what will the sign on ∆s be for the following reaction and why? 2 mg (s) o₂ (g) → 2 mgo (s) a) positive, because there is a solid as a product. b) positive, because there are more moles of reactant than product. c) positive, because it is a synthesis reaction. d) negative, because there are more moles of gas on the reactant side than the product side. e) negative, because there are more moles of reactant than product.