Appendix E: Water Properties

Water Density (kg/m3) at Different Temperatures (°C)
Temperature[1] Density
0 999.8395
4 999.9720 (density maximum)
10 999.7026
15 999.1026
20 998.2071
22 997.7735
25 997.0479
30 995.6502
40 992.2
60 983.2
80 971.8
100 958.4


A line graph is titled “Density of Water as a Function of Temperature.” The x-axis is titled “Temperature, degrees Celsius,” and the y-axis is titled “Density, Kilograms per cubic meter.” A line connects plot points at the coordinates 0 and 999.8395, 4 and 999.9720, 10 and 999.7026, 15 and 999.1026, 20 and 998.2071, 22 and 997.7735, 25 and 997.0479, 30 and 995.6502, 40 and 992.2, 60 and 983.2, 80 and 971.8, and 100 and 958.4.

Water Vapor Pressure at Different Temperatures (°C)
Temperature Vapor Pressure (torr) Vapor Pressure (Pa)
0 4.6 613.2812
4 6.1 813.2642
10 9.2 1226.562
15 12.8 1706.522
20 17.5 2333.135
22 19.8 2639.776
25 23.8 3173.064
30 31.8 4239.64
35 42.2 5626.188
40 55.3 7372.707
45 71.9 9585.852
50 92.5 12332.29
55 118.0 15732
60 149.4 19918.31
65 187.5 24997.88
70 233.7 31157.35
75 289.1 38543.39
80 355.1 47342.64
85 433.6 57808.42
90 525.8 70100.71
95 633.9 84512.82
100 760.0 101324.7


A line graph is titled “Vapor Pressure as a Function of Temperature.” The x-axis is titled “Temperature, degrees Celsius,” and the y-axis is titled “Vapor pressure, torr.” A line connects plot points at the coordinates 0 and 4.6, 4 and 6.1, 10 and 9.2, 15 and 12.8, 20 and 17.5, 22 and 19.8, 25 and 23.8, 30 and 31.8, 35 and 42.2, 40 and 55.3, 45 and 71.9, 50 and 92.5, 55 and 118.0, 60 and 149.4, 65 and 187.5, 70 and 233.7, 75 and 289.1, 80 and 355.1, 85 and 433.6, 90 and 525.8, 95 and 633.9, and 100 and 760.0.

Water Kw and pKw at Different Temperatures (°C)
Temperature Kw 10–14 pKw[2]
0 0.112 14.95
5 0.182 14.74
10 0.288 14.54
15 0.465 14.33
20 0.671 14.17
25 0.991 14.00
30 1.432 13.84
35 2.042 13.69
40 2.851 13.55
45 3.917 13.41
50 5.297 13.28
55 7.080 13.15
60 9.311 13.03
75 19.95 12.70
100 56.23 12.25


A line graph is titled “Water pK subscript W as a Function of Temperature.” The x-axis is titled “Temperature, degrees Celsius,” and the y-axis is titled “pK subscript W.” A line connects plot points at the coordinates 0 and 14.95, 5 and 14.74, 10 and 14.54, 15 and 14.33, 20 and 14.17, 25 and 14, 30 and 13.84, 35 and 13.69, 40 and 13.55, 45 and 13.41, 50 and 13.28, 55 and 13.15, 60 and 13.03, 75 and 12.7, and 100 and 12.25.

Specific Heat Capacity for Water
C°(H2O(l)) = 4184 J∙K−1∙kg−1 = 4.184 J∙g-1∙°C-1
C°(H2O(s)) = 1864 J∙K−1∙kg−1
C°(H2O(g)) = 2093 J∙K−1∙kg−1
Standard Water Melting and Boiling Temperatures and Enthalpies of the Transitions
Temperature (K) ΔH (kJ/mol)
melting 273.15 6.088
boiling 373.15 40.656 (44.016 at 298 K)
Water Cryoscopic (Freezing Point Depression) and Ebullioscopic (Boiling Point Elevation) Constants
Kf = 1.86°C∙kg∙mol−1 (cryoscopic constant)
Kb = 0.51°C∙kg∙mol−1 (ebullioscopic constant)
A line graph is titled “Water Full-Range Spectral Absorption Curve.” The x-axis is titled “Wavelength” and the y-axis is titled “Absorption ( 1 per meter ).” Evenly spaced tick marks on the x-axis denote 10 nanometers, 100 nanometers, 1 micrometer, 10 micrometers, 100 micrometers, 1 millimeter, and 10 millimeters. Evenly spaced tick marks on the y-axis denote 10 superscript negative two, 10 superscript negative one, 10 superscript zero, 10 superscript one, 10 superscript two, 10 superscript three, 10 superscript four, 10 superscript five, 10 superscript six, 10 superscript seven, and 10 superscript eight. Above the graph, horizontal lines indicate the range of wavelengths for U V, V I S, near I R , mid I R , far I R , and E H F. The graph contains one line that begins at 10 nanometers and a little more than 10 superscript six. Moving from left to right, this line ascends gradually until it reaches a point near 100 nanometers and 10 superscript eight. From this point, the line steeply descends to a point a little more than halfway between 100 nanometers and 1 micrometer, and slightly more than 10 superscript two. This point indicates the end of the range labeled “U V” and the beginning of the range labeled “V I S.” The range labeled “V I S” is shaded with a color spectrum including the full range of Roy G Biv colors. Here, the line briefly descends in the same path as before, and then steeply ascends to a point near 1 micrometer and 10 superscript zero. This point indicates the end of the range labeled “V I S” and the beginning of the range labeled “near I R.” The line continues its steep ascent, with short, abrupt descents in between, until it reaches a point a little more than halfway between 1 micrometer and 10 micrometers, and a little more than 10 superscript six. This point indicates the end of the range labeled “near I R” and the beginning of the range labeled “mid I R.” Here, the line moves steeply and sporadically up and down until it reaches a point a little more than halfway between 10 micrometers and 100 micrometers, and slightly more than 10 superscript five. This point indicates the end of the range labeled “Mid I R” and the beginning of the range labeled “Far I R.” The line descends very gradually to a point slightly more than 1 millimeter and slightly more than 10 superscript four. This point indicates the end of the range labeled “Far I R” and the beginning of the range labeled “E H F.” The line continues its gradual descent to 10 millimeters and slightly more than 10 superscript three. This point indicates the end of the range labeled “E H F.”
Figure 1. Water full-range spectral absorption curve. This curve shows the full-range spectral absorption for water. The y-axis signifies the absorption in 1/cm. If we divide 1 by this value, we will obtain the length of the path (in cm) after which the intensity of a light beam passing through water decays by a factor of the base of the natural logarithm e (e = 2.718281828).
  1. Data for t < 0 °C are for supercooled water ↵
  2. pKw = –log10(Kw) ↵

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