Acids Bases and Salts
Acids Bases and Salts PDF Download PDF
Chemistry Class 8
Water
Water is a compound made of hydrogen and oxygen. It can be separated into H2 and O2 by electrolysis. Water PDF Download PDF
Oxygen, Air & Burning
Nitrogen: dilutes the effect of oxygen and controls the rate of combustion. Needed for proteins and important compounds like fertilizers, ammonia, and nitric acid. Used to keep food fresh because it does not allow the growth of oxygen by preventing oxidation. Oxygen: needed to sustain life, and for combustion Carbon dioxide: needed for photosynthesis, retains
Elements and Compounds
Atoms are the smallest unit of matter. Elements are made of the same type of atoms. They are represented by a symbol. Compounds have different kinds of atoms combined in fixed ratios. They are represented by a formula. Molecules are the smallest unit of elements or compounds which can exist independently. The number of atoms
Metals and Non-metals
Naturally occurring substances of metals present in the earth’s crust are called minerals. The method used in the extraction of minerals from their ores profitably is called metallurgy. Minerals that can be used to obtain the metal profitably are called ores. Metals and Non-metals PDF Download PDF
Carbon and Its Compounds
Allotropy is the phenomenon where an element exists in two or more forms with identical chemical properties but different physical properties…… Carbon and Its Compounds PDF Download PDF
Transformation of Substances
Boiling point: the temperature at which liquid changes to a vapor state under normal atmospheric pressure. Melting point: the temperature at which solid changes into liquid at normal atmospheric pressure. Impurities cause an increase in boiling point and a decrease in melting point. Transformation of Substances PDF Download PDF
Hydrogen
Pure hydrogen burns but it is a non-supporter of combustion. Burns in oxygen with a blue flame to form steam. It is used for Cutting and welding metals, As a fuel, Hydrogenation of vegetable oil, Manufacture of ammonia, methanol, HCl, Hydrogen balloon Hydrogen PDF Download PDF
Structure of Atom
Thomson plum pudding model: Rutherford model: Bohr model: Structure of Atom PDF Download PDF