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प्रश्न
Name a chemical change which takes place in presence of:
उत्तर
Heat:
- Burning of paper.
- Cooking of food need heat.
Light :
- Formation of food by plants i.e. photosynthesis need light.
- Hydrogen and chlorine react in presence of light
Electricity:
- Water breaks into hydrogen and oxygen on passing electricity.
- Sodium chloride solution breaks up into its components sodium and Chlorine on passing electric current through sodium chloride solution.
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Cutting of trees
Solve this crossword by using the clues that follow.
Across
1. Energy in the form of sunlight is absorbed by the green plants in this process.
4. The reddish-brown substance formed over iron in the presence of oxygen and moisture.
5. This change is permanent and irreversible.
6. The process in which a solid directly changes into gaseous state.
Down
1. It is the change that takes place in case of swinging pendulum of a clock.
2. Occurrence of this is a non-periodic change as well as a natural change.
3. It is a physical change
State the Differences Between a Physical Change and a Chemical Change.
What is a chemical change ? Give two examples of chemical changes.
Ammonium chloride is also a sublimable solid. Give a reason why the sublimation of ammonium chloride involves a physical and a chemical change.
Fill in the blank with the appropriate word of the statement given below:
If a change is permanent and irreversible it is considered a _________ change.
Fill in the blank with the correct word of the statement given below:
Sublimation involves a __________ change.
Name the following:
The term involved in the change of state from – ‘water to ice’ – which is a physical change.
Name the following:
The type of change physical or chemical involved – ‘when a substance undergoes a change in state, colour or size’.
Select the correct answer from the choice given below to complete the sentence
The energy required for completion of a physical change is ______________ when the change is reversed.
