CALCIUM HYDROXIDE - (1305-62-0)

Introduction

Name: calcium hydroxide
* IUPAC
CAS Number: 1305-62-0
Chemical Formula: Ca(OH)2
Molar Mass: 74.09268 g
Mass Percent: Ca 54.091 %; O 43.187 %; H 2.7207 % 

Classification

• inorganic

Uses/Function

• "slaked lime...an inexpensive base for which industry finds many uses. When slaked lime is mixed with sand and exposed to the CO2 of the air, it hardens to form mortar." 1

• "Softening [in chemical water analysis]" 2

• "Hydrangea colors ultimately depend on the availability of aluminum ions (Al3+) within the soil...But in neutral to basic soil, the ions combine with hydroxide ions (OH-) to form immobile aluminum hydroxide, Al(OH)3. Consequently, for the bluing of hydrangea blooms, one needs both aluminum ions and acidic soil. The best soil aadditive for bluing is one that combines both, such as commercially available aluminum sulfate, Al2(SO4)3. Conversely, if one wishes to change blue blooming hydrangea to red-blooming, adding lime (calcium hydroxide, Ca(OH)2) results in basic soil and the desired color transition." 3

Solubility

Ksp:5.02·10-6 4

Bonding

Thermochemistry

ΔHf° (s): -235.70 kcal/mol 5 = -986.17 kJ/mol
S° (s): 19.93 cal/(mol•K) 6 = 83.39 J/(mol•K)
ΔGf° (s): -214.75 kcal/mol 7 = -898.51 kJ/mol

Reactions

For More Information

Sources

(1) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 931.
(2) - Hammer, Mark J. Water and Wastewater Technology, 2nd ed.; Prentice Hall: Englewood Cliffs, NJ, 1986; p 9.
(3) - Schreiber, Henry D. Curious Chemistry Guides Hydrangea Colors. American Scientist. 2014, 102, 444.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 8:119-8:122.
(5) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(6) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(7) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(8) - T < 3441.21637800303
(9) - T < 2637.94498381877
(10) - T > 1905.15260912373