DOCSLIB.ORG

Heat of Formation Enthalpy of Formation Enthalpy Summary

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Enthalpy of formation Heat of Formation 2Al(s) + Fe2O3(s) Al2O3(s) + 2Fe(s) •Using enthalpies of Standard Enthalpy formation, calculate the of Formation Hf (kJ/mol) standard change in NH3(g) -46 enthalpy for the NO2 (g) 34 H2O(l) -286 thermite reaction: Al2O3(s) -1676 •This reaction occurs Fe2O3(s) -826 when a mixture of CO2 -394 CH OH -239 powdered aluminum and 3 (l) C8H18(l) -269 iron(III) oxide is ignited with a magnesium fuse. Enthalpy Methanol (CH3OH) is often Standard Enthalpy Summary used as a fuel in high- of Formation Hf (kJ/mol) performance engines in race NH3(g) -46 •When a reaction is reversed, the cars. Using the data in Table, NO2 (g) 34 H O -286 magnitude of H remains the same, compare the standard enthalpy 2 (l) Al2O3(s) -1676 but the sign changes. of combustion per gram of Fe2O3(s) -826 •When the balanced equation for a methanol with that per gram of CO2 -394 CH OH -239 reaction is multiplied by an integer, gasoline. Gasoline is actually a 3 (l) C8H18(l) -269 the value of H for that reaction mixture of compounds, but must be multiplied by the same assume for this problem that integer. gasoline is pure liquid octane (C8H18). Summary II •The change in enthalpy for a given reaction can be calculated from the enthalpies of Laws of Thermodynamics formation of the reactants and products: • o o o Hrxn = SmHf (products) - SnHf (reactants) • Elements in their standard states are not o include in the Hrxn calculations. That is, o Hf for an element in its standard state is 0. 1 Intro Entropy and heat Most natural events involve a decrease in total energy and an increase in disorder. • Entropy is a measure of randomness or disorder of a system. • The energy that was “lost” was converted to heat. • Entropy gets the symbol S • An increase in energy/motion decreases the • Heat energy is the kinetic energy of an overall order (organization) of the system. object. • Energy is never created nor destroyed it • The more motion in an object the more simply changes form. random it becomes. Thermodynamics Heat • Thermo – heat; dynamic- change or motion. • ~is the total thermal energy of an object. • Thermodynamics- conversion of heat energy • Like all energy, heat is measured in joules (J) (into other forms or objects). • The terms hot, warm, cool and cold are st • 1 Law of Thermodynamics- the amount of always relative. energy in the universe is constant. Law of conservation of energy. • Heat is only noticed when there is a transfer • 2nd Law of Thermodynamics- Spontaneous from one object to another. processes, ones that happen on their own, • Heat always flows from hot to cold. involve an increase in entropy. Entropy in the • This due to the 2nd law of thermodynamics. universe is always increasing. Kinetic Energy Temperature • Temperature is a measure of the intensity • All atoms/molecules in any object are of the heat energy present. moving. • This is measured by the average kinetic • The faster they are moving the more kinetic energy of all atoms/molecules present. energy an object has. • In other words, it’s the average amount of • The heat energy or thermal energy is the heat energy that will transfer. total (sum of) kinetic energy of all particles • Temperature is measured in Fahrenheit, in an object. Celsius or Kelvin. 2 Converting between temperature Units of Temperature units • Here are some common temperatures in the • Kelvin = 273 + Celsius different scales • (9/5 Celsius) + 32 = Fahrenheit COMMON TEMPERATURES F C K • Convert 65° F to C and K freezing point of water 32 0 273 • 18° C, 291 K room temperature (comfortable) 68 20 293 • Convert 301 K to C and F human body temperature 98.6 37 310 Boiling point of water 212 100 373 • 28° C, 82° F Two objects • When two objects of different temperatures are Penny and water next to each other heat will transfer from the • Here is a hot penny about to higher temperature to the lower temperature be dropped in a large cup of object. water. • By the 2nd law of thermodynamics • The penny will have a higher • This is not necessarily the object with more temperature, intensity of heat energy. energy, but the water will have to have more thermal • Consider a hot penny dropped into a large cup energy due to the amount of of room temperature water. water present. The Zeroth Law of Penny and water Thermodynamics • When dropped in, the penny sizzles, and the heat flows • If two different systems or objects are at from the penny into the water. thermal equilibrium with the same object, • This is obvious, since you can then they must be at thermal equilibrium with each other. now touch the penny. • Even though the water had • Another way to state this is they must all be at the same temperature and therefore no more total energy than the transfer of heat will take place. penny. • This increases entropy. 3 Matter without heat energy Zeroth Law of thermodynamics • Solids have the lowest amount of kinetic • So back to the penny in the cup of water. energy, however their particles still vibrate. • If you cool it until molecules no longer • They are now at thermal equilibrium. vibrate... • If a spoon is introduced to the cup of water o o it will also reach a thermal equilibrium with • it is theorized this occurs at -273.15 C or - 459 the water. F or 0 K • By this law, if the spoon and penny are • This is called absolute zero. It is when all removed, they are at thermal equilibrium, or motion stops. the same temperature. • Scientists have made it to 0.000 000 02 K Third Law of Thermodynamics Problems with forcing extremes • Whenever you are heating something, heat is • As the temperature of a body approaches escaping somewhere. absolute zero, all processes cease and the • Why can’t you melt steel on your stove? entropy approaches a minimum value. • Natural gas flames are in the range of 1800-2000o C • This minimum value is almost zero, but not quite. • Steel melts around 1400oC, depending on the alloy. • The law continues that… • As it gets hotter more heat escapes to the surrounding area. • It is impossible for any procedure, no matter how idealized, to reduce any system to • You eventually reach a point where the amount of absolute zero in a finite number of steps. heat escaping the surrounding area equals the amount going into the substance. • Laws explain what, not why. • So it isn’t getting heated anymore. Reverse the problem Cont. • Whenever you are cooling something, (removing heat, there is NO cold energy) • Now of course you can correct this problem heat is always entering from somewhere. by getting a hotter flame, or by better • This is why there is such difficulty getting insulating the area around the steel. to absolute zero. • However, you would run into this same • How do you stop any heat from being able problem again at a higher temperature. to enter a substance? • No one knows. • Further corrections would be needed. • Which leads us right back to the Third Law of Thermodynamics. “It can’t be done” as a summary of all attempts so far. 4.
Recommended publications
  • On the Definition of the Measurement Unit for Extreme Quantity Values: Some Considerations on the Case of Temperature and the Kelvin Scale

