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प्रश्न
State the observations seen, when milk in a dish is kept aside for a few hours or more. Is the change which occurs – a physical change or a chemical change. Give reasons.
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उत्तर
On keeping aside – the milk in a dish for a few hours or more. The change observed – will be that the milk has changed into curd. The change is permanent and cannot be reversed. New substance curd is formed. It is a chemical change.
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Rusting of almirah
What role does energy play in initiating a chemical change ?
State whether the following is physical or chemical changes.
Slaking of lime —
Write true or false
Burning of sugar is a temporary change.
Differentiate between a physical change and a chemical change with reference to – Nature of change is temporary and reversible or permanent and irreversible.
Differentiate between a physical change and a chemical change with reference to – Energy change taking place during the respective change.
Select the chemical changes from the following list of changes
Preparation of carbon dioxide from calcium carbonate & dilute hydrochloric acid.
Select the correct answer from the choice given below to complete the sentence
A change in which a substance retains its identity is a
______ 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 |
Filling up a balloon with hot air is a _______ change.
