5.1 Concept and Statements of the Second Law. 8 THERMAL ENERGY RESERVOIRS • A hypothetical body with a relatively large thermal energy capacity … First Law: Heat and Work are both forms of Energy. First Law of Thermodynamics. • This is always observed to occur spontaneously. Second Law of Thermodynamics 16-20 3.1 Second Law of Thermodynamics 16 3.2 Entropy 16 3.3 Entropy of a Perfect Gas 18 3.4 Temperature Dependence of Entropy 19 3.5 Reversible & Irreversible Process 20 4. A reaction or change of state is said to be spontaneous if it is thermodynamically allowed.! The total energy of the universe is constant, but the entropy is increasing. The fi rst law of thermodynamics, that energy is conserved, just ells us what can happen; it is the second law that makes things go. W can never be equal to Q. •The second law of thermodynamics can determine the preferred direction for the processes. Here is a lecture to understand 2nd law of thermodynamics in a conceptual way. The Second Law of Thermodynamics . We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. Physical processes in nature can proceed toward equilibrium spontaneously: Water flows down a waterfall. The total energy of the universe is constant, but the entropy is increasing. This is a statement of the second law of thermodynamics. Note:This is an idealized situation where the system is already at equilibrium, hence the process will proceed infinitestimally slow. •In quasi-equilibrium process, the system can keep close to equilibrium state and nearly reversible. Presentation Title: Second Law Of Thermodynamics 186592. There are several ways in which the second law of thermodynamics can be stated. 1. Presentation Title: Second Law Of Thermodynamics (yac Ch.5) Identifies The Direction Of A. The second law of thermodynamics is a consequence of the theory of probability: the world changes the way it does because it seeks a state of probability. The second law of thermodynamics has several consequences regarding the Carnot cycle. Flow of mass does carry an amount of entropy. 6.1 Introduction. Presentation Summary : Heat engine QH TH Wnet A heat engine has to reject some energy into a lower temperature sink in order to complete the cycle. Second Law of Thermodynamics In any spontaneous process there is always an increase in the entropy of the universe. Uploaded on: Jan 17, 2017. The second law of thermodynamics can be described by the following two theories. Ch 1 - Introduction: Basic Concepts of Thermodynamics. You can change your ad preferences anytime. Zeroth law of thermodynamics:-Zeroth law of thermodynamics states that when two systems are each in thermal equilibrium with the third system, they are also in thermal equilibrium with each other. The second law of thermodynamics is considered to be the most fundamental law of science. See our User Agreement and Privacy Policy. Universities and Professors Knewton’s Content Team The Second and Third Laws of Thermodynamics: Instruction ACHIEVEMENT WITHIN REACH | 7 Explain the Second Law of Thermodynamics There are three possibilities for such a process: 1. It explains not only the working of engines, refrigerators and other equipments used in our daily life, but also highly advanced theories like big bang, expansion of universe, heat death etc. • Not a good predictor. Mechanical Department In symbols: dU = dQ + dW. The second law of thermodynamics says that the entropy of any isolated system always increases. Topic:~ Second law of thermodynamic Energy or Enthalpy: ∆U or ∆H! If "S total >0, then the process is naturally occurring and it is "irreversible". second law of thermodynamics 169728 Powerpoint Presentation . 1. The anal-ysis of thermal systems is achieved through the application of the governing conservation equations, namely Conservation of Mass, Conservation of Energy (1st law of thermodynam-ics), the 2nd law of thermodynamics and the property relations. When we sum up all the changes of entropy of interacting subsystems, the total change must be nonnegative. Entropy & the Second Law ! The second law (the law of entropy increase) is valid for a whole (isolated) system. Like the first law, it is a generalization from an enormous amount of observation. The first law is concerned with the quantity of energy and the The second law of thermodynamics says this is impossible. Everything outside of the boundary is considered the surrounding… Topic 10.3Second Law of Thermodynamicsand Entropy. in any process, Energy can be changed from one form to another (including heat and work), but it is never created or distroyed: Conservation of Energy . The final entropy must be greater than the initial entropy for an irreversible process: Sf > Si (irreversible process) An example of an irreversible process is the problem discussed in the second paragraph. The Second Law of Thermodynamics The second law of thermodynamics states that processes occur in a certain direction, not in just any direction. – A 100% efficient Carnot engine would convert all heat absorbed from a warm reser-voir into work, in direct contraction to the second law. •In reversible process, the thermodynamic process can be reversed and are thus equilibrium processes. (1.6-1) d S = δ Q rev T. Note that although δ Q rev is a path function δ Q rev / T is a state function. The Second Law of Thermodynamics states that "in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the See our User Agreement and Privacy Policy. carnot's cycle, Thermodynamic Chapter 4 Second Law Of Thermodynamics, No public clipboards found for this slide. Isolated systems spontaneously evolve towards thermodynamic equilibrium, the state with maximum entropy. Basics of Energy Conversion cycles; Second Law of Thermodynamics. First Law of Thermodynamics; Pure Substances & Steam Tables and Ideal & Real Gases. Some energy must always be transferred as heat to the system’s surrounding. State of system & state function : State of system is described in terms of T, P, V etc. (Basic concepts & Statements) The Second Law of Thermodynamics . Listed below are three that are often encountered. 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