posted by Jason on .
How much energy will be released when 11.11g of calcium chloride dissolves in 100 mL of water.
deltaHf of Ca 2+ (aq)=-543Kj/mol,
deltaHf of Cl 1-(aq) = -167Kj/mol
CaCl2(s) ==> Ca 2+(aq) + 2Cl 1-(aq)
See if this sounds reasonable to you.
moles CaCl2 = 11.11/110.98 = 0.1 mole
Ca = 0.1 mol
Cl = 0.2 mol
Ca = 543 kJ/mol x 0.1 mol = -54.3 kJ.
Cl = 167 kJ/mol x 0.2 mol = -33.4 kJ.
Total released = sum of the two.