Classify each process according to direction of heat flow.
Evaporation of alcohol from skin: liquid C3H2O + 5.2 kJ → vaporized C3H30
Burning of propane in a gas grill: C3H8 + 502 — 3CO2 + 4H2O + 1652 kJ
Oxidation of iron to form rust: 4Fe + 302 → 2Fe2O3 + 2221 kJ