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प्रश्न
Given reason:
Freezing of water to ice and evaporation of water are physical changes.
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उत्तर
Freezing of water to ice and evaporation of water are physical change because water can be brought back to its original (liquid) form by
- We can heat the ice to bring it back to water.
- We can cool down the vapours to bring it back to water.
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संबंधित प्रश्न
Try segregating the things around you as pure substances or mixtures.
Write short answer.
Sublimation is classified as a physical change. Why ?
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 various conditions that favour the process of evaporation.
Classify the following as physical or chemical change :
Formation of curd from milk
Separate the following into physical and chemical changes :
Sublimation of a solid, Decomposition of water into hydrogen and oxygen by passing electric current, Formation of clouds, Making a fruit salad from raw fruits, Dissolving carbon dioxide in water
Which of the following are physical changes and which are chemical changes?
Burning of candle wax, Melting of candle wax, Mixing of iron filings and sand, Burning of wood, Breaking a piece of chalk, Burning a piece of paper, Cutting a piece of paper.
What is a physical change ? Give two examples of physical changes.
Which of the following are physical changes and which are chemical changes ?
Give a reason why – Addition of zinc nitrate to water is a physical change but, the addition of zinc to dilute nitric acid is a chemical change.
