28. t 3.61 points Ch. Ex. 137b- of Formation of Ca(OH)2 1 out of 3 attempts Lime
ID: 1035366 • Letter: 2
Question
28. t 3.61 points Ch. Ex. 137b- of Formation of Ca(OH)2 1 out of 3 attempts Lime is a term that includes calciam oxide (CaO, also called quicklime) and calcimm kydroside Assistance (Ca(OH)2 also called slaked lime). It is ased in the steel indastry to remove acidic imparities, in air-pollution costrol to remove acidic osides such as SQ, and in water treatuest. Slaked lise in produced by treating quicklime with water: AH--65.2 kJml Given the standard enthalpies of formation of CaO and H20 are -635.6 kJ/mol and -285s kJ/mol, respectively, calcalate the standard enthalpy of formation of Ca(OH) kJ/molExplanation / Answer
consider the given reaction
CaO + H2O ----> Ca(OH)2
by definiton
dHo rxn = (dHof Ca(OH)2 ) - ( dHof CaO + dHof H2O)
given
dHo rxn = -65.2 kJ/mol
dHof CaO = -635.6 kJ/mol
dHof H2O = -285.8 kJ/mol
plug in the values
-65.2 = dHof Ca(OH)2 - ( -635.6 - 285.8)
dHof Ca(OH)2 = -986.6 kJ/mol
so
the standard enthalpy of formation of Ca(OH)2 is -986.6 kJ/mol