Republic of the Philippines EASTERN VISAYAS STATE UNIVERSITY Tacloban City COLLEGE OF ENGINEERING EE DEPARTMENT ASSIGNMENT NO.1 ME-312 Basic Thermodynamics Name: Malasaga, Grezel M. Course/Year & Section: BSEE-3B Date: September 14, 2022 Instructor: Engr. Jay Gabriel F. Jimenez QUESTIONS: 1. Define a thermodynamic system. Differentiate between open system, closed system, and an isolated system. 2. How does a homogeneous system differ from a heterogeneous system? 3. What do you mean by a pure substance? 4. Explain the following terms: (i) State, (ii) Process, and (iii) Cycle. 5. Briefly explain zeroth law of thermodynamics. 6. What is a quasi-static process and reversible work? ANSWERS: 1. Thermodynamic system refers to the quantity of matter or certain volume in space chosen for study. Open system is a system in which there is a flow of matter through the boundary. It usually encloses the device that involves mass flow, such as: compressor, turbine, or nozzle. While in closed system, it is a system in which there is no transfer of matter across the boundary. It consists of a fixed amount of mass, and no mass can cross its boundary. That is, no mass can enter or leave a closed system. And lastly, the isolated system is a system in which neither mass nor energy cross the boundaries and is not influenced by the surroundings. 2. A homogeneous thermodynamic system is defined as the one whose chemical composition and physical properties are the same in all parts of the system, or change continuously from one point to another. A homogeneous system can be exemplified by imagining a column of atmospheric air, which is a mixture of a number of gases, mainly nitrogen and oxygen. In a system of this kind, acted upon by the force of gravity, both the composition of the system and its physical properties will continuously change from one point to another. While the heterogeneous system, it is denned as one consisting of two or more homogeneous bodies. The homogeneous bodies of a heterogeneous system are referred to as phases. Each phase is separated from other phases by interfaces, or boundaries, and in passing over such a boundary the chemical composition of the substance or its physical properties abruptly change. This phase boundary must not be regarded as a mathematical surface but as a thin layer separating the phases, a layer where the properties of one phase pass, or turn, rapidly into the properties of the other phase. 3. Pure substance is a substance that has a fixed chemical composition throughout, such as water, air, and nitrogen. A pure substance does not have to be of a single element or compound. 4. State of a system represents condition of the system and the condition of the system is identified by properties. The system is said to be in a state if all the properties of system are fixed. If the state of a system changes, then it is undergoing a process. The succession of states through which the system passes defines the path of the process. If, at the end of the process, the properties have returned to their original values, the system has undergone a cyclic process or a cycle. 5. The Zeroth Law of thermodynamics states that, if two bodies are each in thermal equilibrium with some third body, then they are also in equilibrium with each other. 6. Quasi-static process is the process in which every instantaneous states is equilibrium and reversible process is the quasi-static process in which the entropy does not increase, but the quasi-static is not necessarily a reversible, that depends on the entropy—increasing or not.
