Question

Classify the following processes as exothermic or endothermic: (a) freezing of water; (b) boiling of water; (c) digestion of food; (d) a person running; (e) a person growing; (f) wood being chopped; (g) heating with a furnace.

Short answer

(a) Exothermic, (b) Endothermic, (c) Exothermic, (d) Exothermic, (e) Endothermic, (f) Neither, (g) Exothermic

Step-by-step solution

- Understand Exothermic and Endothermic Processes

Exothermic processes release energy into the surroundings, usually in the form of heat. Endothermic processes absorb energy from the surroundings.

- Analyze Freezing of Water

Freezing of water releases heat. Therefore, it is an exothermic process.

- Analyze Boiling of Water

Boiling of water absorbs heat. Therefore, it is an endothermic process.

- Analyze Digestion of Food

Digestion of food releases energy. Therefore, it is an exothermic process.

- Analyze a Person Running

Running expends energy from the body, which is released largely as heat. Therefore, it is an exothermic process.

- Analyze a Person Growing

Growth processes generally require energy to build new cells and tissues. Therefore, it is an endothermic process.

- Analyze Wood Being Chopped

Chopping wood is primarily a mechanical process without significant heat exchange. It is neither significantly exothermic nor endothermic.

- Analyze Heating with a Furnace

Heating with a furnace releases energy in the form of heat. Therefore, it is an exothermic process.

Key concepts

heat exchange

Heat exchange is a vital concept in understanding exothermic and endothermic processes. It refers to the transfer of heat energy between a system and its surroundings. For instance, when water freezes, heat is released to the environment. This release of heat is called an exothermic process. On the other hand, when water boils, it absorbs heat from the surroundings, which is an endothermic process. Heat exchange helps to balance energy in natural processes and is essential in many chemical reactions.

energy absorption

Energy absorption occurs when a system takes in energy from its surroundings. In endothermic reactions, energy is absorbed to break chemical bonds or change the state of matter. For example, boiling water requires the absorption of heat to transition from liquid to gas. Similarly, when a person is growing, energy is absorbed to build new cells and tissues. This absorbed energy is often in the form of heat or light and is crucial for various biological and chemical processes.

energy release

Energy release is the process of energy exiting a system and transferring to the surroundings. Exothermic reactions are known for releasing energy, often as heat or light. For instance, when food is digested in the body, it releases energy that powers bodily functions. Running also exemplifies an exothermic process, where energy is mainly released as heat from the body. These releases of energy are vital for maintaining equilibrium and enabling various physical activities and reactions.

thermodynamics

Thermodynamics is the branch of physics that deals with heat, work, and energy. It helps us understand how energy is converted and transferred. The laws of thermodynamics are essential in explaining exothermic and endothermic processes. For instance, the First Law of Thermodynamics states that energy cannot be created or destroyed, only transferred or exchanged. This principle helps us understand how energy is conserved in processes such as the boiling of water (endothermic) or the digestion of food (exothermic). By studying thermodynamics, we gain insights into the efficiency and behavior of different reactions and systems.

chemical reactions

Chemical reactions are processes where substances undergo transformations to form new substances. They can be classified as exothermic or endothermic based on their energy exchange. In exothermic chemical reactions, energy is released, making the surroundings warmer. For example, burning wood in a furnace is an exothermic reaction because it releases heat. Conversely, in endothermic reactions, energy is absorbed, causing the surroundings to be cooler. An example is the growth of a person, where energy is taken in to build new cells. Understanding the energy dynamics in chemical reactions is crucial for fields like chemistry, biology, and environmental science.