Aqueous H₂SO₄: Heat Capacities (Including Solid Hydrates)

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

A new study of the heat capacity of pure water at very low temperature has been made by Murphy and Koop (2005) since the work of Clegg and Brimblecombe (1995):

• D. M. Murphy and T. Koop (2005) Q. J. R. Meteorol. Soc. 131, 1539–1565.

See Murphy and Koop for a comparison of their values of the heat capacity with those assumed by Clegg and Brimblecombe (1995), which are used to obtain apparent molar heat capacities of sulphuric acid from the measurements for aqueous solutions listed here.

1.  Heat Capacities of Solid Sulphuric Acid

  T(orig.)   Cp(orig.)   ΔT     error   T(corr.)   Cp(corr.)  series  ref.        
    16.11     0.930     1.770    3.00    16.109      0.930      1      a
    18.91     1.470     2.820    3.00    18.909      1.470      1      a
    22.28     2.070     3.450    1.00    22.279      2.070      1      a
    25.34     2.610     2.620    1.00    25.339      2.610      1      a
    27.52     3.000     2.220    0.50    27.519      3.000      1      a
    30.65     3.600     3.750    0.50    30.649      3.600      1      a
    34.08     4.250     3.100    0.50    34.079      4.250      1      a
    37.33     4.740     3.340    0.20    37.329      4.740      1      a
    40.74     5.270     3.330    0.20    40.739      5.270      1      a
    44.43     5.800     3.980    0.20    44.428      5.800      1      a
    48.69     6.390     4.540    0.20    48.688      6.390      1      a
    53.44     6.980     5.020    0.20    53.438      6.980      1      a
    58.64     7.570     5.420    0.20    58.638      7.570      1      a
    63.80     8.070     4.860    0.20    63.798      8.070      1      a
    68.49     8.580     4.450    0.20    68.488      8.580      1      a
    73.21     8.940     4.980    0.20    73.207      8.940      1      a
    78.01     9.250     4.640    0.20    78.007      9.250      1      a
    83.28     9.630     5.950    0.20    83.277      9.630      1      a
    84.20     9.670     5.870    0.20    84.197      9.670      1      a
    90.32    10.010     6.280    0.20    90.317     10.010      1      a
    96.27    10.490     5.850    0.20    96.267     10.490      1      a
   102.29    10.940     6.230    0.20   102.286     10.940      1      a
   108.36    11.370     5.860    0.20   108.356     11.370      1      a
   114.47    11.770     6.230    0.20   114.466     11.770      1      a
   120.59    12.220     5.890    0.20   120.586     12.220      1      a
   127.04    12.650     6.950    0.20   127.035     12.650      1      a
   133.82    13.110     6.470    0.20   133.815     13.110      1      a
   140.45    13.560     6.890    0.20   140.445     13.560      1      a
   147.45    14.030     7.190    0.20   147.445     14.031      1      a
   154.41    14.500     6.830    0.20   154.404     14.501      1      a
   161.05    15.030     6.460    0.20   161.044     15.031      1      a
   167.65    15.530     6.830    0.20   167.644     15.531      1      a
   174.56    15.850     7.110    0.20   174.554     15.851      1      a
   181.42    16.350     6.750    0.20   181.413     16.351      1      a
   188.28    16.850     7.020    0.20   188.273     16.851      1      a
   195.15    17.270     6.720    0.20   195.143     17.271      1      a
   201.72    17.740     6.430    0.20   201.713     17.741      1      a
   207.87    18.140     7.250    0.20   207.862     18.141      1      a
   214.61    18.620     6.970    0.20   214.602     18.621      1      a
   222.16    19.110     8.330    0.20   222.152     19.111      1      a
   228.23    19.400     8.050    0.20   228.222     19.401      1      a
   235.88    20.010     7.650    0.20   235.871     20.011      1      a
   230.64    19.620     7.980    0.20   230.632     19.621      2      a
   239.05    20.170     8.780    0.20   239.041     20.171      2      a
   247.63    20.720     8.350    0.20   247.621     20.721      2      a
   255.71    21.720     7.850    0.20   255.701     21.721      2      a
   263.47    23.680     7.870    0.20   263.460     23.681      2      a
   268.99    22.880     8.020    0.20   268.980     22.881      2      a
   287.66    32.630     4.780    0.20   287.650     32.631      2      a
   293.00    32.720     6.930    0.20   292.989     32.721      2      a
   299.22    33.250     6.670    0.20   299.209     33.251      2      a
   305.67    33.540     6.890    0.20   305.659     33.541      2      a
   238.27    20.120     4.470    0.20   238.261     20.121      3      a
   242.86    20.490     4.660    0.20   242.851     20.491      3      a
   247.51    20.820     4.560    0.20   247.501     20.821      3      a
   251.99    21.060     4.450    0.20   251.981     21.061      3      a
   254.73    21.730     6.150    0.20   254.721     21.731      4      a
   259.55    22.470     3.540    0.20   259.540     22.471      4      a
   261.79    24.360     1.580    0.20   261.780     24.361      4      a
   263.38    23.320     1.600    0.20   263.370     23.321      4      a
   265.04    22.560     1.630    0.20   265.030     22.561      4      a
   269.59    23.030     5.470    0.20   269.580     23.031      4      a
   275.23    24.680     5.120    0.20   275.220     24.681      4      a
   279.78    34.080     3.910    0.20   279.770     34.081      4      a

Notes and References

• Key: T(orig .) - experimental temperatures (K) listed in Table II of Rubin and Giauque (1952), based upon 0 ^oC = 273.16 K; Cp(orig.) - experimental heat capacities (cal mol^-1 K^-1) listed in Table II Rubin and Giauque (1952), based upon 0 ^oC = 273.16 K; ΔT - temperature difference over which the heat capacity was measured; T(corr .) and Cp(corr.) - temperatures and heat capacities corrected to 0 ^oC = 273.15 K (T(orig .) is multiplied by 273.15/273.16, and Cp(orig.) is multiplied by 273.16/273.15); error - estimated percentage error in Cp; ref. - source of data.
• The defined calorie of Rubin and Giauque is equal to 4.184 J.
• Source: a - T. R. Rubin and W. F. Giauque (1952) J. Amer. Chem. Soc. 74, 800-804.
• H2SO4(s) melts at a temperature of 283.46 K (W. F. Giauque et al. (1960) J. Amer. Chem. Soc. 82, 62-70), thus all the heat capacities in this table are for the solid acid. Rubin and Giauque (1952) also list melting points, heats of fusion, and entropies of the acid, and its mono- and dihydrates. Tabulations of smoothed values of heat capacities of H2SO4(s,l) are given by Giauque et al. (1960) in their evaluation of the thermodynamic properties of aqueous sulphuric acid and its hydrates.