    On the Definition of the Measurement Unit for Extreme Quantity Values: Some Considerations on the Case of Temperature and the Kelvin Scale

    ON THE DEFINITION OF THE MEASUREMENT UNIT FOR EXTREME QUANTITY VALUES: SOME CONSIDERATIONS ON THE CASE OF TEMPERATURE AND THE KELVIN SCALE Franco Pavese 1 1 Torino, Italy E-mail (corresponding author): [email protected] Abstract Many quantities are attributed a range of values that can apparently extend to infinity (on one side or both sides). In this respect, the definitions of their measurement units do not place any constraint to the maximum (or minimum) value for their validity. In general, that happens because those extreme values are far from being reached on the earth, or presently in experiments. However, since the same units are used also in fields of physics, chemistry or technology where they could occur—namely in the description of the universe in one sense, and in pico-nanoscale or particle physics in another sense—the issue of extreme values (not in statistical meaning here) is not irrelevant. The question placed and discussed in this paper is whether the present kelvin scale, based on Lord Kelvin’s second definition (our currently accepted concept of temperature), applies over a full range between bounds (0, ∞) or not, and about the concept of temperature in itself in the extremes regions. The aim, however, is not to provide an answer, but to suggest there are difficulties with the application of current concepts at extremes of temperature. Keywords: kelvin scale; Lord Kelvin proposals; extreme temperatures; temperature definition; unit definition 1 Introduction Many quantities have a range of values that can apparently extend to infinity (on one side or both sides). In this respect, the definition of their measurement units does not place any constraint to the maximum (or minimum) value for its validity.
  • 31 Jan 2021 Laws of Thermodynamics . L01–1 Review of Thermodynamics. 1

