The part of the universe we choose to study is called a system. The parts of the universe with which the system interacts are called the surroundings. Three systems: open system, closed system and isolated system.
Internal Energy (E) is the total amount of energy (potential, kinetic, chemical energy,…) contained in a system. The components of internal energy are:
Translational kinetic energy
Energy is the capacity to do work.
Work is done when a force acts through a distance. A system contains only internal energy.
– A system does not contain heat (q) or work (w).
– Energy transfer can occur as heat or work during a change in the system.
Chemical reactions may also do work.
• Gas formed pushes against the atmosphere.
• Volume changes.
• Pressure-volume work is done.
The most common type of work associated with chemical reactions is pressure-volume work. This is work involved in the expansion or compression of gases.