Please help me with chemistry and heat

Question

The highly exothermic thermite reaction, in which aluminum reduces iron(III) oxide to elemental iron, has been used by railroad repair crews to weld rails together.

2 Al(s) + Fe₂O₃(s)  2 Fe(s) + Al₂O₃(s) ΔH = -850 kJ

What mass of iron is formed when 725 kJ of heat are released?

A. 47 g

B. 65 g     

C. 95 g

D.130 g

E. 112 g

Answer 1

From the equation and the information provided, we know that 2 moles of Fe is formed when 850 kJ of heat are released.

Since we have only 725 kJ of heat releases, we can determine the moles of Fe equivalent to this.

725 kJ x 2 mols Fe / 850 kJ = 1.71 mols Fe formed from 725 kJ

atomic mass Fe = 55.8 g/ mol

mass of Fe formed = 1.71 mols Fe x 55.8 g/mol = 95.2 g (Answer C)