    31 Jan 2021 Laws of Thermodynamics . L01–1 Review of Thermodynamics. 1

    31 jan 2021 laws of thermodynamics . L01{1 Review of Thermodynamics. 1: The Basic Laws What is Thermodynamics? • Idea: The study of states of physical systems that can be characterized by macroscopic variables, usu- ally equilibrium states (mechanical, thermal or chemical), and possible transformations between them. It started as a phenomenological subject motivated by practical applications, but it gradually developed into a coherent framework that we will view here as the macroscopic counterpart to the statistical mechanics of the microscopic constituents, and provides the observational context in which to verify many of its predictions. • Plan: We will mostly be interested in internal states, so the allowed processes will include heat exchanges and the main variables will always include the internal energy and temperature. We will recall the main facts (definitions, laws and relationships) of thermodynamics and discuss physical properties that characterize different substances, rather than practical applications such as properties of specific engines. The connection with statistical mechanics, based on a microscopic model of each system, will be established later. States and State Variables for a Thermodynamical System • Energy: The internal energy E is the central quantity in the theory, and is seen as a function of some complete set of variables characterizing each state. Notice that often energy is the only relevant macroscopic conservation law, while momentum, angular momentum or other quantities may not need to be considered. • Extensive variables: For each system one can choose a set of extensive variables (S; X~ ) whose values specify ~ the equilibrium states of the system; S is the entropy and the X are quantities that may include V , fNig, ~ ~ q, M, ~p, L, ..
  • The Third Law of Thermodynamics Or an Absolute Definition for Entropy. Part

    The Third Law of Thermodynamics Or an Absolute Definition for Entropy. Part

    The third law of thermodynamics or an absolute definition for Entropy. Part 1 : the origin and applications in thermodynamics. Accepted for the revue: “La Météorologie ” / Revision 2 - December 2, 2019. by Pascal Marquet. Météo-France, CNRM/GMAP, Toulouse. Abstract This article describes the third law of thermodynamics. This law is often poorly known and is often decried, or even considered optional and irrelevant to describe weather and climate phenomena. This, however, is inaccurate and contrary to scientific facts. A rather exhaustive historical study is proposed here in order to better understand, in another article to come, why the third principle can be interesting for the atmosphere sciences. 1 Introduction Before being able to study in a second part the properties of entropy in the atmosphere, it is necessary to recall in this first part why its calculation poses certain problems in thermodynamics, problems whose solution passes through the invention and the application of the third law of thermodynamics which introduces a kind of absolute in the calculation of entropy. And the idea that certain absolutes may exist had preceded the establishment of the third law. 2 The notion of absolute temperature Thermodynamics teaches us that the notion of temperature corresponds to the measurement of the energy of the microscopic agitations of atoms or molecules in the solids, liquids or gases which constitute the environment which surrounds us, and therefore in particular in the atmosphere. Carnot (1824) was able to establish the existence of universal things, supposing that the perpetual motion of thermal machines was impossible. He first highlighted the existence of a maximum efficiency that depends only on the temperatures of the bodies between which these machines operate.
  • UBO & MPD Glossary

