According to the following reaction, how much energy is required to decompose

Question

According to the following reaction, how much energy is required to decompose 4.8 kg of Fe ₃O ₄? The molar mass of Fe ₃O ₄ is 231.55 g/mol.

 Fe ₃O ₄(s) → 3 Fe(s) + 2 O ₂(g) ΔH° _rxn = +1118 kJ 

Answer 1

Fe₃O₄(s) → 3Fe(s) + 2O₂(g) ... ΔH° rxn = +1118 kJ 

According to this reaction, it takes 1118 kJ of energy (heat) to decompose 1 mole of Fe₃O₄(s)

We will first find the moles of Fe₃O₄ present:

4.8 kg x 1000 g/kg x 1 mol / 231.55 g = 20.73 moles Fe₃O₄

Now we find the heat energy needed to decompose this amount of Fe₃O₄:

20.73 mol Fe₃O₄ x 1118 kJ/mol = 23,176 kJ

Finally, rounding to correct # of sig. figs. we have 23,000 kJ