For table hot packs are available for skiers and other people engaged in other o
ID: 527631 • Letter: F
Question
For table 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) + 3O_2(g) rightarrow 2Fe_2O_3(s) When the outside plastic envelope is removed, O_2 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. (Enter your answer in scientific notation.)Explanation / Answer
for the reaction, 4Fe+3O2------->2Fe2O3, deltaH= -1625 Kj
4 mole of Fe generates 1625 Kj
1 mole = mass/molar mass, mass= molar mass= 56 gm
56 gm*4= 224 gm of Fe generates 1625 Kj of heat
250 gm of iron generates 250*1625/224 Kj =1814 Kj