Thermodynamics system

Thermodynamic system 

System and surrounding:

• A system is a matter or region on which analysis is done.
• Everything external to the system is called surrounding.

System + Surrounding = "Universe"

Boundary:

• It separates system and surroundings.
• It can be fixed or movable.
• Fixed boundary ex: cylinder containing gas
• Movable boundary ex : cylinder with piston

Types of system:

Closed system:

A system is said to be a closed system when there is no mass transfer and only heat/energy transfer takes place.

Example: A gas in a closed cylinder without valves . 

Open system:

A system is said to be a open system when there both heat/energy and mass transfer takes place in a system.

Example: Diesel engine 

Isolated system:

A system is said to be an isolated system when there both heat/energy and mass transfer takes place.

Example: Hot water in a fully insulated closed container.