7.71 Classify each of the following as exothermic or endothermic:
a. CHÂ(g) + 2O₂(g) —^> CO₂(g) + 2H₂O(g) + 802 kJ
b. Ca(OH)₂(s) + 65.3 kJ →→→ CaO(s) + H₂O(l)
c. 2Al(s) + Fe₂O3(s) — Al₂O3(s) + 2Fe(s) + 850 kJ

Respuesta :

A. Heat is released, so the reaction is exothermic.

B. Heat is absorbed, so the reaction is endothermic.

C. Heat is released, so the reaction is exothermic.