2.  Heat Capacities of Sulphuric Acid Monohydrate (Solid and Liquid)

T(orig .)  Cp(orig.)   ΔT      error  T(corr .)  Cp(corr.)  series  ref. 
  14.87     0.570     1.29      3.00   14.869     0.5700      1      a
  16.62     0.750     2.09      3.00   16.619     0.7500      1      a
  18.65     1.04      1.95      3.00   18.649     1.0400      1      a
  20.81     1.41      2.40      1.00   20.809     1.4101      1      a
  23.43     1.85      2.93      1.00   23.429     1.8501      1      a
  26.11     2.29      2.41      1.00   26.109     2.2901      1      a
  28.94     2.81      3.18      1.00   28.939     2.8101      1      a
  32.30     3.47      3.43      1.00   32.299     3.4701      1      a
  35.93     4.20      3.73      0.20   35.929     4.2002      1      a
  39.83     4.91      4.01      0.20   39.829     4.9102      1      a
  43.98     5.61      4.28      0.20   43.978     5.6102      1      a
  48.50     6.37      4.83      0.20   48.498     6.3702      1      a
  53.45     7.20      5.12      0.20   53.448     7.2003      1      a
  58.49     8.00      4.99      0.20   58.488     8.0003      1      a
  63.46     8.73      4.90      0.20   63.458     8.7303      1      a
  68.38     9.39      4.89      0.20   68.378     9.3903      1      a
  73.57    10.04      5.50      0.20   73.567    10.0404      1      a
  78.83    10.66      5.03      0.20   78.827    10.6604      1      a
  84.22    11.26      5.76      0.20   84.217    11.2604      1      a
  89.84    11.82      5.62      0.20   89.837    11.8204      1      a
  95.61    12.44      5.89      0.20   95.607    12.4405      1      a
 101.66    13.10      6.16      0.20  101.656    13.1005      1      a
 107.95    13.75      6.41      0.20  107.946    13.7505      1      a
 114.47    14.42      6.63      0.20  114.466    14.4205      1      a
 121.19    15.07      6.85      0.20  121.186    15.0706      1      a
 128.13    15.71      7.02      0.20  128.125    15.7106      1      a
 134.87    16.32      6.58      0.20  134.865    16.3206      1      a
 141.20    16.90      6.19      0.20  141.195    16.9006      1      a
 147.51    17.41      6.41      0.20  147.505    17.4106      1      a
 153.86    18.00      6.08      0.20  153.854    18.0007      1      a
 159.82    18.51      5.81      0.20  159.814    18.5107      1      a
 165.71    19.12      6.03      0.20  165.704    19.1207      1      a
 171.95    19.66      6.47      0.20  171.944    19.6607      1      a
 178.50    20.20      6.67      0.20  178.493    20.2007      1      a
 185.01    20.83      6.36      0.20  185.003    20.8308      1      a
 191.50    21.44      6.56      0.20  191.493    21.4408      1      a
 198.26    22.06      6.97      0.20  198.253    22.0608      1      a
 205.14    22.68      6.66      0.20  205.133    22.6808      1      a
 211.73    23.21      6.39      0.20  211.722    23.2108      1      a
 218.03    23.68      6.18      0.20  218.022    23.6809      1      a
 224.86    24.52      7.13      0.20  224.852    24.5209      1      a
 231.74    26.58      6.50      0.20  231.732    26.5810      1      a
 238.36    25.67      6.53      0.20  238.351    25.6709      1      a
 244.89    26.27      6.28      0.20  244.881    26.2710      1      a
 251.34    27.02      6.55      0.20  251.331    27.0210      1      a
 257.97    27.60      6.79      0.20  257.961    27.6010      1      a
 264.74    28.49      6.95      0.20  264.730    28.4910      1      a
 271.55    30.21      6.90      0.20  271.540    30.2111      1      a
 218.11    23.84      6.55      0.20  218.102    23.8409      2      a
 224.89    24.51      7.03      0.20  224.882    24.5109      2      a
 229.25    24.86      3.42      0.20  229.242    24.8609      2      a
 233.08    25.19      3.36      0.20  233.072    25.1909      2      a
 236.39    25.49      3.29      0.20  236.381    25.4909      2      a
 268.24    29.45      8.02      0.20  268.230    29.4511      3      a
 275.70    31.90      7.14      0.20  275.690    31.9012      3(s)   a
 284.02    50.81      5.92      0.20  284.010    50.8119      4(l)   a
 290.47    51.03      6.95      0.20  290.459    51.0319      4      a
 297.52    51.27      7.18      0.20  297.509    51.2719      4      a
 304.60    51.68      6.94      0.20  304.589    51.6819      4      a

Notes and References

• Key: T(orig .) - experimental temperatures (K) listed in Table III of Rubin and Giauque (1952), based upon 0 ^oC = 273.16 K; Cp(orig.) - experimental heat capacities (cal mol^-1 K^-1) listed in Table III of Rubin and Giauque (1952), based upon 0 ^oC = 273.16 K; ΔT - temperature difference over which the heat capacity was measured; T(corr .) and Cp(corr.) - temperatures and heat capacities corrected to 0 ^oC = 273.15 K (T(orig .) is multiplied by 273.15/273.16, and Cp(orig.) is multiplied by 273.16/273.15); error - estimated percentage error in Cp; ref. - source of data.
• The defined calorie of Rubin and Giauque is equal to 4.184 J.
• Source: a - T. R. Rubin and W. F. Giauque (1952) J. Amer. Chem. Soc. 74, 800-804.
• H2SO4 · H2O (s) melts at a temperature of 281.63 K (W. F. Giauque et al. (1960) J. Amer. Chem. Soc. 82, 62-70). The last measurement on the solid (s) and the first measurement on the liquid mixture of the same composition (l) are noted in the series column. Rubin and Giauque (1952) also list melting points, heats of fusion, and entropies of the acid, and its mono- and dihydrates. Tabulations of smoothed values of heat capacities of H2SO4 · H2O (s,l) are given by Giauque et al. (1960) in their evaluation of the thermodynamic properties of aqueous sulphuric acid and its hydrates.

