A chemical change is a change in which one or more new substances are formed. These new substances have properties different from the original substances.
Burning of wood, rusting of iron, digestion of food and reaction of zinc with dilute sulphuric acid are examples of chemical changes. In these cases, the original substances do not simply change shape or state; they form new substances.
Signs of Chemical Change
- Change in colour
- Evolution of gas
- Change in temperature
- Formation of precipitate
- Change in smell or formation of new substance
Example
When iron reacts with copper sulphate solution, the blue solution becomes greenish and copper is deposited. This shows that a new substance has formed, so it is a chemical change.
Connection with Chemical Reaction
A chemical reaction is the scientific way of representing and explaining a chemical change. Every chemical reaction is a chemical change.
Chemical change wo change hai jisme ek ya zyada new substances bante hain. In new substances ki properties original substances se different hoti hain.
Wood ka burn hona, iron ka rust hona, food ka digestion aur zinc ka dilute sulphuric acid se react karna chemical changes hain.
Signs of Chemical Change
- Colour change
- Gas evolution
- Temperature change
- Precipitate formation
- New smell ya new substance formation
Connection with Chemical Reaction
Chemical reaction chemical change ko scientifically explain karne ka tareeka hai. Har chemical reaction ek chemical change hota hai.
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