Question

Consider the reaction:C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O(l); DH = -1.37 x 103 kJConsider the following propositions:I. The reaction is endothermic.II. The reaction is exothermic.III. The enthalpy term would be different if the water formed wasgaseous.Which of these propositions is (are) true?A. IB. IIC. IIID. I, IIE. II, III

Answer 1

Answer:

E. II, III

Explanation:

Let's consider the following reaction.

C₂H₅OH(l) + 3 O₂(g) ⇒ 2 CO₂(g) + 3 H₂O(l)

ΔH = -1.37 × 10³ kJ

Consider the following propositions:

I. The reaction is endothermic. FALSE. By convention, if the enthalpy of the reaction ΔH is negative, the reaction is exothermic.

II. The reaction is exothermic. TRUE.

III. The enthalpy term would be different if the water formed was gaseous. TRUE. The enthalpy of the reaction depends on the enthalpies of formation  (ΔHf) of reactants and products. ΔHf of H₂O(l) is different from ΔHf of H₂O(g).