     25.0     0.3855    2     d    1.0      
  2.415      12.08     25.0     0.5720    3     d    1.0      
  1.730      8.648     25.0     0.6733    3     d    1.0      
  1.373      6.864     25.0     0.7339    3     d    1.0      
  1.225      6.124     25.0     0.7632    3     d    1.0      
  1.521      7.604     25.0     0.7022    3     d    1.0      
  1.985      9.925     25.0     0.6288    3     d    1.0      
  2.826      14.13     25.0     0.5245    3     d    1.0      
  3.419      17.09     25.0     0.4734    3     d    1.0

Notes and References

Prefix m denotes molality; t - experimental temperature (^oC); aW - water activity; np - particle number; ref. - the source of data; weight - the weight given to the data point in the fit of the model (normalised).
Source: d - C. K. Chan, R. C. Flagan and J. H. Seinfeld (1992) Atmos. Environ. 26A, 1661-1673.

(3) Water Activities from Vapour Pressure Measurements

  mNH4NO3   m(NH4)2SO4      t           aW       ref.   weight     
   0.00        5.82       25.0        0.80135     e      0.0           
   2.28        5.26       25.0        0.76726     e      0.0           
   7.28        4.12       25.0        0.72643     e      0.0           
   9.48        3.76       25.0        0.70034     e      0.0              
  14.28        2.99       25.0        0.66456     e      0.0             
  15.26        2.86       25.0        0.70370     e      0.0           
  17.10        2.48       25.0        0.65572     e      0.0           
  18.96        2.02       25.0        0.65067     e      0.0           
  20.54        1.79       25.0        0.62458     e      0.0           
  25.30        0.00       25.0        0.61490     e      0.0           
   0.00        5.82       30.0        0.80138     e      0.0           
   2.28        5.26       30.0        0.76618     e      0.0           
   7.28        4.12       30.0        0.72313     e      0.0           
   9.48        3.76       30.0        0.69799     e      0.0           
  14.28        2.99       30.0        0.65745     e      0.0             
  15.26        2.86       30.0        0.65556     e      0.0             
  17.10        2.48       30.0        0.64613     e      0.0             
  18.96        2.02       30.0        0.64111     e      0.0             
  20.54        1.79       30.0        0.61439     e      0.0             
  25.30        0.00       30.0        0.61062     e      0.0             
   0.00        5.82       40.0        0.79772     e      0.0             
   2.28        5.26       40.0        0.76699     e      0.0             
   7.28        4.12       40.0        0.71999     e      0.0             
   9.48        3.76       40.0        0.69505     e      0.0             
  14.28        2.99       40.0        0.65040     e      0.0             
  15.26        2.86       40.0        0.65058     e      0.0             
  17.10        2.48       40.0        0.63069     e      0.0             
  18.96        2.02       40.0        0.63142     e      0.0             
  20.54        1.79       40.0        0.59906     e      0.0             
  25.30        0.00       40.0        0.59888     e      0.0             
   0.00        5.82       50.0        0.79581     e      0.0             
   2.28        5.26       50.0        0.76003     e      0.0             
   7.28        4.12       50.0        0.71441     e      0.0             
   9.48        3.76       50.0        0.68576     e      0.0             
  14.28        2.99       50.0        0.64620     e      0.0             
  15.26        2.86       50.0        0.64317     e      0.0             
  17.10        2.48       50.0        0.62253     e      0.0             
  18.96        2.02       50.0        0.62469     e      0.0             
  20.54        1.79       50.0        0.58848     e      0.0             
  25.30        0.00       50.0        0.59053     e      0.0             
   0.00        6.63       55.0        0.80939     e       -              
   3.52        5.52       55.0        0.75517     e       -              
   6.42        4.87       55.0        0.71256     e       -              
  13.66        3.50       55.0        0.65664     e       -              
  19.82        2.88       55.0        0.59514     e       -              
   0.00        5.82       60.0        0.79971     e       -              
   2.28        5.26       60.0        0.76135     e       -              
   7.28        4.12       60.0        0.71040     e       -              
   9.48        3.76       60.0        0.67700     e       -              
  14.28        2.99       60.0        0.64219     e       -              
  15.26        2.86       60.0        0.63991     e       -              
  17.10        2.48       60.0        0.62016     e       -              
  18.96        2.02       60.0        0.61742     e       -              
  20.54        1.79       60.0        0.57926     e       -              
  25.30        0.00       60.0        0.57893     e       -              
   0.00        6.63       60.0        0.80352     e       -              
   3.52        5.52       60.0        0.75010     e       -              
   6.42        4.87       60.0        0.71067     e       -              
  13.66        3.50       60.0        0.65116     e       -              
  19.82        2.88       60.0        0.59205     e       -              
   0.00        5.82       65.0        0.63698     e       -              
   2.28        5.26       65.0        0.60643     e       -              
   7.28        4.12       65.0        0.56585     e       -              
   9.48        3.76       65.0        0.53924     e       -              
  14.28        2.99       65.0        0.51152     e       -              
  15.26        2.86       65.0        0.50970     e       -              
  17.10        2.48       65.0        0.49397     e       -              
  18.96        2.02       65.0        0.49179     e       -              
  20.54        1.79       65.0        0.46139     e       -              
  25.30        0.00       65.0        0.46113     e       -              
   0.00        6.63       65.0        0.64002     e       -              
   3.52        5.52       65.0        0.59747     e       -              
   6.42        4.87       65.0        0.56607     e       -              
  13.66        3.50       65.0        0.51866     e       -              
  19.82        2.88       65.0        0.47158     e       -              
   0.00        5.82       70.0        0.51108     e       -              
   2.28        5.26       70.0        0.48657     e       -              
   7.28        4.12       70.0        0.45401     e       -              
   9.48        3.76       70.0        0.43266     e       -              
  14.28        2.99       70.0        0.41041     e       -              
  15.26        2.86       70.0        0.40896     e       -              
  17.10        2.48       70.0        0.39634     e       -              
  18.96        2.02       70.0        0.39458     e       -              
  20.54        1.79       70.0        0.37020     e       -              
  25.30        0.00       70.0        0.36998     e       -              
   0.00        6.63       70.0        0.51352     e       -              
   3.52        5.52       70.0        0.47938     e       -    
   6.42        4.87       70.0        0.45418     e       -    
  13.66        3.50       70.0        0.41615     e       -    
  19.82        2.88       70.0        0.37837     e       -

Notes and References

Prefix m denotes molality; aW - solution water activity; ref. - source of data; weight - the weight given to the data point in the fit of the model (normalised).
These data were used for comparison only, and were not included in the fit of the activity coefficient model parameters.
Source: e - H. H. Emmons and W. Hahn (1970) Wissenschaftl. Zeitschr. 12, 129-132.

Model II: Data for Aqueous NH4+ - SO42− - NO3−

The System

Weights

The Data

(1) Solubilities of Solid Phases

(2) Water Activities from Electrodynamic Balance Measurements

(3) Water Activities from Vapour Pressure Measurements

Model II: Data for Aqueous NH₄⁺ - SO₄²⁻ - NO₃⁻