# Lecture in The Laws of Thermodynamics | Giancoli Physics

(Last Updated On: March 21, 2020)

### Lesson Objectives – the students should be able to:

• Explain what is meant by a physical system and distinguish between an open system and a closed system.
• State the first law of thermodynamics and use this law to solve problems.
• Distinguish between an isothermal process, isobaric process, isochoric process and adiabatic process and draw a PV diagram for each process.
• Calculate the work done by a gas from a PV diagram. Use the equations for an ideal gas and for the internal energy of a gas to calculate the change in internal energy of a gas and the heat added or removed during a thermodynamic process.
• Calculate the amount of heat which must be added or removed to change the temperature of a gas held in a closed container under conditions of constant volume or constant pressure.
• Write from memory and explain the meaning of three equivalent ways of stating the second law of thermodynamics.
• Use the first and second laws of thermodynamics to solve problems involving a Carnot engine.
• Distinguish between a reversible process and an irreversible process. Give examples of each type of process.
• Determine the change in entropy for a system in which the thermodynamic process is either reversible or irreversible.
• Distinguish between macrostate and microstate and solve problems involving the statistical interpretation of entropy.

### Summary of Chapter 15

• First law of thermodynamics:
• Isothermal process: temperature is constant.
• Adiabatic process: no heat is exchanged.
• Work done by gas at constant pressure:
• Heat engine changes heat into useful work; needs temperature difference.
• Efficiency of a heat engine:
• Upper limit on efficiency:
• Refrigerators and air conditioners do work to extract heat from a cooler region and send it to a warmer region:
• A heat pump is similar:
• Second law of thermodynamics:
• heat flows spontaneously from a hot object to a cold one, but not the reverse
• a given amount of heat cannot be changed entirely to work
• natural processes tend to increase entropy.
• Change in entropy:
• Entropy is a measure of disorder.
• As time goes on, less and less energy is available to do useful work.

### Units of Chapter 15 – Keywords

• The First Law of Thermodynamics
• Thermodynamic Processes and the First Law
• Human Metabolism and the First Law
• The Second Law of Thermodynamics – Introduction
• Heat Engines
• Refrigerators, Air Conditioners, and Heat Pumps
• Entropy and the Second Law of Thermodynamics
• Order to Disorder
• Unavailability of Energy; Heat Death
• Evolution and Growth; “Time’s Arrow”
• Statistical Interpretation of Entropy and the Second Law
• Thermal Pollution and Global Warming