Overview

System: This is a portion of the universe (e.g. a substance or a group of substances) set apart for study.

Closed system - A system with constant mass

Open system - A system with variable mass (mass is transferred across the boundaries of the system).

Thermodynamic properties: Any measurable characteristic of a system is called its property. eg temperature, pressure, mass, area volume surface tension etc. Intensive property is independent of mass. Extensive property depends on the mass of the system. State properties depend upon the thermodynamic state of the system and are independent of the path the system takes to reach that state. Some state properties are: pressure P, temperature T, specific volume v, internal energy U, enthalpy H , entropy S , Gibbs free energy G, Helmholz free energy A, heat capacities at constant pressure Cp and at constant volume C _v

MASS BALANCE:

Application of the accounting principle to mass of a system over an accounting period yields the mass balance equation:

M _E - M _B = ?M _I - ?M _O + ?M _P - ?M _C

ENERGY BALANCE First Law of Thermodynamics or principle of conservation of energy: Application of accounting principle to energy of a system over a chosen accounting period yields:

( U + PE + KE) _E - ( U + PE + KE) _B = ?