Chemical thermodynamics


In chemistry , most of the elements and compounds are dynamic aside they are influenced by other factors. One of them would be thermodynamics, it refers to the study of the flow of energy; more precisely, it is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the given system. Chemical thermodynamics includes not only laboratory measurements of different thermodynamic properties, but also the application of mathematical methods to the study of chemical questions and the spontaneity of processes. This article is the brief description of system, surroundings, state and properties of   system , equilibrium and internal energy.


Energy Transformations

Energy transformation entails heat and it's effects on a significant number of chemical and physical processes. Work is done when a force is used to move an object. Energy is, therefore, the capacity for doing work. You should recall that energy is weightless, odorless, and tasteless. Chemical potential energy refers to the energy stored within the structural units of chemical substances. Different substances store a different amount of energy. The type of atoms and their arrangement in the substances determine the amount of energy stored in the substance. Heat is normally denoted by q which is the amount of energy transferred from one substance to another due to the temperature difference between the two materials. The changes caused by heat can help us in detecting it because heat can be identified by either sense of touch or use of instruments. The rise in temperature from an object can precisely be used to demonstrate the presence of heat in the object. Usually, heat flows from a warmer object to a cooler object. If 2 objects remain in contact, heat will flow from the warmer object to the cooler object until the temperature of both objects become the same


System and Surroundings

The system refers to the part of the universe on which we focus our attention. The surrounding includes everything else in the universe. You should note that the system and it`s surrounding constitute the universe. So, System + Surrounding = Universe. There are three types of systems commonly in practice are the open system, closed system and an isolated system. The open system refers to a system in which the flow of mass and heat is possible. The closed system refers to a system in which only the flow of heat is possible but not mass. An isolated system is a system in which neither mass nor heat can flow in or out.


State and properties of a system

The four variables; temperature, number of moles, volume and pressure describes the condition of a system. Altering any of the mentioned variables will make the state of the system to shift. The properties of a given system can be grouped as either extensive or intensive. An extensive property of a system mainly relies on the mass and number of particles in the system. A good example is total energy and volume. Intensive properties of a system rely majorly on the concentration but are independent of mass and the total number of particles. Examples include; pressure, density and the reflective index.


State functions

State functions refer to thermodynamic functions which rely only on the initial and final states of the system.  The path function, on the other hand, refers to the functions which majorly depend on the path followed in the process of shifting from one state to another.



In thermodynamics, a system is said to be in equilibrium if the four variables, temperature, number of moles, volume and pressure, remain constant and the system satisfies the three types of equilibrium. The three main types of thermodynamic equilibrium are the Mechanical equilibrium, Thermal equilibrium and chemical equilibrium. Mechanical equilibrium is the type of equilibrium in which there I no mechanical motion and both the pressure and volume of the system is kept constant. Thermal equilibrium is another type of equilibrium in which there is no flow of heat, and the temperature of the system doesn't vary with time. Chemical equilibrium is the type of equilibrium in which the rate of forwarding reaction is equal to the rate of backward reaction in any given chemical reaction.


Internal energy

Internal energy refers to the sum of all the components of the energy of the system due to the internal factors. Internal energy is usually denoted by U, but other authors also use E. The internal energy of the system is a function of temperature since it depends on the kinetic energy of the gas under study. The internal energy is said to be a state function since it majorly depends on temperature.




  1. What is thermodynamics in chemistry?

  2. Define system in thermodynamics and mention its types.

  3. Explain the states of equilibrium in thermodynamics.

  4. Mention 4 important factors of chemical thermodynamics.





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