Classify the same processes as exothermic or endothermic.
 Evaporation of alcohol from skin: liquid C3H30 +5.2 kJ → vaporized C3H30
 Burning of propane in a gas grill: C3H8 +502 — 3C02 + 4H20 + 1652 kJ
 Oxidation of iron to form rust 4Fe +30, 2Fe2O3 +2221 kJ