To determine whether the given processes are exothermic or endothermic, let’s analyze each one:
- A. When solid KBr is dissolved in water, the solution gets colder: This process is endothermic. When KBr dissolves, it absorbs heat from the surrounding water, resulting in a decrease in temperature of the solution.
- B. Natural gas (CH4) is burned in a furnace: This process is exothermic. The combustion of natural gas releases a significant amount of heat energy, which is why it is used in heating systems.
- C. When concentrated sulfuric acid is added to water, the solution gets very hot: This process is exothermic. Mixing sulfuric acid with water releases a large amount of heat, which can be dangerous if not done carefully.
- D. When water evaporates: This process is endothermic. Water absorbs heat from its surroundings to change from liquid to gas, which decreases the temperature of the surrounding environment.
Understanding whether a reaction is exothermic or endothermic is crucial for various applications, including industrial processes and safety measures.