What is thermal equilibrium ? Which four equilibrium should be reached in the state of thermal equi

Thermal equilibrium within a single system. If there is no heat transfer between the parts that make up a single system, and there is no heat transfer with the outside world, the system is in thermal equilibrium. At this time, the temperature of all parts of the system is equal and equal to the outside temperature.

In thermal equilibrium, there is no heat exchange between the parts of the object and between the object and the outside world. In thermal engineering and chemistry, if the heat absorbed and emitted by an object at the same time happens to cancel each other, the object is also said to be in thermal equilibrium. Thermal equilibrium: The thermal equilibrium between two systems.

A system in an arbitrary equilibrium state, in the absence of macroscopic work, relies on the direct interaction of the system with the outside world to change the state of the system called thermal contact (or heat exchange). When two thermodynamic systems are in thermal contact, the original equilibrium state of the system will generally change; After a sufficiently long period of time, the heat exchange stops; At this point, the two systems can be considered to be in thermal equilibrium. If the state of the two systems does not change when they are in thermal contact, it means that the two systems are already in thermal equilibrium with each other.

It can be considered that two systems that are in thermal equilibrium with each other have the same degree of heat and cold, and the temperature is equal. Thermal equilibrium between the three systems, if there are three systems A, B, and C in an arbitrarily determined equilibrium state, and systems A and B are adiabatic from each other. Let A and B be in thermal contact with System C at the same time, and after a long enough period of time, both A and B will reach thermal equilibrium with C.

At this time, A and B are no longer adiabatic and are in thermal contact with each other, and the experiment proves that the states of A and B do not change, that is, A and B are also in thermal equilibrium. This experiment shows that if two thermodynamic systems are in thermal equilibrium with the third thermodynamic system each, they must also be in thermal equilibrium with each other. This experimental conclusion is called the transitivity of thermal equilibrium, or the law of thermal equilibrium.

The law of thermal equilibrium, the law of thermal equilibrium is a basic experimental law in thermodynamics, and its significance lies in the fact that it is the basis for scientifically defining the concept of temperature, which is the use of a thermometer.

The basis for measuring the temperature.

In thermodynamics, temperature, internal energy, and entropy are the three basic state functions, and internal energy is determined by the first law of thermodynamics.

Positive; Entropy is determined by the second law of thermodynamics.

Positive; Whereas, temperature is determined by the law of thermal equilibrium. So the law of thermal equilibrium is as follows.

The first and second laws are also the basic experimental laws of thermodynamics, and their importance is no less than that of thermodynamics.

1. The second law, but because people are fully aware of thermodynamics.

The importance of this law was only realized after the second law, so the famous British physicist called it the zeroth law of thermodynamics.

Thermal equilibrium Thermal equilibrium calculation q discharge = q suction. First, find out what ways the system absorbs heat, and then quantitatively analyze; Then find out what ways the system releases heat, and analyze it quantitatively; Finally, the formula of the thermal equilibrium q discharge = q absorption of the system is used to solve the heat absorbed or released by the system through a certain way. Thermal balance calculations are often used in areas that require thermal analysis, such as heat and mass transfer, refrigeration and heating, and boiler calculations.

In the absence of external influences, the macroscopic properties of a thermodynamic system do not change with time. The so-called external influence refers to the work or heat transfer of the system by the outside world. The equilibrium state cannot be understood simply as a state that does not change with time.

For example, if the two ends of a metal rod are always in contact with boiling water and ice water, and the heat is constantly transferred from one end to the other, the temperature of the rod is different but does not change over time, but the rod is not in equilibrium. Unlike mechanical equilibrium, which is purely stationary, the thermal equilibrium state is thermodynamic equilibrium, in which the molecules in the system are still in random thermal motion, but the average effect does not change with time. Experiments show that in the absence of external influences, a thermodynamic system will inevitably tend to thermal equilibrium after a long enough time.

When two or more thermodynamic systems come into contact with each other, they will inevitably tend to a common equilibrium state as long as they are long enough and there are no external influences. This is the experimental basis for the introduction of the concept of thermal equilibrium. If two thermodynamic systems are in thermal equilibrium with the third system, they must also be in thermal equilibrium with each other.

This experimental law, known as the zeroth law of thermodynamics, shows that thermal equilibrium is transitive, and that the thermal equilibrium state is the basis for scientifically defining the concept of temperature and the basis for measuring temperature with a thermometer.

The heat balance of the body is the heat balance when the heat production and heat dissipation of the animal are equal. Mammals and poultry, as homeothermic animals, must balance heat dissipation and heat production in order to maintain a relatively constant body temperature and ensure that the organs and tissues of the body perform normal physiological functions. The electrons in thermal equilibrium carrier semiconductors are in a certain energy band, but only the electrons in the conduction band and the holes in the valence band can participate in conduction, which are called carriers.

Under the condition that the temperature is constant, the number of electron-hole logarithms generated per unit time is equal to the number of electron-hole logarithms that recombine and disappear per unit time, and the electron-hole concentration in the semiconductor remains constant, which is called thermal equilibrium.

