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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.
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
What do you observe when :
lighted match stick is brought near the mouth of the test tube containing hydrogen gas.
Write true or false
Burning of sugar is a temporary change.
Two chemical substances X and Y combine together to form a product P which contains both X and Y X + Y P
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following statements concerning X, Y and P are correct ?
- P is a compound
- X and Y are compounds
- X and Y are elements
- P has a fixed composition
Fill in the blank.
The process of a liquid changing into a solid is called ________
Change is the law of nature which occurs in everyday life.
State when a substance [i.e. matter] undergoes a kind of change.
Select the chemical changes from the following list of changes
The occurrence of lightning.
Select the chemical changes from the following list of changes
Butter turning rancid
Give the reason why the following is considered as chemical changes.
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Distinguish physical and chemical changes.
