"One simple statement of the law is that heat always moves from hotter objects to colder objects (or 'downhill'), unless energy in some form is supplied to reverse the direction of heat flow."
The law that states that the total entropy of a closed system will never decrease over time. It also includes the concepts of reversible and irreversible processes, as well as the Carnot cycle.
Introduction to thermodynamics: It is an area of physics that deals with the relationship between heat, energy, and work. Includes the first and second laws of thermodynamics.
The Second Law of Thermodynamics: It states that the total amount of entropy in a closed system always increases over time.
Entropy: It is a measure of the disorder or randomness of a system. Higher entropy means higher disorder.
Internal Energy and Enthalpy: They are state functions that describe the energy of a system. Internal energy is the sum of all the energy, while enthalpy is the sum of internal energy and pressure times volume.
Heat and Work: These are the two mechanisms by which energy is transferred into or out of a system.
The Carnot cycle: It is a theoretical cycle that is the most efficient way to convert heat into work.
The Thermodynamic State Function: State functions are properties of a system that depend only on the current state of the system, not on how it got there.
Gibbs free energy: It is a measure of the amount of energy available to do useful work in a system.
Phase Equilibria: It is the relationship between the phases of a substance at equilibrium.
Equilibrium constant and reaction spontaneity: The equilibrium constant of a reaction is a measure of how spontaneous it is.
Standard heat of formation and reaction: It is the amount of heat released or absorbed when a compound is formed or a reaction occurs under standard conditions.
Chemical potential and activity: Chemical potential is the energy needed to add a mole of a substance to a system. Activity is a measure of the effective concentration of a substance in a mixture.
Thermodynamic cycles: It is a series of thermodynamic processes that form a closed loop.
The Clausius-Clapeyron Equation: It is an equation that relates the vapor pressure of a substance to its temperature and enthalpy of vaporization.
The Joule-Thomson Effect: It is the cooling or heating of a gas when it is forced through a valve or porous plug at constant enthalpy.
Thermochemistry: It is the field of chemistry that deals with the relationships between chemical reactions and energy changes.
Electrochemistry: It is the study of the relationship between chemical reactions and electrical energy.
Statistical Thermodynamics: It is a branch of thermodynamics that uses statistical methods to study the behavior of large groups of particles.
Microscopic vs. Macroscopic view of thermodynamics: A macroscopic view of thermodynamics uses large-scale measurements, while a microscopic view uses atomic and subatomic particles.
The Three Laws of Thermodynamics: The first law states that energy is conserved. The second law states that entropy always increases. The third law states that the entropy of a perfect crystal at absolute zero is zero.
Clausius Statement: Heat cannot flow from a colder body to a hotter body without the expenditure of external work.
Kelvin-Planck Statement: It is impossible to construct a device that operates in a cyclic process, producing no other effect than the extraction of heat from a single thermal reservoir and the conversion of this heat into work.
Entropy Statement: The entropy of an isolated system always tends to increase with time, approaching a maximum value at equilibrium.
Gibbs Free Energy Statement: The total change in free energy of a system and its surroundings is always negative in a spontaneous process, while it is positive in a non-spontaneous process.
Carathéodory’s Principle: It is impossible to construct a device that transfers heat from a single body and performs equivalent or greater amount of work, using only cyclical changes.
"Not all heat energy can be converted into work in a cyclic process."
"The second law of thermodynamics in other versions establishes the concept of entropy as a physical property of a thermodynamic system."
"It can be used to predict whether processes are forbidden despite obeying the requirement of conservation of energy as expressed in the first law of thermodynamics and provides necessary criteria for spontaneous processes."
"The entropy of isolated systems left to spontaneous evolution cannot decrease, as they always arrive at a state of thermodynamic equilibrium where the entropy is highest at the given internal energy."
"An increase in the combined entropy of the system and surroundings accounts for the irreversibility of natural processes."
"The second law was an empirical finding that was accepted as an axiom of thermodynamic theory."
"Statistical mechanics provides a microscopic explanation of the law in terms of probability distributions of the states of large assemblies of atoms or molecules."
"The first formulation, which preceded the proper definition of entropy and was based on caloric theory, is Carnot's theorem, formulated by the French scientist Sadi Carnot."
"Carnot's theorem, formulated by the French scientist Sadi Carnot, who in 1824 showed that the efficiency of conversion of heat to work in a heat engine has an upper limit."
"The first rigorous definition of the second law based on the concept of entropy came from German scientist Rudolf Clausius in the 1850s."
"Heat can never pass from a colder to a warmer body without some other change, connected therewith, occurring at the same time."
"The second law of thermodynamics allows the definition of the concept of thermodynamic temperature."
"The concept of thermodynamic temperature relies also on the zeroth law of thermodynamics."
"The second law of thermodynamics provides necessary criteria for spontaneous processes."
"The second law of thermodynamics in other versions establishes the concept of entropy as a physical property of a thermodynamic system."
"Heat always moves from hotter objects to colder objects (or 'downhill'), unless energy in some form is supplied to reverse the direction of heat flow."
"Not all heat energy can be converted into work in a cyclic process."
"The increase in the combined entropy of system and surroundings accounts for the irreversibility of natural processes."
"The entropy of isolated systems left to spontaneous evolution cannot decrease."