A chemical reaction is a process in which reactants change into products by rearrangement of atoms, ions or molecules. Old bonds break and new bonds form, so new substances are produced.
For example, when magnesium burns in oxygen, magnesium oxide is formed. This is a chemical reaction because a new substance with new properties is produced.
How to Identify a Chemical Reaction
- Change in state
- Change in colour
- Evolution of gas
- Change in temperature
- Formation of precipitate
Examples
Zinc reacts with dilute sulphuric acid to produce hydrogen gas. Iron reacts with copper sulphate solution and changes the blue solution to greenish. Lead nitrate reacts with potassium iodide to form a yellow precipitate of lead iodide.
Chemical Reaction and Chemical Equation
A chemical equation represents a chemical reaction using symbols and formulas. Reactants are written on the left side and products on the right side. A balanced equation follows the law of conservation of mass.
Chemical reaction wo process hai jisme reactants products me change hote hain. Isme atoms, ions ya molecules rearrange hote hain. Old bonds break hote hain aur new bonds form hote hain.
Example: magnesium oxygen me burn hokar magnesium oxide banata hai. Ye chemical reaction hai kyunki new substance banta hai.
How to Identify a Chemical Reaction
- Change in state
- Change in colour
- Evolution of gas
- Change in temperature
- Formation of precipitate
Chemical Reaction and Chemical Equation
Chemical equation kisi chemical reaction ko symbols aur formulas se represent karti hai. Reactants left side par aur products right side par likhe jate hain. Balanced equation law of conservation of mass follow karti hai.
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