The amount of heat absorbed and emitted is equal, which is called thermal equilibrium. Under the condition of isolation from external influences, if objects A and B reach thermal equilibrium with object C in a definite state, respectively, then objects A and B are also thermally balanced with each other. With the introduction of the zeroth law of thermodynamics, the standard of "temperature is the same" is no longer limited to being placed directly together, but is a transmissible standard, which is also the principle of people using thermometers to measure temperature.

Equilibrium state A system in which the properties of the system do not change over time when it is completely isolated from environmental influences. Only when the system is in equilibrium does the state function have a uniquely determined value.

There are three conditions that must be met for the system to be in equilibrium:

Thermal equilibrium: the temperature of each part is equal;

Force balance: the pressure of each part is equal;

Chemical equilibrium and phase equilibrium: the concentration is homogeneous and the composition does not change with time.

Dynamic equilibrium.

Explanation of thermal equilibrium.

A state in which there is no heat transfer between the internal parts of an object, and there is no heat exchange between the object and the outside world. In thermal equilibrium, the temperature inside the object is equal everywhere and equal to the outside temperature.

Word decomposition Explanation of heat heat (hot) è high temperature, feeling high temperature, as opposed to "cold" : hot water. Tropic.

Burn the beam to let it be hot. Heat. The water is in dire straits (a metaphor for the people's living situation, which is abnormal, difficult, and painful).

Body fever: fever. Raise the temperature:

Fomentation. Affectionate: Warm-hearted.

Enthusiastic. Zeal. Fervent.

Blood. Love scum teasing. Explanation of Balance The weight of the two ends of the scale is equal, and the two things are flush like a balance.

In physiology, the relationship between the synthesis and decomposition of a particular nutrient is greater than that of catabolism, which is called positive equilibrium, two or more opposing forces or processes.

Thermal equilibrium is when the temperature between the objects is equal and there is no longer a net heat transfer. However, satisfying the thermal equilibrium does not guarantee that the object is in equilibrium. As an example, let's say we have two gases in a closed container that start with different temperatures and pressures.

When they reach thermal equilibrium, their temperature is equal to that of the trace, but they still do not reach equilibrium. Because in this case, the particles of each gas can still move freely in the container, collide at the same time, and there is still an unbalanced chemical reaction of spike change. Only when all these processes reach a steady state can we call the system equilibrium state.

Another example is the atmosphere. There are many complex nonlinear processes in the atmosphere, including radiation, convection, and transport. Although different parts of the atmosphere may reach thermal equilibrium, the entire atmosphere is still in a state of flux, such as the appearance of weather phenomena, and therefore cannot be described as equilibrium.

Thermal equilibrium is only one aspect of the system reaching equilibrium, but not the whole story. For a system to truly reach equilibrium, other factors such as mechanical, chemical, and thermodynamic equilibrium need to be considered.

The equilibrium state refers to the state of the system, that is, the state in which the macroscopic properties of each part of the system do not change for a long time without the influence of the outside world (referring to the surrounding environment related to the system), so the equilibrium state is just an idealized concept. Thermal equilibrium is a state in which heat is not transferred within the same object or between several objects that can exchange heat with each other, and neither heat migration nor phase transformation of matter occurs, but the same temperature.

From the micro**, due to the non-stop thermal movement of the molecules that make up the system, the microscopic quantities change rapidly with time, and only the statistical average of the corresponding microscopic quantities remains unchanged. So, the thermodynamic equilibrium state is a dynamic equilibrium called thermodynamic equilibrium. The state parameter of dynamic equilibrium is not absolute, and a slight deviation from the equilibrium value still occurs, which is called fluctuation.

The analysis shows that in a system composed of a large number of particles, the fluctuations are very small, and its relative strength is inversely proportional to the square root of the number of particles, so that this deviation is completely negligible in macroscopic observations. Only special problems, such as molecular scattering of light in the atmosphere and critical opalescence phenomena in liquids, must consider the effects of fluctuations. The equilibrium state is an idealized concept, because there is no such thing as an isolated system in a practical problem that is completely free from external influences.

However, if the rate of change of external conditions is slow enough relative to the rate at which the system moves from non-equilibrium to equilibrium, the concept of equilibrium is a reasonable abstraction and approximation of the actual situation. For example, in a general cylinder, the piston moves at a rate of about a few meters per second, and experiments show that the rate at which the pressure in the gas tends to equilibrium at room temperature is about a few hundred meters per second, so the state of the gas in the cylinder can be approximated to the equilibrium state at every moment of piston movement. For more knowledge, please pay attention to the high school physics course of Beijing New Oriental Middle School, which I believe can help you.

The equilibrium state, in a narrow sense, refers to a state of mechanical equilibrium, in which various forces cancel each other out, and the total force is zero. Broadly speaking, it refers to various equilibrium states, including thermal equilibrium, population equilibrium, and mechanical equilibrium.

Thermal equilibrium refers to the fact that the temperature of an object or system is stable and will not change due to heat absorption or exothermy.

Balanced; There is no pressure difference at both ends of the machine seal.