What is the first law of thermodynamics and is there no formula

The first law of thermodynamics.

Work: δw δwe δwf

1) The expansion work of δwe P outside DV is positive and the compression work is negative. (2) Non-expansive work δwf xdy

The law of conservation of energy is applied to thermodynamics, which is the first law of thermodynamics. In other words, the first law of thermodynamics is the specific quantitative relationship between the law of energy transformation and conservation in the process of thermal phenomena, that is, the quantitative relationship between internal energy and other forms of energy. This law states that in the process of changing any thermodynamic system from one state to another, part of the heat transferred from the outside to the system is used to increase the internal energy of the system, and the other part is used to do work on the outside of the system.

The numerical expression of the first law of thermodynamics is: δe=w+q, where δe represents the amount of internal energy change of the system, w represents the work done by the outside on the system, and q represents the heat absorbed by the outside world. From the above equation, it can be seen that the increase in the internal energy of the system is equal to the sum of the heat absorbed by the system from the outside and the work done by the outside on the system.

When using this law, it is necessary to pay attention to the symbolic treatment of three quantities: the external work on the system, w takes the positive value, the system does the work externally w takes the negative value, if the volume of the system does not change, then w = 0;The system absorbs heat from the outside, Q takes a positive value, and the system exerts heat from the outside, and Q takes a negative value; When the internal energy of the system increases, δe takes a positive value, and when the internal energy of the system decreases, δe takes a negative value.

In refrigeration technology, the first law of thermodynamics can be used to analyze the quantitative changes of thermal energy and mechanical energy and their distribution relationships in various thermal processes. For example, when applying the first law of thermodynamics to the analysis of the refrigeration cycle, it can be concluded that in the compression refrigeration cycle, the mechanical energy expended plus the amount of cold obtained from the cryogenic heat source must be equal to the amount of heat released by the refrigerant to the cooling water or air in the condenser.

The first law of thermodynamics. Formula MathematicsExpressionsis: u=q+w.

The physical meaning is that under normal circumstances, part of the heat added to the working fluid is consumed for expansion work, and the other part is stored in the working fluid, which increases the internal energy of the working fluid. Heat can be converted into work, and work can also be converted into heat, and when a certain amount of heat disappears, a certain amount of work must be produced; When a certain amount of work is expended, a corresponding amount of heat must be generated.

The first law of thermodynamics is the law of energy conversion and conservation, in which the internal energy and other forms of energy are converted into each other in the process of thermal phenomena.

First Law of Thermodynamics Formula Notes:

The first law of thermodynamics is essentially the same as the law of conservation of energy.

It is equivalent, a universal law that applies to all systems in the macrocosm and microcosm, to all forms of energy.

Since 1850, the law of conservation of energy has been recognized by the scientific community as one of the universal laws of nature.

The Law of Conservation of Energy and Transformation.

It can be expressed as: all substances in nature have energy, and energy has various forms, which can be transformed from one form to another, but in the process of transformation, the total value of energy remains unchanged.

The first law of thermodynamics is a special form of the law of conservation and transformation of energy in the field of thermal phenomena, which is a summary of human experience and one of the most basic laws of thermodynamics.

The formula for the first law of thermodynamics is u=q+w.

The first law of thermodynamics refers to the law of conservation of different forms of energy during transfer and conversion, and the expression is u=q+w. This law has been verified by many physicists such as Meyer and Joule, and involves the law of conservation of energy and transformation in the field of thermal phenomena. It is the basis of thermodynamics and has a wide range of applications in energy, which is the material basis of human social activities.

Thermodynamics, the full name of thermodynamics, is a branch of natural science, which is a discipline that studies the properties of the material system in equilibrium in thermal phenomena and establishes the equilibrium relationship of energy, as well as the mutual elimination and use of the system and the outside world when the state changes.

Engineering thermodynamics is one of the first branches of thermodynamics, which mainly studies the law and application of the mutual conversion between thermal energy, mechanical energy and other energy, and is one of the important basic disciplines of mechanical engineering.

Thermodynamics is an aspect of thermal theory. Thermodynamics is the study of the thermal properties of matter from the point of view of energy conversion, and it reveals the macroscopic laws that are followed when the energy is converted from one form to another.