    UBO & MPD Glossary

    UBO & MPD Glossary December 2011 Aniline Point – The aromatics content of a hydrocarbon A. mixture. Abnormal Pressure - Reservoir pore fluid pressure that Annulus Friction Pressure (AFP) – Difference is not similar to normal saltwater gradient pressure. The between bottomhole pressure and choke pressure due to term is usually associated with higher than normal friction; a function of flow rate, hole geometry, surface pressure, increased complexity for the well designer and roughness, fluid properties. an increased risk of well control problems. Abnormal – American Petroleum Institute. pressure gradients exceed a 10-ppg equivalent fluid API density (0.52 psi per foot). Gradients below normal are API Gravity - arbitrary measurement of density adopted in called subnormal. 1921 by the American Petroleum Institute and the Bureau Absolute Pressure - pressure measured with respect to of Standards. zero pressure; the sum of atmospheric pressure and gauge Apparent Power - combination of real and reactive pressure. power. Absolute Temperature - temperature measured with Apparent Viscosity - Slope of the shear stress versus respect to absolute zero, in degrees Rankine or degrees velocity gradient for a fluid. For Newtonian fluids, the Kelvin. apparent viscosity equals the absolute viscosity. Absolute Viscosity - dynamic relationship between a Aromatics – Ring group chemical structure. Most force and the fluid motion. common are benzene, toluene, and xylene. Absolute Zero Temperature - temperature that B. prevents molecular motion. Back Pressure Valve - A flow control valve to provide - rate of change in velocity. Acceleration backflow control when running or pulling a string. Active data - continually updated data, based on latest Backup – Redundant equipment available to complete an operational data. operation in the event the primary equipment fails.
  • Nonequilibrium Thermodynamics and Scale Invariance

    Nonequilibrium Thermodynamics and Scale Invariance

    Article Nonequilibrium Thermodynamics and Scale Invariance Leonid M. Martyushev 1,2,* and Vladimir Celezneff 3 1 Technical Physics Department, Ural Federal University, 19 Mira St., Ekaterinburg 620002, Russia 2 Institute of Industrial Ecology, Russian Academy of Sciences, 20 S. Kovalevskaya St., Ekaterinburg 620219, Russia 3 The Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel; [email protected] * Correspondence: [email protected]; Tel.: +7-92-222-77-425 Academic Editors: Milivoje M. Kostic, Miguel Rubi and Kevin H. Knuth Received: 30 January 2017; Accepted: 14 March 2017; Published: 16 March 2017 Abstract: A variant of continuous nonequilibrium thermodynamic theory based on the postulate of the scale invariance of the local relation between generalized fluxes and forces is proposed here. This single postulate replaces the assumptions on local equilibrium and on the known relation between thermodynamic fluxes and forces, which are widely used in classical nonequilibrium thermodynamics. It is shown here that such a modification not only makes it possible to deductively obtain the main results of classical linear nonequilibrium thermodynamics, but also provides evidence for a number of statements for a nonlinear case (the maximum entropy production principle, the macroscopic reversibility principle, and generalized reciprocity relations) that are under discussion in the literature. Keywords: dissipation function; nonequilibrium thermodynamics; generalized fluxes and forces 1. Introduction Classical nonequilibrium thermodynamics is an important field of modern physics that was developed for more than a century [1–5]. It is fundamentally based on thermodynamics and statistical physics (including kinetic theory and theory of random processes) and is widely applied in biophysics, geophysics, chemistry, economics, etc.
  • Thermodynamics the Study of the Transformations of Energy from One Form Into Another

    Thermodynamics the Study of the Transformations of Energy from One Form Into Another

