Selective notes for class 9th Introduction to gases, liquids and solids. Various Methods of Separation Distillation and Fractional distillation Differences between elements, compounds, and mixtures. Pure Substances What is the overall charge of an atom if there are 3 protons, 3 electrons, and 3 neutrons? What is the difference between molecular mass and formula mass? What are the characteristics of pure substances in points? How many atoms are there in 1 gram of carbon? How many oxygen atoms are there in 90g of H2O molecule? What is the number of moles of O-atom in 126 AMU of HNO3? Chemical Bond Atomic Structure Atomic Models Mole Concept What is valency ? How to calculate it? Share this:TwitterLinkedInFacebookEmailWhatsAppSkypePrintquoraRedditTumblrPinterestPocketTelegramLike this:Like Loading...