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प्रश्न
What do you observe when :
lighted match stick is brought near the mouth of the test tube containing hydrogen gas.
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उत्तर
We observe that hydrogen bums at the mouth of test tube with blue flame and pop sound is heard. It is chemical change.
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Melting of butter in a pan
Tick the most appropriate answer.
3. Physical changes are
- permanent.
- periodic,
- temporary
- irreversible.
Photosynthesis cannot take place at night.
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 whether the following is physical or chemical change.
Digestion of food —
Fill in the blank
Heat is ________ by a gas during the process of condensation.
Fill in the blank.
The process of a liquid changing into a solid is called ________
Fill in the blank with the correct word of the statement given below:
Sublimation of iodine is an example of _________ change.
______ is the Universal Solvent.
Match the items of Column I with the items of Column II.
| Column I | Column II | ||
| (a) | Large crystals | (i) | Turns lime water into milky |
| (b) | Depositing a layer of zinc on iron | (ii) | Physical change |
| (c) | Souring of milk | (iii) | Rust |
| (d) | Carbon dioxide | (iv) | Sugar candy (Mishri) |
| (e) | Iron oxide | (v) | Chemical change |
| (f) | Dissolving common salt in water | (vi) | Galvanisation |
