AHP for the formation of rust (Fe2O3) is - 826 kJ/mol. How much energy is

involved in the formation of 5.00 grams of rust?

A 25.9 kJ

B 25.9 J

C 66.0 kJ

D 66.0)

A - 25.9 kJ

Explanation:

ΔH of formation is defined as the amount of energy that is involved in the formation of 1 mole of substance.

ΔH of rust is - 826kJ/mol, that means when 1 mole of rust is formed, there are released - 826kJ.

Moles of 5.00g of Fe₂O₃ (Molar mass: 159.69g/mol) are:

5.00g ₓ (1 mole / 159.69g) = 0.0313 moles of Fe₂O₃.

If 1 mole release - 826kJ, 0.0313 moles release:

0.0313 moles ₓ (-826kJ / 1 mole) = - 25.9kJ

Thus, heat involved is:

A - 25.9 kJ