Identify each of the following processes as exothermic or endothermic. a. Freezi
ID: 726369 • Letter: I
Question
Identify each of the following processes as exothermic or endothermic.a. Freezing of water:
H2O(l) ? H2O(s)
b. Sublimation of ice:
H2O(s) ? H2O(g)
c. Combustion of ethanol (a fuel in many new gasoline formulations):
CH3CH2OH(l) + 3O2(g) ? 2CO2(g) + 3H2O(g)
d. Important hydrogen-powered automobile reaction:
2H2 + O2 ? 2H2O
e. Human metabolism of carbohydrates, i.e., "burning carbs:"
CH2O + O2 ? H2O + CO2 (simplified representation)
f. Reaction of the pollutant nitric oxide in the atmosphere:
2NO(g) + O2(g) ? 2NO2(g) ??Hrxn = -113 kJ
Explanation / Answer
(a) exothermic (b) endothermic (c) exothermic (d) exothermic (e) exothermic (f) exothermic