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प्रश्न
Give the reason why the following is considered as chemical changes.
Copper carbonate on heat gives copper oxide and carbon dioxide.
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उत्तर
Copper carbonate [CuCO3] green colour on heating gives copper oxide [Black colour CuO] and CO2.
Hence composition is changed new substances CuO [Black] and CO2 with new properties are produced and it is irreversible reaction hence it is a chemical change.
\[\ce{\underset{\text{Green}}{CuCO3} ->[\Delta] \underset{\text{Black}}{CuO} + CO2}\]
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संबंधित प्रश्न
Which of the following are chemical changes?
- Growth of a plant
- Rusting of iron
- Mixing of iron fillings and sand
- Cooking of food
- Digestion of food
- Freezing of water
- Burning of candle
Melting of solid (wax) is a physical change.
Write short answer.
Give two examples of periodic changes
Fill in the blank.
When a candle burns, wax melts. Melting of wax is a ________ change.
State whether the following is physical or chemical changes.
growing of a piglet into a pig —
State whether the following is physical or chemical changes.
cutting wood into small pieces —
State one instance where water undergoes a physical change and one in which it undergoes a chemical change.
Match the examples of changes in List I with the correct.
| List I | List II |
| 1. Expansion of a steel rod on heating | A: Physical change |
| 2. Rotting of eggs | B: Chemical change |
| 3. Milk turning sour | |
| 4. Tarnishing of copper | |
| 5. Separation of naphthalene from a mixture of naphthalene and sodium chloride. |
Select the chemical changes from the following list of changes
Breaking of glass
The change of state of a substance from solid to liquid and liquid to gas is ______.