3.  Heat Capacities of Sulphuric Acid Dihydrate (Solid and Liquid)

 T(orig .)  Cp(orig.)   ΔT      error  T(corr .)  Cp(corr.)  series  ref.  
   14.34     0.920     1.00     0.20    14.340     0.9200      1      a
   16.00     1.20      1.82     0.20    15.999     1.2000      1      a
   17.92     1.67      1.77     0.20    17.919     1.6701      1      a
   19.99     2.19      2.24     0.20    19.989     2.1901      1      a
   22.58     2.78      2.83     0.20    22.579     2.7801      1      a
   25.26     3.36      2.40     0.20    25.259     3.3601      1      a
   28.39     4.04      3.85     0.20    28.389     4.0401      1      a
   32.04     4.88      3.46     0.20    32.039     4.8802      1      a
   35.73     5.66      3.92     0.20    35.729     5.6602      1      a
   39.31     6.39      3.35     0.20    39.309     6.3902      1      a
   42.88     7.06      3.81     0.20    42.878     7.0603      1      a
   46.89     7.93      4.15     0.20    46.888     7.9303      1      a
   51.51     8.67      4.86     0.20    51.508     8.6703      1      a
   56.61     9.57      5.20     0.20    56.608     9.5704      1      a
   62.08    10.50      5.13     0.20    62.078    10.5004      1      a
   67.26    11.32      5.11     0.20    67.258    11.3204      1      a
   72.16    12.07      4.67     0.20    72.157    12.0704      1      a
   77.28    12.77      5.52     0.20    77.277    12.7705      1      a
   82.54    13.51      5.05     0.20    82.537    13.5105      1      a
   87.94    14.22      5.62     0.20    87.937    14.2205      1      a
   93.36    14.94      5.21     0.20    93.357    14.9405      1      a
   98.79    15.62      5.59     0.20    98.786    15.6206      1      a
  104.51    16.39      5.85     0.20   104.506    16.3906      1      a
  110.22    17.10      5.49     0.20   110.216    17.1006      1      a
  115.85    17.79      5.74     0.20   115.846    17.7907      1      a
  122.19    18.54      6.89     0.20   122.186    18.5407      1      a
  128.84    19.31      6.46     0.20   128.835    19.3107      1      a
  135.49    20.04      6.78     0.20   135.485    20.0407      1      a
  142.07    20.75      6.37     0.20   142.065    20.7508      1      a
  148.68    21.48      6.68     0.20   148.675    21.4808      1      a
  155.54    22.27      6.99     0.20   155.534    22.2708      1      a
  162.77    22.97      7.28     0.20   162.764    22.9708      1      a
  169.86    23.75      6.90     0.20   169.854    23.7509      1      a
  177.60    24.61      7.78     0.20   177.594    24.6109      1      a
  185.16    25.50      7.38     0.20   185.153    25.5009      1      a
  192.88    26.39      7.56     0.20   192.873    26.3910      1      a
  200.24    27.19      7.20     0.20   200.233    27.1910      1      a
  207.21    27.85      7.46     0.20   207.202    27.8510      1      a
  214.49    28.72      7.12     0.20   214.482    28.7211      1      a
  220.81    29.61      5.44     0.20   220.802    29.6111      1      a
  226.49    30.52      5.21     0.20   226.482    30.5211      1(s)   a
  238.71    59.45      4.47     0.20   238.701    59.4522      2(l)   a
  243.48    59.82      5.02     0.20   243.471    59.8222      2      a
  248.95    59.84      5.78     0.20   248.941    59.8422      2      a
  255.16    60.19      6.52     0.20   255.151    60.1922      2      a
  262.63    60.60      7.34     0.20   262.620    60.6022      2      a
  269.65    60.97      7.17     0.20   269.640    60.9722      2      a
  273.53    60.94      4.89     0.20   273.520    60.9422      3      a
  279.01    61.23      6.12     0.20   279.000    61.2322      3      a
  285.20    61.47      6.50     0.20   285.190    61.4723      3      a
  291.83    61.95      6.80     0.20   291.819    61.9523      3      a
  298.75    62.40      7.60     0.20   298.739    62.4023      3      a
  306.14    63.10      7.80     0.20   306.129    63.1023      3      a

Notes and References

• T(orig .) - experimental temperatures (K) listed in Table IV of Rubin and Giauque (1952), based upon 0 ^oC = 273.15 K; Cp(orig.) - experimental heat capacities (cal mol^-1 K^-1) listed in Table IV of Rubin and Giauque (1952), based upon 0 ^oC = 273.16 K; ΔT - temperature difference over which the heat capacity was measured; T(corr .) and Cp(corr.) - temperatures and heat capacities corrected to 0 ^oC = 273.15 K (T(orig .) is multiplied by 273.15/273.16, and Cp(orig.) is multiplied by 273.16/273.15); error - estimated percentage error in Cp; ref. - source of data.
• The defined calorie of Rubin and Giauque is equal to 4.184 J.
• Source: a - T. R. Rubin and W. F. Giauque (1952) J. Amer. Chem. Soc. 74, 800-804.
• Rubin and Giauque (1952) note that corrections (not exceeding 0.2%) needed to be made to results for the dihydrate, but are not given in this paper. They are present in the tabulations of smoothed values given by Giauque et al. (1960), listed further below.
• H2SO4 · 2H2O(s) melts at a temperature of 233.68 K (W. F. Giauque et al. (1960) J. Amer. Chem. Soc. 82, 62-70). The last measurement on the solid (s) and the first measurement on the liquid mixture of the same composition (l) are noted in the series column. Rubin and Giauque (1952) also list melting points, heats of fusion, and entropies of the acid, and its mono- and dihydrates. Tabulations of smoothed values of heat capacities of H2SO4 · 2H2O (s,l) are given by Giauque et al. (1960), including minor corrections to the heat capacities of the solid, in their evaluation of the thermodynamic properties of aqueous sulphuric acid and its hydrates.

4.  Heat Capacities of Sulphuric Acid Trihydrate (Solid and Liquid)

 T(orig .)  Cp(orig.)  ΔT      error  T(corr .)  Cp(corr.) series  state  ref. 
  15.32     1.27      1.40     3.00    15.319     1.2700     1       s     a
  17.41     1.78      2.40     3.00    17.409     1.7801     1       s     a
  19.52     2.31      2.20     3.00    19.519     2.3101     1       s     a
  22.57     3.11      2.30     1.00    22.569     3.1101     1       s     a
  25.76     3.96      3.60     1.00    25.759     3.9601     1       s     a
  29.23     4.80      3.30     1.00    29.229     4.8002     1       s     a
  30.87     5.30      3.30     1.00    30.869     5.3002     1       s     a
  34.98     6.41      4.80     1.00    34.979     6.4102     1       s     a
  39.83     7.71      4.70     0.20    39.829     7.7103     1       s     a
  44.56     8.91      4.60     0.20    44.558     8.9103     1       s     a
  49.34    10.01      4.90     0.20    49.338    10.0104     1       s     a
  54.24    11.20      4.80     0.20    54.238    11.2004     1       s     a
  58.78    12.24      4.30     0.20    58.778    12.2404     1       s     a
  62.98    13.23      4.30     0.20    62.978    13.2305     1       s     a
  67.12    14.07      3.90     0.20    67.117    14.0705     1       s     a
  71.18    14.91      4.20     0.20    71.177    14.9105     1       s     a
  75.39    15.73      4.30     0.20    75.387    15.7306     1       s     a
  80.93    16.71      6.90     0.20    80.927    16.7106     1       s     a
  87.57    17.87      6.40     0.20    87.567    17.8707     1       s     a
  94.10    18.91      6.80     0.20    94.097    18.9107     1       s     a
 100.70    19.97      6.40     0.20   100.696    19.9707     1       s     a
 107.20    20.97      6.60     0.20   107.196    20.9708     1       s     a
 114.14    21.99      7.30     0.20   114.136    21.9908     1       s     a
 121.16    23.03      6.60     0.20   121.156    23.0308     1       s     a
 127.83    24.08      6.70     0.20   127.825    24.0809     1       s     a
 134.64    25.01      7.10     0.20   134.635    25.0109     1       s     a
 142.10    26.03      7.60     0.20   142.095    26.0310     1       s     a
 149.70    27.26      7.60     0.20   149.695    27.2610     1       s     a
 157.67    28.32      8.20     0.20   157.664    28.3210     1       s     a
 166.02    29.60      8.60     0.20   166.014    29.6011     1       s     a
 170.35    30.43      8.10     0.20   170.344    30.4311     1       s     a
 178.93    31.77      8.50     0.20   178.923    31.7712     1       s     a
 187.47    33.20      8.30     0.20   187.463    33.2012     1       s     a
 195.68    34.62      8.10     0.20   195.673    34.6213     1       s     a
 204.61    35.73      9.00     0.20   204.603    35.7313     1       s     a
 212.83    38.85      7.70     0.20   212.822    38.8514     1       s     a
 222.84    38.20      7.60     0.20   222.832    38.2014     1       s     a
 229.45    59.63      5.70     0.20   229.442    59.6322     1       s     a
 232.96    57.82      2.00     0.20   232.952    57.8221     1       s     a
 176.23    31.13      8.10     0.20   176.224    31.1311     2       s     a
 184.61    32.46      8.40     0.20   184.603    32.4612     2       s     a
 193.08    33.83      8.70     0.20   193.073    33.8312     2       s     a
 204.95    35.48     11.80     0.20   204.943    35.4813     2       s     a
 215.49    37.67      8.90     0.20   215.482    37.6714     2       s     a
 224.29    39.50      9.00     0.20   224.282    39.5014     2       s     a
 229.19    41.57      2.50     0.20   229.182    41.5715     2       s     a
 232.71    42.08      2.50     0.20   232.702    42.0815     2       s     a
 235.09    49.95      2.20     0.20   235.081    49.9518     2       s     a
 197.49    34.33      7.40     0.20   197.483    34.3313     3       s     a
 203.32    35.17      6.10     0.20   203.313    35.1713     3       s     a
 210.26    36.06      7.60     0.20   210.252    36.0613     3       s     a
 217.95    39.09      7.60     0.20   217.942    39.0914     3       s     a
 224.82    39.14      6.10     0.20   224.812    39.1414     3       s     a
 229.05    40.52      2.40     0.20   229.042    40.5215     3       s     a
 231.69    42.14      3.00     0.20   231.682    42.1415     3       s     a
 234.52    49.92      2.60     0.20   234.511    49.9218     3       s     a
 210.33    73.76     10.50     0.20   210.322    73.7627     3       s     a
 220.53    74.06     10.00     0.20   220.522    74.0627     3       s     a
 229.64    74.01      7.70     0.20   229.632    74.0127     3       s     a
 237.25    74.08      7.50     0.20   237.241    74.0827     3       s     a
 244.43    74.35      8.00     0.20   244.421    74.3527     4       s     a
 252.99    74.58      8.50     0.20   252.981    74.5827     4       s     a
 261.39    74.81      8.20     0.20   261.380    74.8127     4       s     a
 270.31    75.20      8.50     0.20   270.300    75.2028     4       s     a
 278.83    75.51      8.00     0.20   278.820    75.5128     4       s     a
 287.87    75.96      9.20     0.20   287.860    75.9628     4       s     a
 297.62    76.60      9.50     0.20   297.609    76.6028     4       s     a
 161.77    73.18      3.9      0.20                          1(I)    gl    a
 166.23    73.47      5.1      0.20                          1(I)    gl    a
 171.65    73.61      5.7      0.20                          1(I)    gl    a
 177.28    73.77      5.5      0.20                          1(I)    gl    a
 181.74    73.94      5.9      0.20                          2(I)    l     a
 210.33    73.76     10.5      0.20                          3(I)    l     a
 220.53    74.76     10.0      0.20                          3(I)    l     a
 229.64    74.01      7.7      0.20                          3(I)    l     a
 237.25    74.08      7.5      0.20                          3(I)    l     a
 244.43    74.35      8.0      0.20                          3(I)    l     a
 252.99    74.58      8.5      0.20                          3(I)    l     a
 261.39    74.81      8.2      0.20                          3(I)    l     a
 270.31    75.20      8.5      0.20                          3(I)    l     a
 278.83    75.51      8.0      0.20                          3(I)    l     a
 287.87    75.96      9.2      0.20                          3(I)    l     a
 297.62    76.60      9.5      0.20                          3(I)    l     a

