Second law of thermodynamics

All About Physics Quiz The law states that if two bodies are each in The first law of thermodynamics Within an isolated system, the total energy of the system is constant, even if energy has been converted from one form to another. (This is another way of stating the U is equal to the difference between the heat Q added to the system from its surroundings and the work W done by the system on its surroundings; that is, Δ U = Q − W. The second law of thermodynamics

\( \newcommand\) • • • • • • • • • • • • Irreversibility The second law of thermodynamics deals with the direction taken by spontaneous processes. Many processes occur spontaneously in one direction only—that is, they areirreversible, under a given set of conditions. Although irreversibility is seen in day-to-day life—a broken glass does not resume its original state, for instance—complete irreversibility is a statistical statement that cannot be seen during the lifetime of the universe. More precisely, an irreversible process is one that depends on path. If the process can go in only one direction, then the reverse path differs fundamentally and the process cannot be reversible. For example, heat involves the transfer of energy from higher to lower temperature. A cold object in contact with a hot one never gets colder, transferring heat to the hot object and making it hotter. Furthermore, mechanical energy, such as kinetic energy, can be completely converted to thermal energy by friction, but the reverse is impossible. A hot stationary object never spontaneously cools off and starts moving. Yet another example is the expansion of a puff of gas introduced into one corner of a vacuum chamber. The gas expands to fill the chamber, but it never regroups in the corner. The random motion of the gas molecules could take them all back to the corner, but this is never observed to happen. One-Way Processed in Nature: Examples of one-way processes in nature. (a) Heat transfer occurs ...

https://eng.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Feng.libretexts.org%2FBookshelves%2FMechanical_Engineering%2FIntroduction_to_Engineering_Thermodynamics_(Yan)%2F06%253A_Entropy_and_the_Second_Law_of_Thermodynamics%2F6.04%253A_The_second_law_of_thermodynamics-_Kelvin-Planck_and_Clausius_statements \( \newcommand\) No headers The first law of thermodynamics focuses on energy conservation. It does not describe any restrictions or possibilities for a process to take place. A process satisfying the first law of thermodynamics may or may not be achievable in reality. In fact, whether a process is possible is governed by both the first and the second laws of thermodynamics. There are two classical statements of the second law of thermodynamics; one imposes the limits on the operation of heat engines, and the other on the operation of refrigerators and heat pumps. Kelvin-Planck Statement: it is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce only a net amount of work. , thus resulting in a thermal efficiency . Figure 6.3.1 Schematic illustrating Kelvin-Planck statement Clausius statement: it is impossible to construct a device that operates in a cycle and produces no effect other than the transfer of heat from a lower-temperature body to a higher-temperature body. , , and thus a . Figure 6.3.2 Schematic illustrating the Clausius statement Although the Kelvin–Planck and Clausius statements refer to different c...

Next: Up: Previous: 5. 1 Concept and Statements of the Second Law (Why do we need a second law?) There are several ways in which the second law of thermodynamics can be stated. Listed below are three that are often encountered. As described in class (and as derived in almost every thermodynamics textbook), although the three may not appear to have much connection with each other, they are equivalent. • No process is possible whose sole result is the absorption of heat from a reservoir and the conversion of this heat into work. [Kelvin-Planck statement of the second law] For an isolated system the total energy ( ) is constant. The entropy can only increase or, in the limit of a reversible process, remain constant. The limit, or , represents the best that can be done. In thermodynamics, propulsion, and power generation systems we often compare performance to this limit to measure how close to ideal a given process is. All of these statements are equivalent, but Entropy is not a familiar concept and it may be helpful to provide some additional rationale for its appearance. If we look at the first law, Two out of the three terms in this equation are expressed in terms of state variables. It seems plausible that we ought to be able to express the third term using state variables as well, but what are the appropriate variables? If so, the term should perhaps be viewed as analogous to where the parentheses denote an intensive state variable and the square brackets denote an exten...

The second law of thermodynamics states that as energy is transferred or transformed, more and more of it is wasted. It's one of the four quantity of energy in the universe stays the same. The Second Law of Thermodynamics is about the nature of energy. The Second Law also states that there is a natural tendency of any isolated system to degenerate into a more disordered state, according to Saibal Mitra, a professor of physics at Missouri State University, finds the Second Law to be the most interesting of the four Mitra explained that all processes result in an increase in entropy. Even when order is increased in a specific location, for example by the self-assembly of molecules to form a living organism, when you take the entire system including the environment into account, there is always a net increase in entropy. In another example, crystals can form from a salt solution as the water is evaporated. Crystals are more orderly than salt molecules in solution; however, vaporized water is much more disorderly than liquid water. The process taken as a whole results in a net increase in disorder. This approach also led to the conclusion that while collisions between individual molecules are completely reversible, i.e., they work the same when played forward or backward, that's not the case for a large quantity of gas. With large quantities of gas, the speeds of individual molecules tend over time to form a normal or Gaussian distribution, sometimes depicted as a "bell curve,...

