Advertisements
Advertisements
प्रश्न
Define physical change. Give two examples for the above changes.
Advertisements
उत्तर
Physical change: A temporary change in which no new substance is formed, the composition of substance remains the same, though its state, shape and size may change.
Example of physical change:
- Change of water into its vapours.
- Heating of iron rod.
संबंधित प्रश्न
Classify the following as chemical or physical change:
Melting of butter in a pan
Explain the following giving an example.
Pure substance
Which of the following are chemical changes?
- Growth of a plant
- Rusting of iron
- Mixing of iron fillings and sand
- Cooking of food
- Digestion of food
- Freezing of water
- Burning of candle
Tick the most appropriate answer.
5. Photosynthesis requires
- heat energy.
- wind energy
- sunlight.
- sound energy
Write true or false for the statement
Decomposition of leaves is a fast change.
Ripening of fruits is a desirable change.
Melting of solid (wax) is a physical change.
Write short answer.
Give an example of desirable change which can also be undesirable
How do you say that the process of digestion is a chemical change ?
State whether the following is physical or chemical changes.
(energy produced) dissolving sugar in water —
Tick (√) the correct alternative from the choice given for the following statement
A pop sound is heard when a lighted match stick is brought near the mouth of a jar. This indicates the release of gas.
Write true or false
Decomposition of leaves is a fast change.
Make a list of different types of changes with example.
Give three reasons why melting of wax, is considered a physical change while burning of a candle, a chemical change.
Give four reasons why the burning of a magnesium ribbon in the air is considered a chemical change.
Match the examples of changes in List I with the correct type of change in List II.
| List I | List II |
| 1. Burning of paper | A: Physical change |
| 2. The ringing of an electric bell | B: Chemical change |
| 3. Curdling of milk | |
| 4. Electric light is switched on | |
| 5. Melting of butter |
You are given some candle wax. Can you make a candle doll from it? What kind of change is this?
When solute is dissolved in a solvent it forms a solution.
Mention some of the different conditions needed for chemical changes to occur.
