The second chapter includes the detailed classification of pure substances and impure substances that is a mixture.   It also includes the detailed difference between pure substance and mixture on the basis of nature,  structure,  composition,  properties,  separation of constituents and energy changes.  More over this it includes types of solutions and different concentration terms involved in these solutions. Further, it has a detail difference between true solution,  colloidal solutions and suspensions. It also includes the different techniques for the separation of components of a heterogeneous mixture. Then at the end of this chapter, it includes physical and chemical changes occurring around us.

The third chapter is atoms and molecules which have different laws of chemical combinations,  Dalton's atomic theory, detailed description of elements,  atoms and molecules their chemical symbols, the concept of atomicity , atomic mass,  molecular mass and formula mass , writing chemical and molecular formula. Further is covers the mole concept, calculations of mole concept in different forms like mass,  particles and volumes in case of gaseous species.