To determine whether each process is endothermic or exothermic, we need to consider the heat transfer associated with each process.
-
A fire (the system is the fire):
- A fire releases heat as it burns fuel (such as wood or gasoline), resulting in an increase in temperature of the surroundings. Since the fire is releasing heat, this process is exothermic.
-
A car engine (the system is the engine):
- A car engine burns fuel to produce energy, which generates heat. The combustion process releases energy as heat to the surrounding environment. Therefore, the car engine process is also exothermic.
-
A melting ice sculpture (the ice is the system):
- When ice melts, it absorbs heat from its surroundings in order to change from solid to liquid. In this case, heat is taken in by the ice for the phase change to occur. Thus, the melting process is endothermic.
To summarize:
- Fire: Exothermic
- Car engine: Exothermic
- Melting ice sculpture: Endothermic