Department of Chemistry
Subject: Chemistry Subject Code: 18BSCH03
Module 1
Electrochemistry, Corrosion and Thermodynamics (12 hours)
Thermodynamic functions: Energy, entropy and free energy. Estimations of entropy and
free energies. Use of free energy considerations in metallurgy through Ellingham
diagrams.
Electrochemistry: Electrode potentials: Origin of electrode potential using Nernst
electrolytic pressure theory, Introduction to single electrode potential, Derivation of
Nernst equation, Electrochemical cell: Construction and working of Daniel cell using Zn
and Cu electrodes, electrochemical series, types of electrodes (Hydrogen, Calomel
electrode, glass electrode). Numerical problems based on determination of EMF.
Corrosion- causes- factors- electrochemical theory of corrosion, types-chemical,
electrochemical corrosion (galvanic, differential aeration), corrosion control - material
selection and design aspects - electrochemical protection – sacrificial anode method and
impressed current cathodic method.
, Thermodynamics
Basic Definitions
Thermodynamics is the science that seeks to predict the amount of energy needed to bring
about a change of state of a system from one equilibrium state to another.
Thermodynamics is the study of energy interactions between systems and the effect of
these interactions on the system properties or study of energy, energy transformations and
its relation to matter. Energy transfer between systems takes place in the form of heat
and/or work. Thermodynamics deals with systems in equilibrium.
Thermodynamics Terminology
We are interested in chemical reactions and the energy changes accompanying them. For
this we need to know certain thermodynamic terms. These are discussed below.
System
A system in thermodynamics refers to that part of universe in which observations are
made and remaining universe constitutes the surroundings or the part of the universe under
observation is called system.
Surroundings
In thermodynamics, the universe can be divided into two parts. One part is the system, the
other part is the rest of the universe called the surroundings.
Figure 1: System and the Surrounding
,For example: If we are studying the reaction between two substances A and B kept in
beaker, the beaker containing the reaction mixture is the system and the room temperature
where the beaker is kept is the surroundings. Note that the system may be defined by
physical boundaries, like beaker or test tube,
Types of System
System can be classified as
Open System
A system in which both flow of mass and heat is possible or in an open system, there is
exchange of energy and matter between the system and surroundings (Figure 2a). The
presence of reactants in an open beaker is an example of an open system. Here the
boundary is an imaginary surface enclosing the beaker and the reactants.
Closed System
A system in which flow of heat is possible but flow of mass is not possible or in a closed
system, there is no exchange of matter, but exchange of energy is not possible between
system and the surroundings (Figure 2b). The presence of reactants in a closed vessel
made of conducting material e.g., copper or steel is an example of a closed system.
Isolated System
In an isolated system, there is no exchange of energy or matter between the system and the
surroundings or A system in which neither heat nor mass can flow in or out (Figure 2c).
The presence of reactants in a thermos flask or any other closed insulated vessel is an
example of an isolated system.
, The State of the System
The system must be described in order to make any useful calculations by specifying
quantitatively each of the properties such as its pressure (p), volume (V), and temperature
(T) as well as the composition of the system. The state variables (P, V, T, n) describes the
condition of a system. By changing any one or more of these variables the state of the
system undergoes changes.
Properties of the System
All the properties of a system can be categorized into one of the following two types:
Extensive Properties
The properties of a system which depends on the mass or the total number of particles in
the system are categorized as extensive properties. e. g. Total Energy, volume.
Intensive Properties
The properties of a system which depends on concentration and does not depend on the
mass or the total number of particles in the system are categorized as Intensive properties.
eg. Pressure, Density, Refractive Index.
State and Path Functions
The thermodynamic functions which depend only on the initial and final states of the
system and not on the path followed are called state functions eg. Internal energy,
Enthalpy and the functions which depend on the path followed while changing from one
state to the other are called path functions. e.g. work heat.
Internal Energy
It is the sum total of the components of energy of the system due to the internal factors. It
is denoted by U (sometimes by E). Since the system under observation is an ideal gas thus
the internal energy of the system is dependent only on the kinetic energy of the gas and
therefore is only a function of temperature. U∝T. Since internal energy depends only on
temperature thus, it is a state function.