    Thermodynamics the study of the transformations of energy from one form into another First Law: Heat and Work are both forms of Energy. 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 Second Law: Entropy is a measure of disorder; Entropy of an isolated system Increases in any spontaneous process. OR This law also predicts that the entropy of an isolated system always increases with time. Third Law: The entropy of a perfect crystal approaches zero as temperature approaches absolute zero. ©2010, 2008, 2005, 2002 by P. W. Atkins and L. L. Jones ©2010, 2008, 2005, 2002 by P. W. Atkins and L. L. Jones A Molecular Interlude: Internal Energy, U, from translation, rotation, vibration •Utranslation = 3/2 × nRT •Urotation = nRT (for linear molecules) or •Urotation = 3/2 × nRT (for nonlinear molecules) •At room temperature, the vibrational contribution is small (it is of course zero for monatomic gas at any temperature). At some high temperature, it is (3N-5)nR for linear and (3N-6)nR for nolinear molecules (N = number of atoms in the molecule. Enthalpy H = U + PV Enthalpy is a state function and at constant pressure: ∆H = ∆U + P∆V and ∆H = q At constant pressure, the change in enthalpy is equal to the heat released or absorbed by the system. Exothermic: ∆H < 0 Endothermic: ∆H > 0 Thermoneutral: ∆H = 0 Enthalpy of Physical Changes For phase transfers at constant pressure Vaporization: ∆Hvap = Hvapor – Hliquid Melting (fusion): ∆Hfus = Hliquid –
  • Lecture 15 November 7, 2019 1 / 26 Counting

    Lecture 15 November 7, 2019 1 / 26 Counting

    ...Thermodynamics Positive specific heats and compressibility Negative elastic moduli and auxetic materials Clausius Clapeyron Relation for Phase boundary \Phase" defined by discontinuities in state variables Gibbs-Helmholtz equation to calculate G Lecture 15 November 7, 2019 1 / 26 Counting There are five laws of Thermodynamics. 5,4,3,2 ... ? Laws of Thermodynamics 2, 1, 0, 3, and ? Lecture 15 November 7, 2019 2 / 26 Third Law What is the entropy at absolute zero? Z T dQ S = + S0 0 T Unless S = 0 defined, ratios of entropies S1=S2 are meaningless. Lecture 15 November 7, 2019 3 / 26 The Nernst Heat Theorem (1926) Consider a system undergoing a pro- cess between initial and final equilibrium states as a result of external influences, such as pressure. The system experiences a change in entropy, and the change tends to zero as the temperature char- acterising the process tends to zero. Lecture 15 November 7, 2019 4 / 26 Nernst Heat Theorem: based on Experimental observation For any exothermic isothermal chemical process. ∆H increases with T, ∆G decreases with T. He postulated that at T=0, ∆G = ∆H ∆G = Gf − Gi = ∆H − ∆(TS) = Hf − Hi − T (Sf − Si ) = ∆H − T ∆S So from Nernst's observation d (∆H − ∆G) ! 0 =) ∆S ! 0 As T ! 0, observed that dT ∆G ! ∆H asymptotically Lecture 15 November 7, 2019 5 / 26 ITMA Planck statement of the Third Law: The entropy of all perfect crystals is the same at absolute zero, and may be taken to be zero. Lecture 15 November 7, 2019 6 / 26 Planck Third Law All perfect crystals have the same entropy at T = 0.
  • Ch. 3. the Third Law of Thermodynamics (Pdf)

    Ch. 3. the Third Law of Thermodynamics (Pdf)

    3-1 CHAPTER 3 THE THIRD LAW OF THERMODYNAMICS1 In sharp contrast to the first two laws, the third law of thermodynamics can be characterized by diverse expression2, disputed descent, and questioned authority.3 Since first advanced by Nernst4 in 1906 as the Heat Theorem, its thermodynamic status has been controversial; its usefulness, however, is unquestioned. 3.1 THE HEAT THEOREM The Heat Theorem was first proposed as an empirical generalization based on the temperature dependence of the internal energy change, ∆U, and the Helmholtz free energy change, ∆A, for chemical reactions involving condensed phases. As the absolute temperature, T, approaches zero, ∆U and ∆A by definition become equal, but The Heat Theorem stated that d∆U/dT and d∆A/dT also approach zero. These derivatives are ∆Cv and -∆S respectively. The statement that ∆Cv equals zero would attract little attention today in view of the abundance of experimental and theoretical evidence showing that the heat capacities of condensed phases approach zero as zero absolute temperature is approached. However, even today the controversial and enigmatic aspect of The Heat Theorem is the equivalent statement 1 Most of this chapter is taken from B.G. Kyle, Chem. Eng. Ed., 28(3), 176 (1994). 2 For a sampling of expressions see E. M. Loebl, J. Chem. Educ., 37, 361 (1960). 3 For extreme positions see E. D. Eastman, Chem. Rev., 18, 257 (1936). 4 All of Nernst's work in this area is covered in W. Nernst, The New Heat Theorem; Dutton: New York, 1926. 3-2 lim ∆S = 0 (3-1) T → 0 In 1912 Nernst offered a proof that the unattainability of zero absolute temperature was dictated by the second law of thermodynamics and was able to show that Eq.
  • MODULE 11: GLOSSARY and CONVERSIONS Cell Engines

