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प्रश्न
Give the reason why the following is considered as chemical changes.
A bright light is seen evolved when a strip of magnesium is heated.
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उत्तर
Magnesium is heated producing a bright light to form MgO in the air is a chemical change as the composition changes (MgO white powder) is formed, is irreversible. We cannot get magnesium back from MgO.
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संबंधित प्रश्न
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
Fill in the blank.
When a candle burns, wax melts. Melting of wax is a ________ change.
Tick (√) the correct alternative from the choice given for the following statement
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What are man-made changes ?
Classify the following as a physical or a chemical change.
Burning of paper
Differentiate between a physical change and a chemical change with reference to – Energy change taking place during the respective change.
Explain the term – ‘sublimation’. Is sublimation of naphthalene – a physical or a chemical change. Give reasons.
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.
Stretching gold coin into a ring is a ______ change.
Which of the following is a physical change?
