Class 9 Science

This chapter explains laws of chemical combination, Dalton’s atomic theory, the ideas of atoms, molecules, ions, and how to write chemical formulae and calculate atomic, molecular and formula unit mass. These ideas form the basic language of chemistry for higher classes. 3.1 Laws of Chemical Combination By the end of the 18th century, scientists clearly […]

This chapter explores the difference between pure substances and mixtures, explains types of mixtures (homogeneous and heterogeneous), and describes solutions, suspensions, and colloids. You will learn about concentration calculations, the Tyndall effect, and the classification of matter into elements and compounds with their properties. Introduction When we buy items like milk, ghee, butter, salt, or