This document discusses fundamentals of chemical engineering related to single-phase systems and ideal gases. It includes: 1) Descriptions of liquid and solid densities, and how they are relatively independent of temperature and pressure changes. 2) Derivation of the ideal gas equation of state from kinetic theory, and examples of using the equation to calculate properties like volume and molar flow rates. 3) Introduction of the compressibility factor and using generalized compressibility charts to estimate non-ideal gas behavior based on reduced temperature and pressure.