    MODULE 11: GLOSSARY and CONVERSIONS Cell Engines

    Hydrogen Fuel MODULE 11: GLOSSARY AND CONVERSIONS Cell Engines CONTENTS 11.1 GLOSSARY.......................................................................................................... 11-1 11.2 MEASUREMENT SYSTEMS .................................................................................. 11-31 11.3 CONVERSION TABLE .......................................................................................... 11-33 Hydrogen Fuel Cell Engines and Related Technologies: Rev 0, December 2001 Hydrogen Fuel MODULE 11: GLOSSARY AND CONVERSIONS Cell Engines OBJECTIVES This module is for reference only. Hydrogen Fuel Cell Engines and Related Technologies: Rev 0, December 2001 PAGE 11-1 Hydrogen Fuel Cell Engines MODULE 11: GLOSSARY AND CONVERSIONS 11.1 Glossary This glossary covers words, phrases, and acronyms that are used with fuel cell engines and hydrogen fueled vehicles. Some words may have different meanings when used in other contexts. There are variations in the use of periods and capitalization for abbrevia- tions, acronyms and standard measures. The terms in this glossary are pre- sented without periods. ABNORMAL COMBUSTION – Combustion in which knock, pre-ignition, run- on or surface ignition occurs; combustion that does not proceed in the nor- mal way (where the flame front is initiated by the spark and proceeds throughout the combustion chamber smoothly and without detonation). ABSOLUTE PRESSURE – Pressure shown on the pressure gauge plus at- mospheric pressure (psia). At sea level atmospheric pressure is 14.7 psia. Use absolute pressure in compressor calculations and when using the ideal gas law. See also psi and psig. ABSOLUTE TEMPERATURE – Temperature scale with absolute zero as the zero of the scale. In standard, the absolute temperature is the temperature in ºF plus 460, or in metric it is the temperature in ºC plus 273. Absolute zero is referred to as Rankine or r, and in metric as Kelvin or K.
  • Bsc Chemistry

    Bsc Chemistry

    Subject Chemistry Paper No and Title 10: Physical Chemistry –III (Classical Thermodynamics, Non-Equilibrium Thermodynamics, Surface Chemistry, Fast Kinetics) Module No and Title 12: Thermodynamic criteria for non-equilibrium states Module Tag CHE_P10_M12 CHEMISTRY Paper No. 10: Physical Chemistry –III (Classical Thermodynamics, Non-Equilibrium Thermodynamics, Surface Chemistry, Fast Kinetics) Module No. 12: Thermodynamic criteria for nonequilibrium states TABLE OF CONTENTS 1. Learning Outcomes 2. Introduction 3. Difference between equilibrium and non-equilibrium thermodynamics 4. Postulates of irreversible thermodynamics 5. Non equilibrium state variables 6. Basic concepts 6.1 Zeroth law of thermodynamics 6.2 First law of thermodynamics 6.3 Second law of thermodynamics 6.4 Third law of thermodynamics 7. Summary CHEMISTRY Paper No. 10: Physical Chemistry –III (Classical Thermodynamics, Non-Equilibrium Thermodynamics, Surface Chemistry, Fast Kinetics) Module No. 12: Thermodynamic criteria for nonequilibrium states 1. Learning Outcomes After studying this module you shall be able to: Know the significance of irreversible thermodynamics Differentiate between equilibrium and non-equilibrium thermodynamics. Learn postulates of non-equilibrium thermodynamics. Know about different laws of thermodynamics (first, second and third) laws. 2. Introduction In classical thermodynamics, we have seen time dependent variation of thermodynamic quantities such as is internal energy (U), enthalpy (H), entropy (S),Gibb’s free energy (G) etc. are not considered. Classical thermodynamics deals with transitions from one equilibrium state to another brought about by different mechanical or chemical methods. Non equilibrium thermodynamics is that branch of thermodynamics that deals with the system which are not in thermodynamic equilibrium. But such systems can be described by non-equilibrium state variables which represent an extrapolation of variables used to specify system in thermodynamic equilibrium.
  • Section 5 Further Thermodynamics

