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प्रश्न
Fill in the blank.
The reaction in which energy is evolved is called
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उत्तर
The reaction in which energy is evolved is called exothermic reaction.
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संबंधित प्रश्न
Tick the most appropriate answer.
4. Chemical changes involve
- change in shape.
- change in size.
- change in molecular composition.
- none of these
Fill in the blank.
Changes that occur in nature are called ........................
What role does energy play in initiating a chemical change ?
Fill in the blank
Heat is ________ by a gas during the process of condensation.
Classify the Following as a Physical Or a Chemical Change.
Curdling of Milk
Is a change of state of matter – a physical or a chemical change. Give reasons.
Give a reason why rusting of iron is a chemical change but, the magnetization of iron is a physical change.
Give the reason why the following is considered as chemical changes.
An iron nail kept open in the atmosphere rusts.
Match the following
| Sr. No. | A | B | C |
| 1. | Melting | Change of state from liquid to solid | Ticking of clock |
| 2. | Condensation | Change of state from liquid to gas | Formation of ice cube |
| 3. | Evaporation | Change of state from solid to liquid | Collecting flowers |
| 4. | Freezing | Change of state from gas to liquid | Ice cube to water |
| 5. | Periodic change | Occurs at irregular time intervals | Water to steam |
| 6. | Non-periodic change | Occurs at regular time intervals | Steam to water drops |
Wood to sawdust:______:: Wood to Ash: Chemical change