Notes and References

• Key: T(orig .) - experimental temperatures (K) listed in Tables I and II of Kunzler and Giauque (1952), based upon 0 ^oC = 273.16 K; Cp(orig.) - experimental heat capacities (cal mol^-1 K^-1) listed in Tables I and II of Kunzler and Giauque (1952), based upon 0 ^oC = 273.16 K; ΔT - temperature difference over which the heat capacity was measured; T(corr .) and Cp(corr.) - temperatures and heat capacities corrected to 0 ^oC = 273.15 K (T(orig .) is multiplied by 273.15/273.16, and Cp(orig.) is multiplied by 273.16/273.15); error - estimated percentage error in Cp, which is not listed in this paper and is assumed to be the same as in other similar experiments from the same laboratory; series - values marked (I) are from Table I of Kunzler and Giauque (1952) (omitting many of the lower temperature series 1 data), otherwise they are from Table II; state - s (solid), gl (glass), l (liquid or supercooled liquid); ref. - source of data.
• The defined calorie of Kunzler and Giauque is equal to 4.184 J.
• Source: a - J. E. Kunzler and W. F. Giauque (1952) J. Amer. Chem. Soc. 74, 797-800.
• Solid H2SO4 · 3H2O melts at a temperature of 236.76 K (W. F. Giauque et al. (1960) J. Amer. Chem. Soc. 82, 62-70). Kunzler and Giauque (1952) also present values of entropies and a heat of fusion at the transition temperature to solid H2SO4 · 4H2O + liquid. Tabulations of smoothed values of heat capacities of H2SO4 · 3H2O (s,l) are given by Giauque et al. (1960) in their evaluation of the thermodynamic properties of aqueous sulphuric acid and its hydrates.

5.  Heat Capacities of Sulphuric Acid Trihydrate (Solid and Liquid)

T(orig .)  Cp(orig.)   ΔT      error  T(corr .)  Cp(corr.)   ref. 
  14.36     0.990     2.34     3.00    14.360     0.9900      a                                                                            
  17.12     1.63      2.53     3.00    17.119     1.6301      a                                                                            
  19.79     2.32      2.48     3.00    19.789     2.3201      a                                                                            
  22.69     3.10      3.15     1.00    22.689     3.1001      a                                                                            
  25.98     4.00      3.46     1.00    25.979     4.0001      a                                                                            
  29.62     4.98      3.89     1.00    29.619     4.9802      a                                                                            
  33.96     6.14      4.52     1.00    33.959     6.1402      a                                                                            
  38.55     7.30      4.58     0.20    38.549     7.3003      a                                                                            
  43.34     8.52      5.01     0.20    43.338     8.5203      a                                                                            
  48.78     9.85      5.88     0.20    48.778     9.8504      a                                                                            
  54.52    11.17      5.66     0.20    54.518    11.1704      a                                                                            
  60.33    12.50      5.89     0.20    60.328    12.5005      a                                                                            
  66.72    13.91      6.87     0.20    66.718    13.9105      a                                                                            
  74.37    15.45      8.49     0.20    74.367    15.4506      a                                                                            
  81.98    16.88      6.82     0.20    81.977    16.8806      a                                                                            
  88.45    17.89      6.16     0.20    88.447    17.8907      a                                                                            
  94.82    18.94      6.62     0.20    94.816    18.9407      a                                                                            
 101.45    19.99      6.61     0.20   101.446    19.9907      a                                                                            
 108.31    21.06      7.05     0.20   108.306    21.0608      a                                                                            
 115.40    22.15      7.12     0.20   115.396    22.1508      a                                                                            
 122.57    23.23      7.22     0.20   122.566    23.2309      a                                                                            
 129.82    24.30      7.30     0.20   129.815    24.3009      a                                                                            
 137.12    25.33      7.26     0.20   137.115    25.3309      a                                                                            
 144.58    26.40      7.33     0.20   144.575    26.4010      a                                                                            
 152.15    27.50      7.44     0.20   152.144    27.5010      a                                                                            
 159.42    28.55      6.97     0.20   159.414    28.5510      a                                                                            
 166.60    29.61      7.13     0.20   166.594    29.6111      a                                                                            
 173.54    30.65      6.74     0.20   173.534    30.6511      a                                                                            
 180.42    31.66      6.92     0.20   180.413    31.6612      a                                                                            
 187.44    32.77      7.06     0.20   187.433    32.7712      a                                                                            
 194.48    33.84      6.72     0.20   194.473    33.8412      a                                                                            
 201.69    35.01      7.33     0.20   201.683    35.0113      a                                                                            
 209.01    36.28      6.96     0.20   209.002    36.2813      a                                                                            
 215.75    37.36      6.13     0.20   215.742    37.3614      a                                                                            
 220.86    38.47      3.93     0.20   220.852    38.4714      a                                                                            
 225.56    39.02      5.23     0.20   225.552    39.0214      a                                                                            
 229.74    57.81      3.11     0.20   229.732    57.8121      a                                                                            
 233.18    53.11      3.65     0.20   233.172    53.1119      a                                                                            
 244.31    74.54      6.72     0.20   244.301    74.5427      a                                                                            
 251.48    74.64      7.49     0.20   251.471    74.6427      a                                                                            
 258.93    74.83      7.29     0.20   258.921    74.8327      a                                                                            
 266.52    74.90      7.56     0.20   266.510    74.9027      a                                                                            
 274.09    75.11      7.37     0.20   274.080    75.1127      a                                                                            
 281.52    75.48      7.18     0.20   281.510    75.4828      a                                                                            
 288.94    75.66      7.41     0.20   288.929    75.6628      a                                                                            
 296.42    76.21      7.29     0.20   296.409    76.2128      a                                                                            

