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प्रश्न
What is a chemical change ? Give two examples of chemical changes.
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उत्तर
Chemical change: These changes occur when a substance combines with another to form a new substance. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions.
Examples:
- Rusting of iron
- Burning of paper
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Melting of butter in a pan
Explain the following giving an example.
Pure substance
Fill in the blank
Changes that occur in nature are called ______
Which of the following are chemical changes ?
- decaying of wood
- burning of wood
- sawing of wood
- hammering of nail into wood
Fill in the blank.
The reaction in which energy is evolved is called
Change is the law of nature which occurs in everyday life.
State when a substance [i.e. matter] undergoes a kind of change.
Select the chemical changes from the following list of changes
Vaporisation of water into water vapour.
Classify the following changes as physical and chemical changes
A rough piece of wood is sanded and polished resulting in change in texture, Rusting of a iron nail, Painting the grill, Bending a paper clip, Pounding silver into thin plate, Rolling the chappathi dough into thin wire, Occurrence of day and night, eruption of volcano, burning of matchstick, dosa from the batter, blinking of eyelids, occurrence of a thunderstorm, rotation of the earth, formation of eclipses.
| Sr. No. | Physical changes | Chemical changes |
| 1. | ||
| 2. |
Wood to sawdust:______:: Wood to Ash: Chemical change
Classify the following as physical or chemical properties
The composition of a sample of steel is 98% iron, 1.5% carbon and 0.5% other elements.
