College Physics

# Introduction to Thermodynamics

College PhysicsIntroduction to Thermodynamics

Figure 15.1 A steam engine uses heat transfer to do work. (credit: Gerald Friedrich, Pixabay)

### Chapter Outline

15.1 The First Law of Thermodynamics
• Define the first law of thermodynamics.
• Describe how conservation of energy relates to the first law of thermodynamics.
• Identify instances of the first law of thermodynamics working in everyday situations, including biological metabolism.
• Calculate changes in the internal energy of a system, after accounting for heat transfer and work done.
15.2 The First Law of Thermodynamics and Some Simple Processes
• Describe the processes of a simple heat engine.
• Explain the differences among the simple thermodynamic processes—isobaric, isochoric, isothermal, and adiabatic.
• Calculate total work done in a cyclical thermodynamic process.
15.3 Introduction to the Second Law of Thermodynamics: Heat Engines and Their Efficiency
• State the expressions of the second law of thermodynamics.
• Calculate the efficiency and carbon dioxide emission of a coal-fired electricity plant, using second law characteristics.
• Describe and define the Otto cycle.
15.4 Carnot’s Perfect Heat Engine: The Second Law of Thermodynamics Restated
• Identify a Carnot cycle.
• Calculate maximum theoretical efficiency of a nuclear reactor.
• Explain how dissipative processes affect the ideal Carnot engine.
15.5 Applications of Thermodynamics: Heat Pumps and Refrigerators
• Describe the use of heat engines in heat pumps and refrigerators.
• Demonstrate how a heat pump works to warm an interior space.
• Explain the differences between heat pumps and refrigerators.
• Calculate a heat pump’s coefficient of performance.
15.6 Entropy and the Second Law of Thermodynamics: Disorder and the Unavailability of Energy
• Define entropy and calculate the increase of entropy in a system with reversible and irreversible processes.
• Explain the expected fate of the universe in entropic terms.
• Calculate the increasing disorder of a system.
15.7 Statistical Interpretation of Entropy and the Second Law of Thermodynamics: The Underlying Explanation
• Identify probabilities in entropy.
• Analyze statistical probabilities in entropic systems.

Heat transfer is energy in transit, and it can be used to do work. It can also be converted to any other form of energy. A car engine, for example, burns fuel for heat transfer into a gas. Work is done by the gas as it exerts a force through a distance, converting its energy into a variety of other forms—into the car’s kinetic or gravitational potential energy; into electrical energy to run the spark plugs, radio, and lights; and back into stored energy in the car’s battery. But most of the heat transfer produced from burning fuel in the engine does not do work on the gas. Rather, the energy is released into the environment, implying that the engine is quite inefficient.

It is often said that modern gasoline engines cannot be made to be significantly more efficient. We hear the same about heat transfer to electrical energy in large power stations, whether they are coal, oil, natural gas, or nuclear powered. Why is that the case? Is the inefficiency caused by design problems that could be solved with better engineering and superior materials? Is it part of some money-making conspiracy by those who sell energy? Actually, the truth is more interesting, and reveals much about the nature of heat transfer.

Basic physical laws govern how heat transfer for doing work takes place and place insurmountable limits onto its efficiency. This chapter will explore these laws as well as many applications and concepts associated with them. These topics are part of thermodynamics—the study of heat transfer and its relationship to doing work.

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