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PHYSICS 2 JEROME DUA WABINGGA, LPT  Raise your hand if you Seat Properly. want to answer. Listen if somebody is talking. Respect each other.  What have you known about Thermodynamics?  Thermodynamics: Fundamentals and Applications...

PHYSICS 2 JEROME DUA WABINGGA, LPT  Raise your hand if you Seat Properly. want to answer. Listen if somebody is talking. Respect each other.  What have you known about Thermodynamics?  Thermodynamics: Fundamentals and Applications Learning objectives: a. Define the thermodynamics; b. Describe the fundamentals in thermodynamics; c. Understand the basic concepts of thermodynamics. INTRODUCTION The study of thermodynamics is concerned with ways energy is stored within a body and how energy transformations, which involve heat and work, may take place. Approaches to studying thermodynamics ◦ Macroscopic (Classical thermodynamics) ◦ study large number of particles (molecules) that make up the substance in question ◦ does not require knowledge of the behavior of individual molecules ◦ Microscopic (Statistical thermodynamics) ◦ concerned within behavior of individual particles (molecules) ◦ study average behavior of large groups of individual particles 6 7 8 The Zeroth Law of Thermodynamics states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This law establishes the concept of temperature and forms the foundation for temperature measurement. In simpler terms: ✓ If system A is in thermal equilibrium with system C, ✓ and system B is in thermal equilibrium with system C, ✓ then system A and system B are in thermal equilibrium with each other. 9 The zeroth law allows the definition of temperature scales. It implies that temperature is a transitive property, enabling the use of thermometers to measure the temperature of various systems consistently. 10 The First Law of Thermodynamics, also known as the law of energy conservation, states that energy cannot be created or destroyed in an isolated system. The total energy of a system and its surroundings remains constant. This can be expressed mathematically as: In essence, the first law of thermodynamics emphasizes that the energy added to a system as heat, minus the energy lost as work, results in a change in the system's internal energy. 11 The Second Law of Thermodynamics states that the total entropy of an isolated system can never decrease over time. Entropy, often interpreted as the measure of disorder or randomness in a system, tends to increase, leading to the eventual equilibrium state where entropy is maximized. This law can be stated in several ways: 1.Clausius Statement: Heat cannot spontaneously flow from a colder body to a hotter body. 2.Kelvin-Planck Statement: It is impossible to convert all the heat from a heat source into work without any loss of energy. 12 In practical terms, the second law implies that natural processes tend to move towards a state of maximum entropy, and it explains why some processes are irreversible and why perpetual motion machines of the second kind are impossible. 13 The Third Law of Thermodynamics, also known as Nernst's theorem, states that as the temperature of a system approaches absolute zero (0 Kelvin), the entropy of a perfect crystal approaches zero. In other words, the entropy of a system at absolute zero is a well-defined constant, typically taken to be zero for a perfect crystal. 14 Key implications of the third law include: 1.Absolute Zero: It is impossible to reach absolute zero in a finite number of steps. As a system approaches absolute zero, the entropy change for any process approaches zero. 2.Perfect Crystals: At absolute zero, a perfect crystal (where the arrangement of atoms is perfectly ordered) has only one possible microstate, resulting in zero entropy. The third law reinforces the idea that as temperature decreases, the entropy change in any process becomes smaller, and all processes slow down significantly, making absolute zero unattainable in practice. 15 Thermodynamic Systems Thermodynamic System ◦ quantity of matter or a region of space chosen for study Boundary ◦ real or imaginary layer that separates the system from its surroundings Surroundings ◦ physical space outside the system boundary Types of Systems ◦ Closed ◦ Open 1-2 Closed Systems (fixed masses) Energy, not mass, crosses closed-system boundaries (Fig. 1-13)  1-3 Closed System with Moving Boundry 1-4 Open Systems (Control Volumes) Mass and Energy Cross Control Volume Boundaries  Isolated System Isolated system boundary Closed system where no heat or work (energy) may cross the system boundary ◦ typically a collection of the a main work system system (or several systems) and its mass Surr 1 heat surroundings is considered an isolated system Surr 2 Surr 3 Total Energy of a System Sum of all forms of energy (i.e., thermal, mechanical, kinetic, potential, electrical, magnetic, chemical, and nuclear) that can exist in a system For systems we typically deal with in this course, sum of internal, kinetic, and potential energies E = U + KE + PE E = Total energy of system U = internal energy KE = kinetic energy = mV2/2 PE = potential energy = mgz  1-5 System’s Internal Energy System’s Internal Energy = Sum of Microscopic Energies Properties Any characteristic of a system in equilibrium is called a property. Types of properties ◦ Extensive properties - vary directly with the size of the system Examples: volume, mass, total energy ◦ Intensive properties - are independent of the size of the system Examples: temperature, pressure, color Extensive properties per unit mass are intensive properties. specific volume v = Volume/Mass = V/m density  = Mass/Volume = m/V State & Equilibrium State of a system ◦ system that is not undergoing any change ◦ all properties of system are known & are not changing ◦ if one property changes then the state of the system changes Thermodynamic equilibrium ◦ “equilibrium” - state of balance ◦ A system is in equilibrium if it maintains thermal (uniform temperature), mechanical (uniform pressure), phase (mass of two phases), and chemical equilibrium Processes & Paths Process ◦ when a system changes from one equilibrium state to another one ◦ some special processes: ◦ isobaric process - constant pressure process ◦ isothermal process - constant temperature process ◦ isochoric process - constant volume process ◦ isentropic process - constant entropy (Chap. 6) process Path ◦ series of states which a system passes through during a process 26 27