Thermodynamics

chemical energetics 
          It is the branch of chemistry which deals with the study of quantitative relationships between heat and other forms of energies.
some thermodynamics terms 
system :
          It is a specific part so the universe selected for study
surrounding:
          The remaining part of the universe excepted the system is called surrounding
boundary:
          The region separating the system from the surrounding is called boundary
          If a substance is heated in a test tube, then the substance forms the system, walls of the tube from the boundary and everything else is the surrounding
types of system-
         
open system:
            A system which can exchange matter as well energy with the surrounding forms an open system
closed system:
            A system which can exchange energy but not the matter with the surrounding is called a closed system
            when water is heated in a closed beaker, we see the transfer of heat from surrounding burner to the system but the matter is not exchanged
isolated system:                                                                                               A system that can neither exchange mass nor energy with the surroundings is called an isolated system.
homogeneous system:                                                                                     It is the one in which the constituents present are in the same phase and its composition is uniform throughout.                                        Example: miscible liquids and the mixture of gases.
heterogeneous system:                                                                                   It is the one in which the constituent s present is not in the same phase and the composition is not uniform throughout.
              Example: the mixture of two or more solids, immiscible liquids, insoluble salt in a. liquid etc.                                                  Internal energy (u):                                                                                                 The total energy stored in a system under a given set of conditions is called its internal energy.                                            Internal energy change: Internal energy change is the heat evolved or absorbed in a reaction at constant temperature and volume.          
Characteristic of internal energy :                                                             (i) As its value depends upon the quantity of matter present in the system, it is an extensive property.                                                      (ii) Its value does not depend upon the path followed.                       (iii) It is a state function. Its value depends upon the initial and the final state of the system.