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प्रश्न
Define a chemical change. Give two examples of the above changes.
उत्तर
A permanent change in which new substances are formed whose composition and properties are completely different from those of the original
substances.
Chemical change:
(i) Burning of wood.
(ii) Breathing.
संबंधित प्रश्न
Classify the following as chemical or physical change:
Boiling of water to form steam.
Changes in which only ______ properties of a substance change are called physical changes.
Dissolving salt in water is a reversible change.
Chemical changes are accompanied by changes in energy.
Make a list of different types of changes with example.
State three differences between evaporation and boiling
State whether the following is physical or chemical changes.
burning of sugar —
State whether the following is physical or chemical changes.
Slaking of lime —
True or false
Change of seasons is a non-periodic change.
Photosynthesis cannot take place at night.
What is a chemical change ? Give two examples of chemical changes.
Which of the following are physical changes and which are chemical changes ?
Freezing of water
Given reason:
Burning of paper is a chemical change.
Give four difference between physical and chemical changes.
Fill in the blank with the correct word of the statement given below:
Sublimation of iodine is an example of _________ change.
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 |
Physical Change: Boiling::Chemical Change: ______.
Assertion: The explosion of fire cracker is a physical change.
Reason: A physical change is a reversible change.
Give an example to justify the statement that physical changes can be reversible as well as irreversible.
