Decomposition Reaction of limestone

Question

The decomposition of limestone, CaCO3 into lime, CaO, and CO2 requires the addition of 178.1 kJ of heat per mole of CaCO3. 

a. Write a balanced equation. (I balanced this to CaCO3 --> CaO + CO2)

b. How much heat is needed to decompose 18.0g of CaCO3 

Answer 1

a.) Your balanced equation looks correct.

b.) The heat for 1 mole CaCO3 (100. g) = 178.1 kJ. Thus, 178.1 kJ/100.0 g x 18.0 g = 32.1 kJ (3 sig. figs.)