Dalton's Atomic Theory John Dalton in 1808 put forward theory known as Dalton's atomic theory The main points of this theory are: (1) Matter is made up of extremely small indivisible particles called atoms. (2) Atoms of the same element are identical in all respect i.e. shape, size and mass. (3) Atoms of different elements have different masses, sizes and also … [Read more...] about Dalton’s Atomic Theory
Class 11
Laws of Chemical Combination
Law of Conservation of Mass This Law was studied by French chemist Antoine lavoisier in 1789 This law states that In all physical and chemical changes, the total mass of the reactants is equal to that of the products. Or Mass can neither be created nor destroyed. This law is also called as the law of indestructibility of matter. The mass and energy are … [Read more...] about Laws of Chemical Combination
Significant Figures
Accuracy of Measurement The accuracy of any measurements depends upon the (a) accuracy of the measuring device used (b) the skill of its operator. If the average value of different measurements is close to the correct value ,the measurement is said to be accurate. If the values of different measurements are close to each other and hence close to the average value, … [Read more...] about Significant Figures
Physical Quantities
Physical Properties Physical Properties are those which can be measured or observed without changing the identity or composition of the substance. For example : Mass, volume, melting point, boiling point. Chemical properties Chemical properties are those in which a chemical change in the substance occurs. The measurement of any physical quantity consists of two … [Read more...] about Physical Quantities
Classification of Matter
Matter Matter is defined as anything that occupies space and possesses mass. Classification of Matter (1) Physical classification (a) Solid (b) Liquid (c) Gases Solid Liquid Gases (1) They have fixed shape and volume They do not have fixed shape but have fixed volume They do not have fixed shape and volume (2) They cannot be compressed They … [Read more...] about Classification of Matter