Subject: Chemistry Subject Code: 18BSCH03
Module 1
Electrochemistry, Corrosion and Thermodynamics (12 hours)
Thermodynamic functions: Energy, entropy and free energy. Estimations of entropy and
free energies. Use of free energy considerations in metallurgy through Ellingham
diagrams.
Electrochemistry: Electrode potentials: Origin of electrode potential using Nernst
electrolytic pressure theory, Introduction to single electrode potential, Derivation of
Nernst equation, Electrochemical cell: Construction and working of Daniel cell using Zn
and Cu electrodes, electrochemical series, types of electrodes (Hydrogen, Calomel
electrode, glass electrode). Numerical problems based on determination of EMF.
Corrosion- causes- factors- electrochemical theory of corrosion, types-chemical,
electrochemical corrosion (galvanic, differential aeration), corrosion control - material
selection and design aspects - electrochemical protection – sacrificial anode method and
impressed current cathodic method.
, Thermodynamics
Basic Definitions
Thermodynamics is the science that seeks to predict the amount of energy needed to bring
about a change of state of a system from one equilibrium state to another.
Thermodynamics is the study of energy interactions between systems and the effect of
these interactions on the system properties or study of energy, energy transformations and
its relation to matter. Energy transfer between systems takes place in the form of heat
and/or work. Thermodynamics deals with systems in equilibrium.
Thermodynamics Terminology
We are interested in chemical reactions and the energy changes accompanying them. For
this we need to know certain thermodynamic terms. These are discussed below.
System
A system in thermodynamics refers to that part of universe in which observations are
made and remaining universe constitutes the surroundings or the part of the universe under
observation is called system.
Surroundings
In thermodynamics, the universe can be divided into two parts. One part is the system, the
other part is the rest of the universe called the surroundings.
Figure 1: System and the Surrounding
,For example: If we are studying the reaction between two substances A and B kept in
beaker, the beaker containing the reaction mixture is the system and the room temperature
where the beaker is kept is the surroundings. Note that the system may be defined by
physical boundaries, like beaker or test tube,
Types of System
System can be classified as
Open System
A system in which both flow of mass and heat is possible or in an open system, there is
exchange of energy and matter between the system and surroundings (Figure 2a). The
presence of reactants in an open beaker is an example of an open system. Here the
boundary is an imaginary surface enclosing the beaker and the reactants.
Closed System
A system in which flow of heat is possible but flow of mass is not possible or in a closed
system, there is no exchange of matter, but exchange of energy is not possible between
system and the surroundings (Figure 2b). The presence of reactants in a closed vessel
made of conducting material e.g., copper or steel is an example of a closed system.
Isolated System
In an isolated system, there is no exchange of energy or matter between the system and the
surroundings or A system in which neither heat nor mass can flow in or out (Figure 2c).
The presence of reactants in a thermos flask or any other closed insulated vessel is an
example of an isolated system.
, The State of the System
The system must be described in order to make any useful calculations by specifying
quantitatively each of the properties such as its pressure (p), volume (V), and temperature
(T) as well as the composition of the system. The state variables (P, V, T, n) describes the
condition of a system. By changing any one or more of these variables the state of the
system undergoes changes.
Properties of the System
All the properties of a system can be categorized into one of the following two types:
Extensive Properties
The properties of a system which depends on the mass or the total number of particles in
the system are categorized as extensive properties. e. g. Total Energy, volume.
Intensive Properties
The properties of a system which depends on concentration and does not depend on the
mass or the total number of particles in the system are categorized as Intensive properties.
eg. Pressure, Density, Refractive Index.
State and Path Functions
The thermodynamic functions which depend only on the initial and final states of the
system and not on the path followed are called state functions eg. Internal energy,
Enthalpy and the functions which depend on the path followed while changing from one
state to the other are called path functions. e.g. work heat.
Internal Energy
It is the sum total of the components of energy of the system due to the internal factors. It
is denoted by U (sometimes by E). Since the system under observation is an ideal gas thus
the internal energy of the system is dependent only on the kinetic energy of the gas and
therefore is only a function of temperature. U∝T. Since internal energy depends only on
temperature thus, it is a state function.
