Question

consider the following two reactions: (i) 2c₂h₄o(ℓ) + 2h₂o → 2c₂h₆o + o₂(g) δh = 715.6 kj (ii) c₂h₅oh(ℓ) + 3o₂(g) → 2co₂(g) + 3h₂o(ℓ) δh = -1360 kj which of the following rows correctly matches the two reactions? row i ii a. exothermic exothermic b. endothermic endothermic c. endothermic exothermic d. exothermic endothermic a b c d none of the above

Explanation:

Step1: Recall the definition of endothermic and exothermic reactions

An endothermic reaction has $\Delta H> 0$ (absorbs heat), and an exothermic reaction has $\Delta H < 0$ (releases heat).

Step2: Analyze reaction (i)

For reaction (i), $\Delta H=715.6\space kJ>0$. So, reaction (i) is endothermic.

Step3: Analyze reaction (ii)

For reaction (ii), $\Delta H = - 1360\space kJ<0$. So, reaction (ii) is exothermic.

Answer:

C. Endothermic, Exothermic