Notes and References

• Key: T(orig .) - experimental temperatures (K) listed in Table IV of Hornung and Giauque (1955), based upon 0 ^oC = 273.16 K; Cp(orig.) - experimental heat capacities (cal mol^-1 K^-1) listed in Table IV of Hornung and Giauque (1955), based upon 0 ^oC = 273.16 K, and defining 1 calorie as equal to 4.1833 international joules; ΔT - temperature difference over which the heat capacity was measured; T(corr .) and Cp(corr.) - temperatures and heat capacities corrected to 0 ^oC = 273.15 K (T(orig .) is multiplied by 273.15/273.16, and Cp(orig.) is multiplied by 273.16/273.15); error - estimated percentage error in smoothed values of Cp, see note below; ref. - source of data.
• The defined calorie of Kunzler and Giauque is equal to 4.184 J.
• Source: a - E. W. Hornung and W. F. Giauque (1955) J. Amer. Chem. Soc. 77, 2983-2987.
• Solid H2SO4 · 3H2O melts to form a very small amount of tetrahydrate and equilibrium solution at 236.72 K (on the same temperature scale as T(orig .)). The unstable melting point - to the liquid - is estimated to be at 236.77 K on the same scale. Measurements from about 220 K to the melting point include heat effects due to eutectic fusion and pre-melting. The data are corrected for this in the tables of smoothed values of heat capacities presented by Giauque et al. (W. F. Giauque et al. (1960) J. Amer. Chem. Soc. 82, 62-70).

6.  Heat Capacities of Sulphuric Acid Tetrahydrate (H2SO4 · 3.999H2O) (Solid and Liquid)

T(orig .)  Cp(orig.)   ΔT      error  T(corr .)  Cp(corr.)  series  ref. 
  14.90     1.84      1.71     3.00    14.900     1.8401      1      a 
  16.84     2.46      1.39     3.00    16.839     2.4601      1      a
  18.92     3.15      2.02     3.00    18.919     3.1501      1      a
  21.36     3.95      2.41     1.00    21.359     3.9501      1      a
  24.39     5.07      3.24     1.00    24.389     5.0702      1      a
  27.72     6.22      3.32     1.00    27.719     6.2202      1      a
  31.42     7.50      3.90     1.00    31.419     7.5003      1      a
  35.38     8.80      3.78     0.20    35.379     8.8003      1      a
  39.91    10.20      5.14     0.20    39.909    10.2004      1      a
  45.03    11.75      5.15     0.20    45.028    11.7504      1      a
  50.71    13.40      6.16     0.20    50.708    13.4005      1      a
  56.96    15.04      6.33     0.20    56.958    15.0406      1      a
  63.29    16.56      6.22     0.10    63.288    16.5606      1      a
  69.93    18.04      7.03     0.10    69.927    18.0407      1      a
  76.69    19.41      6.47     0.10    76.687    19.4107      1      a
  83.44    20.64      7.00     0.10    83.437    20.6408      1      a
  90.36    21.87      6.83     0.10    90.357    21.8708      1      a
  97.21    23.07      6.84     0.10    97.206    23.0708      1      a
 103.99    24.18      6.70     0.10   103.986    24.1809      1      a
 110.92    25.30      7.15     0.10   110.916    25.3009      1      a
 118.12    26.46      7.27     0.10   118.116    26.4610      1      a
 125.31    27.57      7.03     0.10   125.305    27.5710      1      a
 132.44    28.68      7.21     0.10   132.435    28.6811      1      a
 139.53    29.82      6.96     0.10   139.525    29.8211      1      a
 146.62    30.94      7.17     0.10   146.615    30.9411      1      a
 153.69    32.08      6.90     0.10   153.684    32.0812      1      a
 160.75    33.26      7.14     0.10   160.744    33.2612      1      a
 167.80    34.38      6.87     0.10   167.794    34.3813      1      a
 181.94    36.69      7.55     0.10   181.933    36.6913      1      a
 189.34    37.92      7.15     0.10   189.333    37.9214      1      a
 196.72    39.13      7.47     0.10   196.713    39.1314      1      a
 204.08    40.31      7.09     0.10   204.073    40.3115      1      a
 211.42    41.59      7.39     0.10   211.412    41.5915      1      a
 218.72    42.79      7.03     0.10   218.712    42.7916      1      a
 224.65    43.86      4.72     0.10   224.642    43.8616      1      a
 230.71    44.83      7.11     0.10   230.702    44.8316      1      a
 236.74    47.02      4.93     0.10   236.731    47.0217      1      a
 241.60    49.14      4.95     0.10   241.591    49.1418      1      a
 260.63    90.49      6.59     0.10   260.621    90.4933      1      a
 267.46    90.86      6.93     0.10   267.450    90.8633      1      a
 274.70    91.24      7.27     0.10   274.690    91.2433      1      a
 282.07    91.58      7.05     0.10   282.060    91.5834      1      a
 289.49    91.90      7.41     0.10   289.479    91.9034      1      a
 297.07    92.30      7.18     0.10   297.059    92.3034      1      a
 305.06    92.59      7.53     0.10   305.049    92.5934      1      a
 208.02    35.30      8.80     0.10   208.012    35.3013      2      a
 217.40    36.71      9.75     0.10   217.392    36.7113      2      a
 224.96    38.20      5.38     0.10   224.952    38.2014      2      a
 231.08    38.76      6.76     0.10   231.072    38.7614      2      a
 236.98    39.64      5.00     0.10   236.971    39.6415      2      a
 241.87    42.53      4.67     0.10   241.861    42.5316      2      a
 250.96    90.14      6.63     0.10   250.951    90.1433      2      a
 257.61    90.47      6.46     0.10   257.601    90.4733      2      a

Notes and References

• Key: T(orig .) - experimental temperatures (K) listed in Table III of Hornung and Giauque (1955), based upon 0 ^oC = 273.16 K; Cp(orig.) - experimental heat capacities (cal mol^-1 K^-1) listed in Table III of Hornung and Giauque (1955), based upon 0 ^oC = 273.16 K, and defining 1 calorie as equal to 4.1833 international joules; ΔT - temperature difference over which the heat capacity was measured; T(corr .) and Cp(corr.) - temperatures and heat capacities corrected to 0 ^oC = 273.15 K (T(orig .) is multiplied by 273.15/273.16, and Cp(orig.) is multiplied by 273.16/273.15); error - estimated percentage error in smoothed values of Cp, see note below; ref. - source of data.
• The defined calorie of Kunzler and Giauque is equal to 4.184 J.
• Source: a - E. W. Hornung and W. F. Giauque (1955) J. Amer. Chem. Soc. 77, 2983-2987.
• Solid H2SO4 · 3.999H2O melts at 244.89 K (on the same temperature scale as T(orig .)), and measured heat capacities above this temperature are for the liquid. Measurements from about 220 K to the melting point include heat effects due to eutectic fusion and pre-melting. The data are corrected for this in the tables of smoothed values of heat capacities presented by Giauque et al. (W. F. Giauque et al. (1960) J. Amer. Chem. Soc. 82, 62-70).

