Thermodynamics: It is the study of empirical relationships
between heat and energy like potential, kinetic, light, mechanical, etc.
Chemical Energetics: It is the study of
heat and energy changes in chemical reactions and physical processes.
Endothermic Reactions: The reactions in which heat is
absorbed are called endothermic reactions.
Exothermic Reactions: The reactions in which heat is
evolved are called exothermic reactions.
System: A part of the universe under thermodynamic
study is system.
Surroundings: The rest of the universe other than that
selected for thermodynamic study is called surroundings.
First Law of Thermodynamics: Total energy of the
universe is constant. E = mc2
Open System: A system that exchanges matter and energy
with its surroundings is called an open system. .
Closed System: A system that can exchange only energy but
not matter with its surroundings is called a closed system.
Adiabatic Process: A process in which there is no exchange of
heat with the surroundings is called an adiabatic process.
Isothermal Process: A process which is carried out at
constant temperature is called an isothermal process.
Extensive Properties: The properties which depend on the
quantity of matter present in the system, e.g., mass,
volume, internal energy and enthalpy are called extensive properties.
Intensive Properties: The properties that do not depend on
the quantity of matter present in the system, e.g. temperature, pressure,
density and boiling point, are called intensive properties.
Enthalpy: It is a quantity associated with a
thermodynamic system and is expressed as the internal energy of system and
product of pressure and volume of the system.
H = E + PV
Enthalpy Of Formation: It is the heat
change when 1 mole of compound is formed from its elements.
Enthalpy Of Combustion: It is the heat
evolved when 1 mole of substance burns completely.
Enthalpy of Neutralisation: It is the heat
evolved when 1 equivalent of an acid is neutralised
completely with 1 equivalent of a base.
Hess's Law: This law states that heat change in a
chemical reaction is the same whether the reaction takes place in one stage
or several stages.
Thermochemistry: It is the branch of
chemistry that deals with enthalpy changes accompanying chemical changes.
Kirchhoff's Equation: The equation dealing
with the effect of temperature on the heat of reaction at constant pressure
or at constant volume.
DH2 - DH1 = DCp (T2
DE2 - DE1 = DCv (T2 - T1)