Portable hot packs are available for skiers and other people engaged in other outdoor activities in a cold climate. The air-permeable paper packet contains a mixture of powdered iron, sodium chloride, and other components, all moistened by a little water. The exothermic reaction that produces the heat is a very common one, the rusting of iron: 4Fe(s) + 3O2(g) → 2Fe2O3(s) When the outside plastic envelope is removed, O2 molecules penetrate the paper, causing the reaction to begin. A typical packet contains 250. g of iron to warm your hands or feet for up to 4 hours. Calculate the amount of heat (in kJ) associated with this reaction.