Homework #8.55 Hess's Law

[Mary Becerra 2D]

I think there is a typo/error in #8.55. The solutions manual says to that the second reaction given (2Al + O2 ----> Al2O3) doesn't change its enthalpy value even though the book differs from the manual. Basically, the book says the second reaction is 2Al + O2 ----> Al2O3 while the solutions manual says it's
2Al + 3/2O2 ---> Al2O3. Can anyone else confirm?

[Yashaswi Dis 1K]

I am not entirely sure but whichever one has the correct balanced equation (I think it's the one in solutions manual?). It makes sense for 3/2 to be a coefficient for O₂ to get 3 moles of oxygen in the product. Hope that helps a little!

[Kailey Brodeur 1J]

I don't know if this is helpful, but the first equation you stated is the balanced chemical equation while the second one is the chemical equation utilized to find enthalpy of formation as the reactants are in amounts designed to produce exactly one mole of product.