Thermodynamics is a thermal theory obtained by summarizing the macroscopic phenomena of matter, and does not involve the microstructure of matter and the interaction of microscopic particles. Therefore, it is a phenomenological macroscopic theory with a high degree of reliability and universality. The three laws of thermodynamics are the basic theories of thermodynamics.

The first law of thermodynamics refers to the law of conservation of different forms of energy during transfer and conversion, and the expression is u=q+w. Expression: Heat can be transferred from one object to another, and it can also be converted to and from mechanical energy or other energy, but the total value of the energy remains the same during the conversion process.

Its generalization and essence is the famous law of conservation of energy.

The first law of thermodynamics, its generalization and essence, is the famous law of conservation of energy. Refers to the law of conservation of different forms of energy during transfer and conversion, and the expression is u=q+w. Form of expression:

Heat can be transferred from one object to another and can also be converted to and from mechanical energy or other energy, but the total value of the energy remains the same during the conversion process.

This law has been verified by several physicists such as Meyer Joule. The first law of thermodynamics is the law of conservation and transformation of energy in the field of thermal phenomena. It was only in the middle of the nineteenth century that it was established in the form of scientific laws on the basis of long-term production practice and a large number of scientific experiments.

The first law of thermodynamics is essentially equivalent to the law of conservation of energy, and is a universal law that applies to all systems in the macrocosm and microcosm, and to all forms of energy. Since 1850, the law of conservation of energy has been recognized by the scientific community as one of the universal laws of nature. The law of conservation and transformation of energy can be formulated as:

All matter in nature has energy, and energy comes in various forms that can be transformed from one form to another, but in the process of transformation, the total value of energy remains the same. The first law of thermodynamics is a special form of the law of conservation and transformation of energy in the field of thermal phenomena, which is a summary of human experience and one of the most basic laws of thermodynamics.

The first law of thermodynamics is the basis of thermodynamics, and has a wide range of applications in energy, energy is the material basis of human social activities, the development of society is inseparable from the emergence of high-quality energy and the use of advanced energy technology, the scope of energy resources with the development of science and technology and expand, so the broad development prospects of the first law of thermodynamics will be brighter and brighter.

Understanding of the First Law of Thermodynamics.

Definition: The increase in the internal energy of a thermodynamic system is equal to the sum of the heat transferred to it from the outside and the work done to it by the outside world.

If a system is isolated from the environment, then its internal energy will not change.

Expression: u=w+q

If the internal energy of an object is changed simply by doing work, the change in internal energy can be measured by the amount of work done, then the increase (or decrease) of the internal energy of the object u is equal to the value of the work done by the outside world on the object (or the object on the outside), i.e., u=w

If the internal energy of the object is changed simply by heat transfer, the change of internal energy can be measured by the amount of heat transferred, then the increase (or decrease) of the internal energy of the object u is equal to the value of the heat q absorbed (or released to the outside) by the outside world, that is, u=q

In the process of simultaneous work and heat transfer, the change of the internal energy of the object is determined by both the work done and the heat transferred. In this case, the increment u of the internal energy of the object is equal to the sum of the heat q absorbed from the outside world and the work done to the outside world w. i.e. u=w+q

The idea of calculus: p can be considered to have not changed when v changes minimally.

The work done at a very small change in v can be thought of as an extremely narrow rectangular area with a small change in v as the base edge and the current p as the height.

In other words, the equivalent curve can be seen as a series of right-angled polylines.

1+2 can be proved by the microelement method, da=p*dv, and the two sides are integral.

is the area of 1+2, dw=fdl=pdv, w=integral sign (pdv), and the conclusion can be known according to the geometric meaning of the definite integral.

The formula for physical internal energy is: δu w q, where δu is the amount of change in internal energy, w is the amount of work done by the outside world on the system, and q is the heat absorption of the system (from the external boundary), which is called the common expression of the first law of thermodynamics.

The concept of internal energy is based on a large number of precise thermal work equivalent real dust measurements by Joule and others. The establishment of the concept of energy and internal energy marked the real establishment of the law of energy conversion and conservation (i.e., the first law of thermodynamics).

The first law of thermodynamics.

The sum of the work done by the outside world on the object and the heat absorbed by the object from the outside is equal to the incremental state family of the internal energy of the object.

Formula: Sail Xun u=w+q