Study Material For Class IX Chemistry

About this eBook

CONTENTS S.NO.
Topics
Page No
1.
MATTER IN OUR SUROUNDINGS
1 - 15
2.
IS MATTE AROUND US PURE
16- 45
3.
ATOMS AND MOLECULES
46 - 71
4.
STRUCTURE OF ATOM
72 - 89
MATTER IN OUR SURROUNDINGS
INTRODUCTIONThere are a large number of things around us which we see and feel. For example, we can see a book in front of us. A book occupies some space. The space occupied by the book is called it volume. If we pick up the book, we can also feel its weight. So, we conclude that the book has some mass. We cannot see the air around us, yet if we fill a balloon with air and then weight it carefully, we will find that not only does air occupy space bounded by the balloon , but is also has mass. Things like a book and air are examples of matter. Other examples of matter are wood, cloth, paper, ice, steel, water, oil etc. Further, that matter offers resistance is borne out by the fact that we cannot displace an object from one place to another without applying some force. We have to apply force to pick up a stone from the ground. Thus, matter can be defined as follows Anything that occupies space, has mass and offer resistance is called matter. SUBSTANCE A substance is a kind of matter that cannot be separated into other kinds of matter by any physical process. For example, sugar dissolved in water can be separated from water by simply evaporating the water. Here sugar is a substance which cannot be broken into its components by any physical process. PHYSICAL NATURE OF MATTER a Matter is Made up of Particles i Everything around us is made up of many tiny pieces or particles.