This chapter introduces the foundational concepts and terminology needed for the study of thermodynamics, including systems, surroundings, state variables, and the classification of physical systems. It explains the physical meaning and measurement of pressure, temperature, energy, and work while introducing important concepts such as the Zeroth Law of Thermodynamics and the Kelvin temperature scale. The chapter concludes by developing mathematical expressions for mechanical work and gas expansion work, including the important limiting case of reversible expansion.
Work is a form of energy transfer that occurs when an object moves against a resisting force. Students should be able to use equations for mechanical displacement work as well as pressure-volume work for expanding gases, including the integral expressions used for reversible expansions and variable forces.
The Zeroth Law establishes the concept of temperature through thermal equilibrium. Students should understand that if two systems are each in thermal equilibrium with a third system, they must also be in thermal equilibrium with one another and therefore share the same temperature.
Temperature can be expressed using the Fahrenheit, Celsius, and Kelvin scales. Students should be able to convert between these scales and understand that the Kelvin scale is an absolute temperature scale whose zero point corresponds to absolute zero.
Thermodynamics begins by defining a system as the portion of the universe under study and the surroundings as everything outside that system. Students should be able to distinguish between open, closed, and isolated systems based on whether matter and energy can cross the system boundary.
Specific heat describes how much energy is required to change the temperature of a substance. Students should be able to perform calculations involving heat transfer and explain how differences in specific heat affect the temperature changes that occur when substances absorb or release energy.