Matter in Our Surroundings NCERT CLASS 9TH NOTES

 Matter in Our Surroundings NCERT CLASS 9TH NOTES

Introduction

• Chemistry is a branch of science which deals with the study of the composition of matter and the chemical changes involved in it. In other words, chemistry is the science of matter and its transformation. Like all other branches of science, chemistry has its own technical terms. In chemistry, all chemical reactions are expressed in terms of chemical equations which involve symbols and formulae. All chemical substances are expressed in symbols and formulae which form the language of chemistry. For example, in the language of chemistry; sodium is expressed as ‘Na’, potassium as ‘K’, water as ‘H2O’, calcium carbonate as ‘CaCO3 ’ and so on. When sodium chloride is heated with conc. sulphuric acid, we get sodium sulphate and hydrogen chloride.
• Since early times human beings have been trying to understand their nature. Early Indian philosopher classified matter into five basic elements. the“Panch Tatva”– air, earth, fire, sky and water. According to them, living as well as non living things are made up of these elements.
• Now a days, scientists evolved to types of classification of matter – physical properties and chemical nature.
• In this Chapter we will deals with physical properties of matter .

Matter 

• It is anything that takes up space and has mass, doesn’t have to be visible - even air is matter.
• There are three familiar states of matter—solid, liquid, and gas.

Physical Nature Of matter 

• For a long time were two views about physical nature of matter

1. Continuous nature (like a block of wood )
2. Particulate nature (like sand)

\But actually mater is made up of discreate particles.

Conclude that: 

•  Matter is made up of Particles, which means matter is particulate in Nature
•  The size of the particles of Matter is very small, they cannot be seen by naked eyes

Characteristics of Particles of Matter

1. matter is made up of particles 

Particles of Matter have space between them: When we dissolve particles of salt in water, the salt get disappear in water, this happens because particles of salt take up space between two particles of water and even there is No Rise in water level, this proves that particles of water have space between them