The thermodynamic time asymmetry is one of the most salient and consequential features of the physical universe. Heat flows from hot to cold, never the reverse. The smell of coffee spreads throughout its available volume, never the reverse. Car engines convert fuel energy into work and thermal energy, never the reverse. And so on. The science of thermodynamics is able to capture these generalizations as consequences of its claim that systems spontaneously evolve to future equilibrium states but do not spontaneously evolve away from equilibrium states. This generalization covers an amazing amount of macroscopic physics and is rightly celebrated as one of the great laws of physics. Despite its familiarity, however, the thermodynamic arrow of time raises many deep questions relevant to both philosophy and the foundations of physics. This entry concentrates on two of them. In contemporary parlance, they are each questions about grounding. (1) What grounds the thermodynamic asymmetry in time? In a world possibly governed at bottom by time-symmetric laws, how do the time-asymmetric laws of thermodynamics arise? (2) Does the thermodynamic time asymmetry ground any other temporal asymmetries? Does it account, for instance, for the fact that we know more about the past than the future? The discussion thus divides between thermodynamics being an explanandum or explanans. What grounds the thermodynamic asymmetry, and given the asymmetry, what does it ground? 1. Thermodynamic Time Asy...

3 Biological Macromolecules • Introduction • 3.1 Synthesis of Biological Macromolecules • 3.2 Carbohydrates • 3.3 Lipids • 3.4 Proteins • 3.5 Nucleic Acids • Key Terms • Chapter Summary • Review Questions • Critical Thinking Questions • Test Prep for AP®Courses • Science Practice Challenge Questions • 4 Cell Structure • Introduction • 4.1 Studying Cells • 4.2 Prokaryotic Cells • 4.3 Eukaryotic Cells • 4.4 The Endomembrane System and Proteins • 4.5 Cytoskeleton • 4.6 Connections between Cells and Cellular Activities • Key Terms • Chapter Summary • Review Questions • Critical Thinking Questions • Test Prep for AP®Courses • Science Practice Challenge Questions • 5 Structure and Function of Plasma Membranes • Introduction • 5.1 Components and Structure • 5.2 Passive Transport • 5.3 Active Transport • 5.4 Bulk Transport • Key Terms • Chapter Summary • Review Questions • Critical Thinking Questions • Test Prep for AP®Courses • Science Practice Challenge Questions • 6 Metabolism • Introduction • 6.1 Energy and Metabolism • 6.2 Potential, Kinetic, Free, and Activation Energy • 6.3 The Laws of Thermodynamics • 6.4 ATP: Adenosine Triphosphate • 6.5 Enzymes • Key Terms • Chapter Summary • Review Questions • Critical Thinking Questions • Test Prep for AP®Courses • Science Practice Challenge Questions • 7 Cellular Respiration • Introduction • 7.1 Energy in Living Systems • 7.2 Glycolysis • 7.3 Oxidation of Pyruvate and the Citric Acid Cycle • 7.4 Oxidative Phosphorylation • 7.5 Metabol...

12 Thermodynamics • Introduction • 12.1 Zeroth Law of Thermodynamics: Thermal Equilibrium • 12.2 First law of Thermodynamics: Thermal Energy and Work • 12.3 Second Law of Thermodynamics: Entropy • 12.4 Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators • Key Terms • Section Summary • Key Equations • 22 The Atom • Introduction • 22.1 The Structure of the Atom • 22.2 Nuclear Forces and Radioactivity • 22.3 Half Life and Radiometric Dating • 22.4 Nuclear Fission and Fusion • 22.5 Medical Applications of Radioactivity: Diagnostic Imaging and Radiation • Key Terms • Section Summary • Key Equations • Teacher Support The learning objectives in this section will help your students master the following standards: • (6) Science concepts. The student knows that changes occur within a physical system and applies the laws of conservation of energy and momentum. The student is expected to: • (G) analyze and explain everyday examples that illustrate the laws of thermodynamics, including the law of conservation of energy and the law of entropy. Section Key Terms Teacher Support [BL] [OL] [AL] Return again to the discussion of efficiency that was begun at the start of the module. Review the ideal gas law, laws of thermodynamics, and entropy. [OL] Ask students whether they can explain the limits on efficiency in terms of what they have now learned. Heat Engines, Heat Pumps, and Refrigerators In this section, we’ll explore how heat engines, heat pumps, and refrigerat...

• Afrikaans • العربية • Asturianu • Azərbaycanca • বাংলা • Беларуская • Български • Bosanski • Català • Čeština • Dansk • Deutsch • Eesti • Ελληνικά • English • Español • Esperanto • Euskara • فارسی • Français • Galego • 한국어 • Հայերեն • हिन्दी • Hrvatski • Bahasa Indonesia • Italiano • עברית • ქართული • Қазақша • Kreyòl ayisyen • Latina • Latviešu • Magyar • Bahasa Melayu • Nederlands • 日本語 • Norsk bokmål • Occitan • Oʻzbekcha / ўзбекча • ਪੰਜਾਬੀ • پنجابی • Polski • Português • Română • Русский • සිංහල • Slovenčina • Slovenščina • Српски / srpski • Srpskohrvatski / српскохрватски • Suomi • Svenska • தமிழ் • ไทย • Türkçe • Українська • اردو • Tiếng Việt • 文言 • 吴语 • 粵語 • 中文 The may not be easy for everybody to understand. You can help Wikipedia by reading ( April 2012) The second law of Differences in Entropy is a measure of spread of matter and energy to everywhere they have access. The most common wording for the second law of thermodynamics is essentially due to Rudolf Clausius: “ It is impossible to construct a device that produces no other effect than transfer of heat from lower temperature body to higher temperature body ” In other words, everything tries to maintain the same temperature over time. There are many statements of the second law which use different terms, but all mean the same thing. Another statement by Clausius is: An equivalent statement by Lord A transformation whose only final result is to convert heat, extracted from a source at constant temperature, ...