What is Thermodynamics?

The science of energy, that concerned with the ways in which energy is stored within a body. 

Energy transformations – mostly involve heat and work movements. The Fundamental law is the conservation of energy principle: energy cannot be created or destroyed, but can only be transformed from one form to another.

System, surroundings and boundary

System:- A quantity of matter or a region in space chosen for study. 

Surroundings:- The mass or region outside the system 

Boundary:- The real or imaginary surface that separates the system from its surroundings. 

Type of system (isolated system)

Isolated system – neither mass nor energy can cross the selected boundary

 

Example (approximate): coffee in a closed, well-insulated thermos bottle 

Type of system (Closed system) 

Closed system – only energy can cross the selected boundary 

Examples: a tightly capped cup of coffee 

Type of system (Open system) 

Open system – both mass and energy can cross the selected boundary

 

Example: an open cup of coffee 

Properties of a system 

Properties of a system is a measurable characteristic of a system that is in equilibrium.

 Properties may be intensive or extensive.

 

Intensive – Are independent of the amount of mass

 

e.g: Temperature, Pressure, and Density, 

 

Extensive – varies directly with the mass e.g: mass, volume, energy, enthalpy 

Specific properties – 

The ratio of any extensive property of a system to that of the mass of the system is called an average specific value of that property (also known as intensives property)