If 3.500 g of Ni are reacted with excess oxygen to form nickel oxide (NiO) under standard state conditions, what is the entropy change for the reaction?

Question

Quizplus · Accepted Answer

The balanced chemical equation for the reaction is:
Ni(s) + O2(g) -> NiO(s)
From standard entropy data, we have:
ΔS°(Ni,s) = 30.91 J/K
ΔS°(O2,g) = 205.0 J/K
ΔS°(NiO,s) = 37.31 J/K
ΔS°rxn = ΣS°(products) - ΣS°(reactants) = ΔS°(NiO,s) - [ΔS°(Ni,s) + ΔS°(O2,g)]
= 37.31 J/K - [30.91 J/K + 205.0 J/K] = -198.6 J/K ≈ -199 J/K ≈ -201 J/K (to 2 significant figures)
Therefore, the correct answer is (C) (F1F1F1S1F1F1F1014.7 J/K).

If 3500 G of Ni Are Reacted with Excess Oxygen to to Form