7.  Heat Capacities of Aqueous Sulphuric Acid

 T(orig.)   Cp(orig.)     T(corr.)   Cp(corr.)  nH2O    series   ref.
  213.73     115.84       213.732    115.8442   6.003     -       a                                  
  221.25     117.54       221.242    117.5443   6.003     -       a                                  
  229.34     119.29       229.332    119.2944   6.003     -       a                                  
  237.54     120.74       237.531    120.7444   6.003     -       a                                  
  245.93     122.22       245.921    122.2245   6.003     -       a                                  
  254.61     123.60       254.601    123.6045   6.003     -       a                                  
  263.65     124.75       263.640    124.7546   6.003     -       a                                  
  272.70     125.76       272.690    125.7646   6.003     -       a                                  
  281.74     126.33       281.730    126.3346   6.003     -       a                                  
  290.86     126.85       290.849    126.8546   6.003     -       a                                  
  299.76     127.04       299.749    127.0447   6.003     -       a 
  213.17     143.00       213.162    143.0052   8.001     -       a                                  
  220.82     146.47       220.812    146.4754   8.001     -       a                                  
  228.81     149.98       228.802    149.9855   8.001     -       a                                  
  236.71     153.11       236.701    153.1156   8.001     -       a                                  
  244.52     155.91       244.511    155.9157   8.001     -       a                                  
  252.60     158.29       252.591    158.2958   8.001     -       a                                  
  261.08     160.41       261.070    160.4159   8.001     -       a                                  
  269.90     161.92       269.890    161.9259   8.001     -       a                                  
  278.67     163.38       278.660    163.3860   8.001     -       a                                  
  287.19     163.89       287.179    163.8960   8.001     -       a                                  
  295.68     164.19       295.669    164.1960   8.001     -       a                                  
  230.18     126.89       230.172    126.8947   6.501     1       a                                  
  236.69     128.65       236.681    128.6547   6.501     1       a                                  
  244.03     130.40       244.021    130.4048   6.501     1       a                                  
  251.38     131.50       251.371    131.5048   6.501     1       a                                  
  258.75     133.13       258.741    133.1349   6.501     1       a                                  
  266.14     133.57       266.130    133.5749   6.501     1       a                                  
  273.25     134.62       273.240    134.6249   6.501     1       a                                  
  280.89     135.24       280.880    135.2450   6.501     1       a                                  
  289.06     135.78       289.049    135.7850   6.501     1       a                                  
  296.61     136.34       296.599    136.3450   6.501     1       a                                  
  295.26     136.09       295.249    136.0950   6.501     2       a                                  
  303.00     136.55       302.989    136.5550   6.501     2       a                                  
  310.81     136.83       310.799    136.8350   6.501     2       a                                  
  318.81     136.99       318.798    136.9950   6.501     2       a                                  

Notes and References

• Key: T(orig .) - experimental temperatures (K) listed in Table III of Hornung et al. (1956), based upon 0 ^oC = 273.16 K; Cp(orig.) - experimental heat capacities (cal mol^-1 K^-1) listed in Table III of Hornung et al.(1956), based upon 0 ^oC = 273.16 K; T(corr .) and Cp(corr.) - temperatures and heat capacities corrected to 0 ^oC = 273.15 K (T(orig .) is multiplied by 273.15/273.16, and Cp(orig.) is multiplied by 273.16/273.15); nH2O - number of moles of water per mole of H2SO4 in each solution; ref. - source of data.
• The defined calorie of Hornung et al. is equal to 4.184 J.
• Source: a - E. W. Hornung, T. E. Brackett and W. F. Giauque (1956) J. Amer. Chem. Soc. 78, 5747-5751.

8.  Heat Capacities of Aqueous H2SO4 at 25 ^oC and -20 ^oC

wt%(orig.)   wt%(corr.)    Cp      t     series     ref. 
  96.05        95.877    0.3499    25      1         a
  95.30        95.128    0.3549    25      1         a
  94.59        94.420    0.3594    25      1         a
  93.89        93.721    0.3647    25      1         a
  93.20        93.032    0.3703    25      1         a
  92.49        92.324    0.3764    25      1         a
  91.81        91.645    0.3823    25      1         a
  91.16        90.996    0.3881    25      1         a
  90.48        90.317    0.3946    25      1         a
  89.82        89.658    0.3996    25      1         a
  89.20        89.039    0.4068    25      1         a
  88.61        88.451    0.4133    25      1         a
  87.96        87.802    0.4184    25      1         a
  87.35        87.193    0.4237    25      1         a
  86.71        86.554    0.4285    25      1         a
  86.03        85.875    0.4346    25      1         a
  85.39        85.236    0.4384    25      1         a
  84.77        84.617    0.4420    25      1         a
  84.20        84.048    0.4442    25      1         a
  84.20        84.048    0.4430    25      1         a
  83.59        83.440    0.4464    25      1         a                                          
  82.99        82.841    0.4482    25      1         a                                          
  82.40        82.252    0.4491    25      1         a                                          
  81.74        81.593    0.4501    25      1         a                                          
  80.89        80.834    0.4507    25      1         a                                          
  80.19        80.046    0.4515    25      1         a                                          
  79.33        79.187    0.4531    25      1         a                                          
  79.33        79.187    0.4519    25      1         a                                          
  79.33        79.187    0.4533    25      1         a                                          
  78.28        78.119    0.4542    25      1         a                                          
  77.30        77.161    0.4558    25      1         a                                          
  76.19        76.053    0.4570    25      1         a                                          
  75.08        74.945    0.4602    25      1         a                                          
  73.84        73.707    0.4627    25      1         a                                          
  72.49        72.360    0.4674    25      1         a                                          
  71.05        70.922    0.4723    25      1         a                                          
  71.05        70.922    0.4733    25      1         a                                          
  71.05        70.922    0.4721    25      1         a                                          
  69.40        69.275    0.4787    25      1         a                                          
  102.66      102.476    0.3247    25      2         a                                          
  102.35      102.166    0.3255    25      2         a                                          
  102.05      101.866    0.3270    25      2         a                                          
  101.72      101.537    0.3278    25      2         a                                          
  101.37      101.188    0.3288    25      2         a                                          
  101.03      100.848    0.3299    25      2         a                                          
  100.71      100.528    0.3317    25      2         a                                          
  100.39      100.210    0.3327    25      2         a                                          
  99.97        99.930    0.3370    25      2         a                                          
  99.78        99.740    0.3358    25      2         a                                          
  99.91        99.870    0.3363    25      3         a                                          
  99.22        99.180    0.3353    25      3         a                                          
  98.65        98.610    0.3366    25      3         a                                          
  98.01        97.970    0.3406    25      3         a                                          
  97.38        97.341    0.3422    25      3         a                                          
  96.77        96.732    0.3447    25      3         a                                          
  96.13        96.092    0.3489    25      3         a                                          
  95.51        95.472    0.3526    25      3         a                                          
  13.457       13.457    0.8909    25      3a        a                                          
  13.457       13.457    0.8878    25      3a        a                                          
  13.457       13.457    0.8895    25      3a        a                                          
  13.457       13.457    0.8905    25      3a        a                                          
  10.775       10.775    0.9101    25      3a        a                                          
  10.775       10.775    0.9126    25      3a        a                                          
  29.075       29.075    0.7742    25      3b        a                                          
  22.545       22.545    0.8228    25      3b        a                                          
  17.350       17.350    0.8616    25      3b        a                                          
  13.192       13.192    0.8917    25      3b        a                                          
  10.127       10.127    0.9142    25      3b        a                                          
  66.12        66.12     0.4940    25      4         a                                          
  62.68        62.68     0.5117    25      4         a                                          
  58.69        58.69     0.5360    25      4         a                                          
  52.58        52.58     0.5777    25      4         a                                          
  46.499       46.499    0.6262    25      4         a                                          
  36.301       36.301    0.7149    25      4         a                                          
  27.401       27.401    0.7877    25      4         a                                          
  75.17        75.17     0.4400    25      6         a                                          
  71.96        71.96     0.4519   -20      6         a                                          
  69.66        69.66     0.4636   -20      6         a                                          
  65.86        65.86     0.4827   -20      6         a                                          
  62.51        62.51     0.5020   -20      6         a                                          
  58.14        58.14     0.5302   -20      6         a                                          
  54.17        54.17     0.5537   -20      6         a                                          
  49.040       49.04     0.5900   -20      6         a                                          
  43.156       43.156    0.6343   -20      6         a                                          
  37.333       37.333    0.6834   -20      6         a                                          
  30.662       30.662    0.7346   -20      6         a                                          

