Question

How much energy is evolved during the formation of 98.7 g of fe, according to the reaction below? fe2o3(s) + 2 al(s) → al2o3(s) + 2 fe(s) δh°rxn = -852 kj?

Answer 1

 The energy that  evolved  during the formation  of 98.7g of Fe is   1505.5 Kj


calculation

find the number of moles of iron = mass/molar mass
molar mass of iron=  55.85 g/mol

moles = 98.7 g /55.85 g/mol = 1.767 moles

energy evolved  is therefore =  852  x 1.767 = 1505.5 Kj