Closed System

Definition

A closed system is a physical system that does not allow matter to enter or leave, though energy can be exchanged with its surroundings. This concept is essential in understanding how energy transformations occur within a defined boundary, which is crucial for analyzing processes such as heat transfer and work done on or by the system. Closed systems simplify the analysis of mass and energy balances by isolating the system from external influences while allowing for energy interactions.

5 Must Know Facts For Your Next Test

1. In a closed system, the total mass remains constant because there is no mass transfer across the system boundaries.
2. Energy can be transferred in the form of heat or work in a closed system, which can change the internal energy of the system.
3. The First Law of Thermodynamics applies to closed systems, stating that the change in internal energy equals the heat added minus the work done by the system.
4. Closed systems are often used in engineering calculations because they simplify mass and energy balance equations.
5. Real-world examples of closed systems include sealed containers where chemical reactions occur without any matter escaping.

Review Questions

• How does a closed system differ from an open system in terms of mass and energy exchanges?
  • A closed system only allows energy exchanges with its surroundings while keeping mass constant within its boundaries, meaning no matter enters or leaves. In contrast, an open system permits both mass and energy transfers, complicating the analysis due to the continuous flow of material. This distinction is crucial when applying mass and energy balances, as it influences the equations used to model processes.
• Discuss how the First Law of Thermodynamics relates to closed systems and provides insights into energy conservation.
  • The First Law of Thermodynamics states that the change in internal energy of a closed system is equal to the heat added to the system minus the work done by it. This relationship highlights energy conservation within a closed system since all changes in internal energy result from energy interactions without mass transfer. Understanding this principle helps in analyzing energy transformations during various processes like heating or performing work.
• Evaluate the significance of using closed systems in engineering applications and how they influence design decisions.
  • Using closed systems simplifies calculations for engineers because it allows them to focus on energy changes without worrying about mass flow. This is particularly significant in designing thermal systems, reactors, and other equipment where precise control over energy transfer is essential. The ability to apply thermodynamic principles effectively to closed systems leads to optimized designs that enhance efficiency and performance, showcasing their importance in engineering practice.

Related terms

Open System: An open system allows both mass and energy to be exchanged with its surroundings, making it more complex in terms of analysis compared to closed systems.

Isolated System: An isolated system is one where neither matter nor energy can be exchanged with the surroundings, representing an extreme case of a closed system.

Thermodynamics: Thermodynamics is the branch of physics that deals with heat, work, temperature, and the laws governing these processes in various types of systems.