    Section 5 Further Thermodynamics

    Section 5 Further Thermodynamics 5.1 Phase equilibrium 5.1.1 Conditions for equilibrium coexistence It is an observed fact that the physical state of a system can sometimes be changed dramatically when its external conditions are changed only slightly. Thus ice melts when the temperature is increased from slightly below 0°C to slightly above this temperature. Different physical states of the same substance are referred to as phases and the study of transitions between phases is one of the most interesting problems in statistical thermodynamics. This is partly because the question of predicting when and how a phase transition will occur is still not a fully solved problem. There is the further point that a comprehensive understanding of phase transition phenomena might have wider application to such things as the outbreak of a war or a stock market crash. Very generally, phase transitions are due to interactions between the constituent particles of a system. The model-dependence of the behavior would suggest that full understanding can only come from a statistical mechanical study, not from thermodynamics. However there are many aspects of phase transitions which seem to be general and common to many systems. Macroscopic thermodynamics is of help here since it is model-independent and it connects seemingly unrelated properties of the system. This frees us to concentrate on the few thermodynamic variables of the system instead of getting bogged down in the microscopic detail. We start by considering the conditions for equilibrium to exist between two phases of the same substance — such as ice and water, for example.
  • Laws of Thermodynamics

    Laws of Thermodynamics

    Advanced Instructional School on Mechanics, 5 - 24, Dec 2011 Special lectures Laws of Thermodynamics K. P. N. Murthy School of Physics, University of Hyderabad Dec 15, 2011 K P N Murthy (UoH) Thermodynamics Dec 15, 2011 1 / 126 acknowledgement and warning acknowledgement: Thanks to Prof T Amaranath and V D Sharma for the invitation warning: I am going to talk about the essential contents of the laws of thermodynamics, tracing their origin, and their history The Zeroth law, the First law the Second law .....and may be the Third law, if time permits I leave it to your imagination to connect my talks to the theme of the School which is MECHANICS. K P N Murthy (UoH) Thermodynamics Dec 15, 2011 2 / 126 Each law provides an experimental basis for a thermodynamic property Zeroth law= ) Temperature, T First law= ) Internal Energy, U Second law= ) Entropy, S The earliest was the Second law discovered in the year 1824 by Sadi Carnot (1796-1832) Sadi Carnot Helmholtz Rumford Mayer Joule then came the First law - a few decades later, when Helmholtz consolidated and abstracted the experimental findings of Rumford, Mayer and Joule into a law. the Zeroth law arrived only in the twentieth century, and I think Max Planck was responsible for it K P N Murthy (UoH) Thermodynamics Dec 15, 2011 3 / 126 VOCALUBARY System: The small part of the universe under consideration: e.g. a piece of iron a glass of water an engine The rest of the universe (in which we stand and make observations and measurements on the system) is called the surroundings a glass of water is the system and the room in which the glass is placed is called the surrounding.