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प्रश्न
Distinguish physical and chemical changes.
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उत्तर
1. Physical changes:
- No new substance is formed
- Reversible
- Change in physical properties like size, shape, state
- Melting of ice, tearing of paper freezing, evaporation vaporization
2. Chemical changes:
- New substance is formed
- Irreversible
- Change in properties of reactants and products
- Burning of paper, photosynthesis, digestion of food, rusting of iron
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संबंधित प्रश्न
Tick the most appropriate answer
2. Melting of ice is a
- reversible change
- irreversible change
- chemical change
- none of these
Match the columns.
| Column A | Column B |
| 1. a change which cannot be easily reversed | a. man-made change |
| 2 a change that repeats itself at regular intervals | b. chemical chang |
| 3. a change that is made by humans | c. physical change |
| 4. a change in which the original substance cannot be obtained | d. periodic change |
| 5. a change where no new substance is formed | e. irreversible change |
| f . slow change |
Two chemical substances X and Y combine together to form a product P which contains both X and Y X + Y P
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following statements concerning X, Y and P are correct ?
- P is a compound
- X and Y are compounds
- X and Y are elements
- P has a fixed composition
Classify the following as physical or chemical change :
Growth of a plant
Which of the following are physical changes and which are chemical changes ?
Freezing of water
Classify the following as a physical or a chemical change.
Manufacture of salt from sea water
Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Natural and man-made change.
Ammonium chloride is also a sublimable solid. Give a reason why the sublimation of ammonium chloride involves a physical and a chemical change.
You are given some candle wax. Can you make a candle doll from it? What kind of change is this?
Tearing of sheet of paper into pieces is ______ By the process of Heating of water, change.
