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प्रश्न
Name the following:
The final product of the physical change involved during the ‘melting of a piece of wax’.
उत्तर
Wax [CxHy]
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संबंधित प्रश्न
What are reversible and irreversible changes ? Give one example for each.
State whether the following is physical or chemical changes.
water cycle in nature —
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
Give the main differences between physical changes and chemical changes.
State what is meant by the term – interconversion of matter. Is interconversion of matter a physical change or a chemical change.
Explain the term – ‘sublimation’. Is sublimation of naphthalene – a physical or a chemical change. Give reasons.
Photosynthesis is a natural process by which green plants manufacture food in the presence of sunlight.
State the conclusions which can be drawn, to represent photosynthesis as a physical or a chemical change.
Select the chemical changes from the following list of changes
Drying of a fruit
Two drops of dilute sulphuric acid were added to 1 g of copper sulphate powder and then a small amount of hot water was added to dissolve it (step I). On cooling, beautiful blue coloured crystals got separated (step II). Step I and Step II are:
What kind of change is shown by tearing off paper?
