How much heat is evolved or absorbed in this problem?

Question

Question Details
Limestone, CaCo3, when subjected to a temperature of 900 degrees Celsius in a kiln, decomposes to calcium oxide and carbon dioxide. How much heat is evolved or absorbed when one gram of limestone decomposes?

The standard enthalpies of formation at 25 degrees Celsius(kj/mol) of these compounds at 1 atm, Aqueous ions at 1 M is:

CaCO3 -1206.9
CaO -635.1
CO2 -393.5

Answer 1

See your post above. n = 1 in this case.