Class 10 GENERAL INTRODUCTION

Topics to be covered

`=>` General introduction

Introduction

In our daily life we experience a lot of changes taking place. Some might be physical change and some might be chemical change. For eg:

๐Ÿ ๐–๐ก๐ž๐ง ๐ฆ๐ข๐ฅ๐ค ๐ข๐ฌ ๐ฅ๐ž๐Ÿ๐ญ ๐š๐ญ ๐ซ๐จ๐จ๐ฆ ๐ญ๐ž๐ฆ๐ฉ๐ž๐ซ๐š๐ญ๐ฎ๐ซ๐ž ๐๐ฎ๐ซ๐ข๐ง๐  ๐ฌ๐ฎ๐ฆ๐ฆ๐ž๐ซ๐ฌ.
๐Ÿ ๐–๐ก๐ž๐ง ๐š๐ง ๐ข๐ซ๐จ๐ง ๐ญ๐š๐ฐ๐š/๐ฉ๐š๐ง/๐ง๐š๐ข๐ฅ ๐ข๐ฌ ๐ฅ๐ž๐Ÿ๐ญ ๐ž๐ฑ๐ฉ๐จ๐ฌ๐ž๐ ๐ญ๐จ ๐ก๐ฎ๐ฆ๐ข๐ ๐š๐ญ๐ฆ๐จ๐ฌ๐ฉ๐ก๐ž๐ซ๐ž.
๐Ÿ‘ ๐–๐ก๐ž๐ง ๐ ๐ซ๐š๐ฉ๐ž๐ฌ ๐ ๐ž๐ญ ๐Ÿ๐ž๐ซ๐ฆ๐ž๐ง๐ญ๐ž๐.
๐Ÿ’ ๐–๐ก๐ž๐ง ๐Ÿ๐จ๐จ๐ ๐ข๐ฌ ๐œ๐จ๐จ๐ค๐ž๐.
๐Ÿ“ ๐–๐ก๐ž๐ง ๐Ÿ๐จ๐จ๐ ๐ ๐ž๐ญ๐ฌ ๐๐ข๐ ๐ž๐ฌ๐ญ๐ž๐ ๐ข๐ง ๐จ๐ฎ๐ซ ๐›๐จ๐๐ฒ
๐Ÿ” ๐–๐ก๐ž๐ง ๐ฐ๐ž ๐ซ๐ž๐ฌ๐ฉ๐ข๐ซ๐ž.

โ˜…

`color{red}(underset("(As ribbon)")("Magnesium") + underset("From air")(" Oxygen") overset(" heat")โ†’ underset("white power")( " Magnesium oxide"))`

`color{green}("๐Ž๐๐’๐„๐‘๐•๐€๐“๐ˆ๐Ž๐:")` Magnesium ribbon burns with a dazzling white flame and changes into a white powder. This powder is magnesium oxide. It is formed due to the reaction between magnesium and oxygen present in the air.

(Here magnesium ribbon is cleaned by sand paper to remove the protective layer of basic magnesium carbonate from the surface of magnesium ribbon so that it can readily combine with the oxygen of air).

Hence, this activity shows that burning of magnesium in air is an example of chemical reaction.
โ˜…

`color{green}("๐Ž๐๐’๐„๐‘๐•๐€๐“๐ˆ๐Ž๐:")` The reaction between lead nitrate and potassium iodide leads to the formation of yellow precipitate of lead iodide.
( `color{red}("๐๐‘๐„๐‚๐ˆ๐๐ˆ๐“๐€๐“๐„ :")` It is a solid product which seperates out from solution during a chemical reaction.)

โ˜…


`color{green}("๐Ž๐๐’๐„๐‘๐•๐€๐“๐ˆ๐Ž๐ :")` The chemical reaction between zinc and sulphuric acid is characterized by evolution of hydrogen gas.

From the above three activities, we can say that any of the following observations helps us to determine whether a chemical reaction has taken place โ€“

๐Ÿ ๐œ๐ก๐š๐ง๐ ๐ž ๐ข๐ง ๐ฌ๐ญ๐š๐ญ๐ž
๐Ÿ ๐œ๐ก๐š๐ง๐ ๐ž ๐ข๐ง ๐œ๐จ๐ฅ๐จ๐ฎ๐ซ
๐Ÿ‘ ๐ž๐ฏ๐จ๐ฅ๐ฎ๐ญ๐ข๐จ๐ง ๐จ๐Ÿ ๐š ๐ ๐š๐ฌ
๐Ÿ’ ๐œ๐ก๐š๐ง๐ ๐ž ๐ข๐ง ๐ญ๐ž๐ฆ๐ฉ๐ž๐ซ๐š๐ญ๐ฎ๐ซ๐ž.

 
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