Question

Question #47b4c

Answer 1

The problem contains its solution: the reaction is exothermic with: q = -799 kJ, provided thermal energy goes out from the reaction system.

Explanation:

This reaction coincides with the formation of two moles of iron(III) trichloride.

You can check from this table from wikipedia that the enthalpy decreases of 399.4 kJ when one mole of iron and 1.5 moles of dichlorine are reacted to give one mole of iron trichloride.

The formation of two moles of `FeCl_3` will thus devolve `399.4*2 = 798.8 kJ ≃799 kJ` of heat, as stated in the problem statement.