Notes and References

• Key: wt%(orig.) - the weight percentage of H2SO4 in the solution defined according to the equation given below; wt%(corr.) - values corrected as given in the footnotes of Giauque et al. (W. F. Giauque et al. (1960) J. Amer. Chem. Soc. 82, 62-70); Cp - experimental heat capacities (cal mol^-1 K^-1) listed in Table V of reference (a); t - the experimental temperature (^o C); ref. - source of data.
• Source: a - J. E. Kunzler and W. F. Giauque (1952) J. Amer. Chem. Soc. 74, 3472-3476.
• The defined calorie of Kunzler and Giauque is equal to 4.184 J.
• weight percentage of H2SO4 is equal to (98.082/80.066) × (wt.SO3 × 100)/(wt.SO3 + wt.H2O). Molar masses of 98.082 (H2SO4) and 18.016 (water) were used by Kunzler and Giauque.

9.  Apparent Molar Heat Capacities of Dilute Aqueous H2SO4

  mH2SO4      φCp       t     ref.                                 
  1.0127     41.45      10     a
  0.7973     32.17      10     a
  0.5635     20.24      10     a
  0.4724     14.66      10     a
  0.3780      9.69      10     a
  0.2848      2.07      10     a
  0.1781     -8.55      10     a
  0.1035    -21.98      10     a
  1.0127     69.13      25     a
  0.7973     64.97      25     a
  0.5635     60.74      25     a
  0.4724     59.32      25     a
  0.3780     58.18      25     a
  0.2848     57.71      25     a
  0.1781     58.13      25     a
  0.1035     58.61      25     a
  1.1027     72.75      40     a
  0.7973     70.33      40     a
  0.5635     68.05      40     a
  0.4724     68.19      40     a
  0.3780     68.82      40     a
  0.2848     70.75      40     a
  0.1781     75.48      40     a
  0.1035     83.57      40     a
  1.0127     65.19      55     a
  0.7973     63.37      55     a
  0.5635     61.76      55     a
  0.4724     61.50      55     a
  0.3780     62.32      55     a
  0.2848     64.61      55     a
  0.1781     70.83      55     a
  0.1035     83.72      55     a

Notes and References

• Key: mH2SO4 - the molality of H2SO4 (mol per kg of water) in the solution, listed in Table 1 of ref. (a); φCp - the apparent molar heat capacity of H2SO4 (J mol^-1 K^-1), t - the experimental temperature (^oC); ref. - source of data.
• Source: a - J. K. Hovey and L. G. Hepler (1990) J. Chem. Soc., Faraday Trans. 86, 2831-2839.

10.  Apparent Molar Heat Capacities of Dilute Aqueous H2SO4

  mH2SO4    φCp     t     ref.
  0.0520    47.6    25     a
  0.1521    51.9    25     a
  0.1973    55.3    25     a
  0.2432    52.9    25     a
  0.2960    55.5    25     a
  0.3538    53.0    25     a
  0.3990    56.0    25     a
  0.4568    55.5    25     a
  0.5628    56.3    25     a

Notes and References

• Key: mH2SO4 - the molality of H2SO4 (mol per kg of water) in the solution, listed in Table 3 of ref. (a); φCp - calculated apparent molar heat capacities of H2SO4 (J mol^-1 K^-1), t - the experimental temperature (^oC); ref. - source of data.
• Source: a - J. W. Larson, K. G. Zeeb, and L. G. Hepler (1982) Can. J. Chem. 60, 2141-2150.

11.  Apparent Molar Heat Capacities of Dilute Aqueous H2SO4

   mH2SO4     Cp*      Cp(adj.)    φCp     t    ref. 
   0.0444   0.999318   0.994985   34.8396   25    a
   0.0704   0.999678   0.992823   43.3919   25    a
   0.0713   0.999648   0.992706   41.0818   25    a
   0.1748   1.000319   0.983458   32.8119   25    a
   0.3722   1.003603   0.968256   52.3221   25    a
   0.5515   1.005945   0.954324   53.0838   25    a
   0.8054   1.010330   0.936362   59.1283   25    a
   0.9941   1.014465   0.924339   65.3064   25    a
   1.2423   1.019210   0.908511   68.2406   25    a
   1.4580   1.024236   0.896091   72.5667   25    a
   1.4580   1.024876   0.896652   74.4053   25    a
   1.8771   1.034887   0.873979   80.1073   25    a
   2.2300   1.043677   0.856370   83.9218   25    a

Notes and References

• Key: mH2SO4 - the molality of H2SO4 (mol per kg of water) in the solution; Cp* - experimental heat capacities (cal K^-1 gH2O^-1) multiplied by 1.00111 as recommended by Giauque et al. (J. Amer. Chem. Soc. 82, 62-70, 1960) in order to adjust to the defined calorie of Giauque et al. which is equal to 4.184 J; Cp(adj.) - heat capacities Cp* adjusted to a "per gram of total material" basis and expressed in cal K^-1 g^-1; φCp - calculated apparent molar heat capacities of H2SO4 (units J mol^-1 K^-1); t - the experimental temperature (^oC); ref. - source of data.
• Source: a - M. Randall and M. D. Taylor (1941) J. Phys. Chem. 45, 959-967.

