how much mark u get in 10 Revision Notes on Thermodynamics Thermodynamics:- It is the branch of physics which deals with process involving heat, work and internal energy. Thermodynamics is concerned with macroscopic behavior rather than microscopic behavior of the system. Basic Terminology:- System Part of the universe under investigation. Open System A system which can exchange both energy and matter with its surroundings. Closed System A system which permits passage of energy but not mass, across its boundary. Isolated system A system which can neither exchange energy nor matter with its surrounding. Surroundings Part of the universe other than system, which can interact with it. Boundary Anything which separates system from surrounding. State variables The variables which are required to be defined in order to define state of any system i.e. pressure, volume, mass, temperature, surface area, etc. State Functions Property of system which depend only on the state of the system and not on the path. Example: Pressure, volume, temperature, internal energy, enthalpy, entropy etc. Intensive properties Properties of a system which do not depend on mass of the system i.e. Temperature, pressure, density, concentration , Extensive properties Properties of a system which depend on mass of the system i.e. Volume, energy, enthalpy, entropy etc. Process Path along which state of a system changes. Isothermal process Process which takes place at constant temperature Isobaric process Process which takes place at constant pressure Isochoric process Process which takes place at constant volume. Adiabatic process Process during which transfer of heat cannot take place between system and surrounding. Cyclic process Process in which system comes back to its initial state after undergoing series of changes. Reversible process Process during which the system always departs infinitesimally from the state of equilibrium i.e. its direction can be reversed at any moment. Kinetic Energy:- Energy possessed by the atoms or molecules by virtue of their motion is called kinetic energy. Internal Energy (ΔU):- Sum total of kinetic and potential energies of atoms/molecules constituting a system is called the internal energy of the system. (a) ΔU is taken as positive if the internal energy of the system increases. (b) ΔU is taken as negative if the internal energy of the system decreases. Heat:- Heat is the part of internal energy which is transferred from one body to another an account of the temperature difference. Work:- Work is said to be done when a force acting on a system displaces the body in its own direction. dW = Fdx = PdV W = P ( V f - V i ) (a) If the gas expands, work is said to be done by the system. In this case V f > V i , therefore, W will be positive. (b) If the gas is compressed, work is said to be done on the system. In this case V f V i , therefore, work done is negative. Thermodynamic variables or parameters:- The thermodynamic state of system can be determined by quantities like temperature (T), volume (V), pressure (P), internal energy (U) etc. These quantities are known as thermodynamic variables, or the parameters of the system. Equation of state:- A relation between the values of any of the three thermodynamic variables for the system, is called its equation of state.

how much mark u get in 10 

Revision Notes on Thermodynamics

• Thermodynamics:- It is the branch of physics which deals with process involving heat, work and internal energy. Thermodynamics is concerned with macroscopic behavior rather than microscopic behavior of the system.

• Basic Terminology:-

System	Part of the universe under investigation.
Open System	A system which can exchange both energy and matter with its surroundings.
Closed System	A system which permits passage of energy but not mass, across its boundary.
Isolated system	A system which can neither exchange energy nor matter with its surrounding.
Surroundings	Part of the universe other than system, which can interact with it.
Boundary	Anything which separates system from surrounding.
State variables	The variables which are required to be defined in order to define state of any system i.e. pressure, volume, mass, temperature, surface area, etc.
State Functions	Property of system which depend only on the state of the system and not on the path. Example: Pressure, volume, temperature, internal energy, enthalpy, entropy etc.
Intensive properties	Properties of a system which do not depend on mass of the system i.e. Temperature, pressure, density, concentration,
Extensive properties	Properties of a system which depend on mass of the system i.e. Volume, energy, enthalpy, entropy etc.
Process	Path along which state of a system changes.
Isothermal process	Process which takes place at constant temperature
Isobaric process	Process which takes place at constant pressure
Isochoric process	Process which takes place at constant volume.
Adiabatic process	Process during which transfer of heat cannot take place between system and surrounding.
Cyclic process	Process in which system comes back to its initial state after undergoing series of changes.
Reversible process	Process during which the system always departs infinitesimally from the state of equilibrium i.e. its direction can be reversed at any moment.

• Kinetic Energy:- Energy possessed  by the atoms or molecules by virtue of their motion  is called kinetic energy.

• Internal Energy (ΔU):- Sum total of kinetic and potential energies of atoms/molecules constituting a system is called the internal energy of the system.

(a) ΔU is taken as positive if the internal energy of the system increases.

(b) ΔU is taken as negative if the internal energy of the system decreases.

• Heat:- Heat is the part of internal energy which is transferred from one body to another an account of the temperature difference.
• Work:- Work is said to be done when a force acting on a system displaces the body in its own direction.

dW = Fdx = PdV

W = P(Vf -Vi)

(a) If the gas expands, work is said to be done by the system. In this case Vf > Vi, therefore, W will be positive.

(b) If the gas is compressed, work is said to be done on the system. In this case Vf   Vi, therefore, work done is negative.

• Thermodynamic variables or parameters:- The thermodynamic state of system can be determined by quantities like temperature (T), volume (V), pressure (P), internal energy (U) etc. These quantities are known as thermodynamic variables, or the parameters of the system.

• Equation of state:- A relation between the values of any of the three thermodynamic variables for the system, is called its equation of state.