Question

For an endothermic process, \(q\) will have a (positive/negative) sign.

Short answer

For an endothermic process, the heat transfer (\(q\)) will have a positive sign.

Step-by-step solution

Understanding an endothermic process

An endothermic process is a physical or chemical process that absorbs heat from its surroundings. In other words, heat flows from the surroundings into the system.

Determining the sign of \(q\) for an endothermic process

In thermodynamics, if heat is absorbed by the system (as in an endothermic process), \(q\) is considered positive. Conversely, if heat is released from the system to the surroundings (exothermic process), \(q\) is considered negative.

Conclusion

For an endothermic process, the heat transfer (\(q\)) will have a positive sign.

Key concepts

Thermodynamics and Heat in Endothermic Processes

Thermodynamics is the branch of physics that deals with the relationship between heat and other forms of energy. In this context, understanding the nature of endothermic processes is crucial.

An endothermic process is one that requires the absorption of heat from its surroundings, leading to an increase in the internal energy of the system. In thermodynamics, symbols hold significance, such as the letter 'q' which represents the quantity of heat transferred. During an endothermic reaction or physical change, 'q' is assigned a positive value because the system is gaining heat energy. This aligns with the law of conservation of energy, which stipulates that energy cannot be created or destroyed, only transferred.

Heat Transfer in Physical and Chemical Contexts

Heat transfer is a fundamental concept in both physical and chemical processes. It can occur in three primary ways: conduction, convection, and radiation. In the case of an endothermic reaction, the important point is that heat flows into the system from the surrounding environment.

When studying chemical reactions or phases changes in physics, recognizing the direction of heat flow helps scientists and students understand whether the process is endothermic or exothermic. An endothermic process, which encompasses a positive heat transfer (positive 'q'), signifies that the surrounding temperature may drop as heat is absorbed by the system. This is a distinctive characteristic of endothermic reactions, as they often feel cold to the touch.

Physically Observing Endothermic and Exothermic Processes

Physics and chemistry often overlap when observing physical and chemical processes. Endothermic processes can be identified not just by measuring temperature changes but also through careful observation of energy transformations and matter interactions.

For example, during the melting of ice (an endothermic phase change), heat is absorbed from the surroundings to break the bonds between the water molecules, transitioning them from solid to liquid. This is easily observable through the melting process. Not every physical process is as apparent, but by leveraging the principles of thermodynamics and understanding the heat transfer involved, students can predict and explain the energy changes during such processes.