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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
उत्तर
- Plant growth: Five types of hormones are found in plants, which cause plant growth through chemical processes.
- Rusting of iron: Iron forms undesirable substances when it comes in contact with moisture.
- Cooking of food: Vapors arise while cooking food which is a chemical change.
- Digestion of food: There are chemicals inside our body for digestion.
- Burning of candle: Oxygen is required for this so it is a chemical change.
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संबंधित प्रश्न
Write true or false for the statement.
Deforestation is a man-made change
Photosynthesis cannot take place at night.
What do you observe when :
lighted match stick is brought near the mouth of the test tube containing hydrogen gas.
State whether the following is physical or chemical changes.
shaping a piece of glass —
Write true or false
Burning of sugar is a temporary change.
Write true or false
Burning of paper and formation of curd are reversible changes.
Photosynthesis cannot take place at night.
What is a physical change ? Give two examples of physical changes.
Fill in the blank with the correct word of the statement given below:
Sublimation involves a __________ change.
Mention some of the different conditions needed for chemical changes to occur.
