Consider the following reaction.

Question

2Fe2O3 --> 4Fe+3O2 Hrxn=+824.2

The Formation of 21.0 of Fe results in
1)the release of 77.5 kJ of heat.
2)the absorption of 3.10 × 102 kJ of heat.
3)the release of 4330 kJ of heat.
4)the absorption of 77.5 kJ of heat.
5)the release of 3.10 × 102 kJ of heat.
6)the absorption of 4330 kJ of heat.

Answer 1

Decomposition of ionic solids are usually endothermic. So throw out 1, 3, & 5.
Convert 21g Fe to moles and use the equation ratios.