Chemistry Notes of unit 5 9th class MCQs and Short Questions Gases diffuse very rapidly. Diffusion is mixing up of a gas throughout a space or other gases. Effusion is escaping of a gas molecule through a fine hole into an evacuated space. Gases exert pressure. The SI unit of pressure is Nm-2 which is … Read more
9th Class chemistry notes of unit 4 MCQs and Short Questions Atoms of different elements react to attain noble gas configuration, which is stable one. Chemical bonds may be formed by complete transfer of electrons (ionic); mutual sharing (covalent) or by donation from an atom(coordinate or dative covalent). Metals have the tendency to lose electrons … Read more
9th Class notes of chemistry chapter 3 MCQs and Short Questions In nineteenth century attempts were made to arrange elements in a systematic manner. Dobereiner arranged elements in a group of three called triads. Newlands arranged elements in groups of eight like musical notes. Mendeleev constructed Periodic Table containing periods and columns, by arranging elements … Read more
9th Class Chemistry Notes of Chapter 2 MCQs and Short Questions Cathode rays were discovered in last decade of nineteen century. The properties of cathode rays were determined and they led to the discovery of electron. Canal rays were discovered in 1886 by Goldstein . The properties of canal rays resulted in the discovery of … Read more
9th Class Chemistry Notes of Chapter 1 MCQs, Short Questions Chemistry is study of composition and properties of matter. It has different branches. Substances are classified into elements and compounds. Elements consist of only one type of atoms. Compounds are formed by chemical combination of atoms of the elements in a fixed ratio. Mixtures are … Read more
