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Chemical Combinations - Theory Notes and Question Answers - Chemistry IX Theory Notes and Question Answers from Chapter No 02 "Chemical Combinations" for class 9th, IX, Ninth Class  2.1 LAWS OF CHEMICAL COMBINATIONS Q 1: What does the chemistry deal? ANS :      CHEMISTRY:               Chemistry deals with the matter and the changes occurring i it. Th chemical changes  are governed by some empirical laws known as laws of c mica! combinations. These laws are Law of conservation of mass. Law of constant composition or definite pro Law of multiple proportions. Law of reciprocal  Q.2: State the law of conservation of mass and  explain with examples. Ans:   LAW OF CONSERVATION OF MASS Introduction: Antoine Lavoisier discarded the worm out Of ideas about the changes that occur during a  chemical reaction. By making careful quantitative measurements, he es...

Chapter # 01 Chemistry - IX, Night, 9th  Theory & Question Answers INTRODUCTION TO CHEMISTRY 1.1 WHAT IS CHEMISTRY (DEFINITION AND ITS IMPORTANCE) Q.1: Define chemistry and describe its importance. Ans: CHEMISTRY: Chemistry is the branch of science that deals with the proper composition and structure of matter. OR Chemistry ¡s the branch of science that deals with the study of properties, composition and structure of matter along with chemical changes involved in it and principles governing these changes. IMPORTANCE OF CHEMISTRY: Ø   Chemistry enables us to design all sorts of materials like. Ø   Drugs to fight a disease. Ø   Pesticides to protect our health and crops. Ø   Fertilizers to grow our crops for abundant food.