Problems in Physical Chemistry by Narendra Awasthi

[Page 1] For More Material Join: @JEEAdvanced2024 [Page 2] For More Material Join: @JEEAdvanced2024 [Page 3] For More Material Join: @JEEAdvanced_2024 [Page 4] Laws of Chemical Combination Chemical reactions take place according to certain laws. These laws are called the Laws of Chemical Combination. “These are no longer useful in chemical calculations now but gives an idea of earlier methods of analysing and relating compounds by mass.” v Law of Conservation of Mass [Lavoisier (1774)] During any physical or chemical change, the sum of masses of all substances present in reactions vessel remain conserved. v Law of Constant Composition or Definite Proportions [Proust (1799)] In a given chemical compound, the elements are always combined in the same proportions by mass. v Law of Multiple Proportions [Dalton (1803)] Whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers. v Law of Reciprocal Proportions [Richter (1792)] When two elements combine separately with a fixed mass of a third elements then the ratio of their masses in which they do so is either same or some whole number multiple of the ratio in which they combine with each other. v Gay-Lussac’s Law of combining volumes According to Gay-Lussac’s law of combining volume, when gases react together, they always do so in volumes which bear a simple ratio to one another and to the volumes of the produc