Consider the reaction:
C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O(l); DH = -1.37 x 103 kJ

Consider 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. I
B. II
C. III
D. I, II
E. II, III

Respuesta :

Answer:

The correct answer is E.

Explanation:

Given the reaction:

C₂H₅OH (l) + 3 O₂(g) ⇒ 2 CO₂ (g) + 3 H₂O (l) ; ΔH = -1.37×10³ kJ

We can see that ΔH is negative. This means that the product formation energy is less than the reagent formation energy. In other words, the reaction releases heat and is therefore an exothermic reaction.

In addition, the enthalpy of formation of liquid water has different value than the enthalpy of formation of gaseous water. Therefore, the enthalpy variation would have a different value if the water formed was in a gaseous state.

Finally, the propositions II and III are true.