The reaction in hand warmers is 4Fe(s)+3O2(g)==>2Fe2O3(s) ^H= -1652kj calculate the amount on energy released by a hand warmer that contains 1.25 g of Fe(s)

Answer 1

The ∆H of -1652 kJ is for the reaction as written. That is, it is the amount of heat released when 4 moles Fe react.

1.25 g Fe(s) x 1 mol Fe/55.85 g = 0.02238 moles Fe

0.02238 moles Fe x 1652 kJ/mol = 36.97 kJ = 37.0 kJ of energy released (3 sig. figs.)