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प्रश्न
Define a chemical change. Give two examples of the above changes.
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उत्तर
A permanent change in which new substances are formed whose composition and properties are completely different from those of the original
substances.
Chemical change:
(i) Burning of wood.
(ii) Breathing.
संबंधित प्रश्न
When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.
Write true or false for the statement.
Deforestation is a man-made change
Ripening of fruits is a desirable change.
Classify the following changes as physical or chemical:-boiling
Fill in the blank.
Growing of a seedling into a plant is _______ change.
Write true or false
A natural change can also be a desirable change.
Classify the following as physical or chemical changes :
- Cooking of food
- Boiling of water
- Cutting of trees
- D0issolving salt in water
- Digestion of food
- Melting of ice
Classify the following as physical or chemical change :
Growth of a plant
Separate the following into physical and chemical changes :
Sublimation of a solid, Decomposition of water into hydrogen and oxygen by passing electric current, Formation of clouds, Making a fruit salad from raw fruits, Dissolving carbon dioxide in water
Which of the following are physical changes and which are chemical changes?
Burning of candle wax, Melting of candle wax, Mixing of iron filings and sand, Burning of wood, Breaking a piece of chalk, Burning a piece of paper, Cutting a piece of paper.
Change is the law of nature and occurs in our everyday life, at all times and in all places. Differentiate between the following change with a suitable example.
Desirable and undesirable change.
Name the following:
The type of change physical or chemical involved – ‘when a substance undergoes a change in state, colour or size’.
Select the chemical changes from the following list of changes
The carbon cycle.
Select the chemical changes from the following list of changes
The crystallisation of salt from its solution.
What is the difference between dissolution of sugar and burning of sugar ?
Tearing of sheet of paper into pieces is ______ By the process of Heating of water, change.
Gas exists in three states as solid, liquid, and gas.
Adding sugar to milk is a physical change.
Mention some of the different conditions needed for chemical changes to occur.