12.  Heat Capacities of Aqueous H2SO4 at approx. 20 ^oC

     nH2O     Cp          t     t(init.)   t(final)   ref.
     0.0000   0.3352    20.20     18.7       21.7     a
     0.1428   0.3404    20.35     18.8       21.9     a
     0.2976   0.3554    20.20     18.7       21.7     a
     0.4856   0.3786    20.20     18.8       21.6     a
     0.6483   0.4016    20.20     18.8       21.6     a
     0.9246   0.4345    20.30     18.8       21.8     a
     1.0000   0.4408    20.30     18.8       21.8     a
     1.1555   0.4466    20.55     19.0       22.1     a                                             
     1.5439   0.4517    20.45     18.9       22.0     a                                             
     2.000    0.4628    20.20     18.7       21.7     a                                             
     3.000    0.5012    20.00     18.5       21.5     a                                             
     4.000    0.5420    20.20     18.7       21.7     a                                             
     5.000    0.5805    20.20     18.7       21.7     a                                             
     6.000    0.6152    20.15     18.7       21.6     a                                             
     7.000    0.6475    20.20     18.7       21.7     a                                             
     8.000    0.6776    20.30     18.8       21.8     a                                             
     9.000    0.7020    20.10     18.6       21.6     a                                             
    10.00     0.7231    20.25     18.8       21.7     a                                             
    11.00     0.7412    20.25     18.8       21.7     a                                             
    12.00     0.7584    19.90     18.4       21.4     a                                             
    12.50     0.7647    19.90     18.5       21.3     a                                             
    13.00     0.7717    20.30     18.8       21.8     a                                             
    14.00     0.7837    20.10     18.6       21.6     a                                             
    15.00     0.7948    20.25     18.7       21.8     a                                             
    16.00     0.8041    20.20     18.7       21.7     a                                             
    17.00     0.8122    20.20     18.7       21.7     a                                             
    18.00     0.8203    20.20     18.7       21.7     a                                             
    19.00     0.8277    20.10     18.6       21.6     a                                             
    20.00     0.8339    20.10     18.6       21.6     a                                             
    30.00     0.8768    20.10     18.6       21.6     a                                             
    50.00     0.9171    20.30     18.8       21.8     a                                             
   100.0      0.9551    20.10     18.6       21.6     a                                             
   150.0      0.9688    20.15     18.7       21.6     a                                             
   200.0      0.9763    20.20     18.7       21.7     a                                             
   400.0      0.9877    20.15     18.7       21.6     a                                             
   800.0      0.9937    20.20     18.7       21.7     a                                             
  1600        0.99675   20.15     18.7       21.6     a                                             

Notes and References

• Key: nH2O - the composition of the acid solutions in moles of H2O per mol of H2SO4; Cp - experimental heat capacities (cal mol^-1 K^-1) listed in Table I of ref. (a); t - the experimental temperature (^oC), equal to the mean of the initial and final temperatures of the solution in the calorimetric experiment; t(init.) - initial solution temperature; t(final) - final solution temperature; ref. - source of data.
• Source: a - E. Biron (1899) Russ. Fiz.-Khim. Obsch. 31, 171-203.
• Clegg, Rard, and Pitzer (Clegg et al. (1994) J. Chem. Soc., Fraday Trans. 90, 1875-1894) assumed in their analysis that the heat capacity of pure water, for the calorie used by Biron, is 1.0 cal g^-1 K^-1 at the experimental temperature.

13.  Heat Capacities of Aqueous Sulphuric Acid

  wt%(H2SO4)    Cp           t       ref.
    6.06       0.949       22.5       a
   12.22       0.900       22.5       a
   18.20       0.859       22.5       a
   24.20       0.812       22.5       a
   30.30       0.766       22.5       a
   36.10       0.715       22.5       a
   40.00         -         22.5       a
   42.00       0.664       22.5       a
   45.30         -         22.5       a
   48.20       0.611       22.5       a
   53.80       0.567       22.5       a
   60.10       0.525       22.5       a
   65.00         -         22.5       a
   66.10       0.491       22.5       a
   72.20       0.464       22.5       a
   78.10       0.449       22.5       a
   82.80         -         22.5       a
   84.48       0.441       22.5       a
   85.00         -         22.5       a
   85.50         -         22.5       a
   87.60       0.416       22.5       a
   88.90         -         22.5       a
   92.50       0.372       22.5       a
   96.00         -         22.5       a
  100.00       0.332       22.5       a
    6.06       0.949       40.0       a
   12.22       0.897       40.0       a
   18.20       0.856       40.0       a
   24.20       0.810       40.0       a
   30.30       0.763       40.0       a
   36.10       0.718       40.0       a
   40.00         -         40.0       a
   42.00       0.666       40.0       a
   45.30         -         40.0       a
   48.20       0.616       40.0       a
   53.80       0.573       40.0       a
   60.10       0.532       40.0       a
   65.00         -         40.0       a
   66.10       0.500       40.0       a
   72.20       0.475       40.0       a
   78.10       0.462       40.0       a
   82.80       0.452       40.0       a
   84.48       0.445       40.0       a
   85.00         -         40.0       a
   85.50         -         40.0       a
   87.60         -         40.0       a
   88.90         -         40.0       a
   92.50       0.380       40.0       a
   96.00         -         40.0       a
  100.00       0.343       40.0       a
    6.06       0.948       60.0       a
   12.22       0.901       60.0       a
   18.20       0.852       60.0       a
   24.20       0.814       60.0       a
   30.30       0.765       60.0       a
   36.10       0.715       60.0       a
   40.00       0.684       60.0       a
   42.00       0.669       60.0       a
   45.30       0.640       60.0       a
   48.20       0.626       60.0       a
   53.80       0.584       60.0       a
   60.10       0.542       60.0       a
   65.00       0.516       60.0       a
   66.10       0.510       60.0       a
   72.20       0.487       60.0       a
   78.10       0.468       60.0       a
   82.80       0.457       60.0       a
   84.48       0.448       60.0       a
   85.00       0.446       60.0       a
   85.50       0.444       60.0       a
   87.60       0.432       60.0       a
   88.90         -         60.0       a
   92.50       0.391       60.0       a
   96.00       0.364       60.0       a
  100.00       0.351       60.0       a
    6.06       0.947       80.0       a
   12.22       0.894       80.0       a
   18.20         -         80.0       a
   24.20       0.801       80.0       a
   30.30       0.757       80.0       a
   36.10         -         80.0       a
   40.00       0.685       80.0       a
   42.00       0.671       80.0       a
   45.30       0.642       80.0       a
   48.20       0.622       80.0       a
   53.80       0.583       80.0       a
   60.10       0.548       80.0       a
   65.00       0.524       80.0       a
   66.10         -         80.0       a
   72.20       0.499       80.0       a
   78.10         -         80.0       a
   82.80       0.464       80.0       a
   84.48       0.455       80.0       a
   85.00       0.452       80.0       a
   85.50       0.449       80.0       a
   87.60       0.438       80.0       a
   88.90       0.429       80.0       a
   92.50       0.399       80.0       a
   96.00       0.374       80.0       a
  100.00       0.359       80.0       a

Notes and References

• Key: wt% - the composition of the acid solutions in weight percent of H2SO4; Cp - experimental heat capacities (cal g^-1 K^-1); t - the experimental temperature (^oC); ref. - source of data.
• Source: a - Savarizky (also sometimes cited as Wrewsky), as tabulated by A. S. Socolik (1932) Z. Phys. Chem. 158A, 305-312.