CALCIUM SULFATE - (7778-18-9)

Introduction

Name: calcium sulfate
* IUPAC
CAS Number: 7778-18-9
Chemical Formula: CaSO4
Molar Mass: 136.1406 g
Mass Percent: Ca 29.438 %; S 23.552 %; O 47.008 % 

Classification

• inorganic

Uses/Function

• "Insol[uble] anhydrite is used in cement formulations and as a paper filler. Soluble anhydride, because of its strong tendency to absorb moisture, is useful as a drying agent for solids, organic liquids and gases; the dessicant used in laboratory and industry is known under the name drierite. This material can be regenerated repeatedly and reused without noticeable decrease in its dessicating efficiency." 1

Physical Properties

Melting Point:*
1460°C 2 = 1733.15 K = 2660°F

Density (g/cm3):
2.96 at room temperature/pressure 2
* - 1 atm pressure

Solubility

Ksp:4.93·10-5 3

Bonding

Thermochemistry

ΔHf° (s anhydrite insoluble): -342.76 kcal/mol 4 = -1,434.11 kJ/mol
ΔHf° (s alpha soluble): -340.64 kcal/mol 4 = -1,425.24 kJ/mol
ΔHf° (s beta soluble): -339.58 kcal/mol 4 = -1,420.80 kJ/mol
ΔHf° (s): -342.85 kcal/mol = -1434.5 kJ/mol 5
S° (s anhydrite insoluble): 25.5 cal/(mol•K) 6 = 106.69 J/(mol•K)
S° (s alpha soluble): 25.9 cal/(mol•K) 6 = 108.37 J/(mol•K)
S° (s beta soluble): 25.9 cal/(mol•K) 6 = 108.37 J/(mol•K)
S° (s): 25.45 cal/(mol•K) = 106.5 J/(mol•K) 7
ΔGf° (s anhydrite insoluble): -315.93 kcal/mol 8 = -1,321.85 kJ/mol
ΔGf° (s alpha soluble): -313.93 kcal/mol 8 = -1,313.48 kJ/mol
ΔGf° (s beta soluble): -312.87 kcal/mol 8 = -1,309.05 kJ/mol
ΔGf° (s): -315.97 kcal/mol = -1322.0 kJ/mol 9

Reactions

For More Information

Sources

(1) - The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 13th ed.; Budavari, S.; O'Neil, M.J.; Smith, A.; Heckelman, P. E.; Kinneary, J. F., Eds.; Merck & Co.: Whitehouse Station, NJ, 2001; entry 1711.
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4-50.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 8:119-8:122.
(4) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-10.
(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) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-10.
(8) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 5-10.
(10) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 217.
(11) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 186.
(12) - Zumdahl, Steven and Zumdahl, Susan A. Chemistry 9th ed.; Brooks/Cole: Belmont, CA, 2014; p 133.
(13) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 139.
(14) - Kotz, John C., Treichel, Paul, and Weaver, Gabriela. Chemistry & Chemical Reactivity 6th ed.; Thomson Brooks/Cole: Belmont, CA, 2006; p 166.