An endothermic process is a reaction or process that absorbs heat from its surroundings. Let's break down the options given:
1. Burning wood in a campfire: This is an exothermic process because it releases heat and energy into the surroundings. Therefore, it is not an example of an endothermic process.
2. A liquid evaporating into a gas: This is an endothermic process. When a liquid evaporates into a gas, it absorbs heat from its surroundings to overcome the intermolecular forces holding the liquid molecules together. This absorption of heat makes it an endothermic process.
3. A piece of iron rusting: Rusting of iron is an exothermic process because it releases heat as the iron reacts with oxygen in the presence of water to form iron oxide (rust). So, this is not an example of an endothermic process.
4. Strong hydrochloric acid dissolving in water: The dissolution of strong hydrochloric acid in water is an exothermic process. It releases heat as the acid molecules interact with water molecules. Therefore, this is not an example of an endothermic process.
Therefore, the example of an endothermic process among the options given is: a liquid evaporating into a gas.
