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प्रश्न
Explain the following giving an example.
Pure substance
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उत्तर
- A pure substance is defined as one that contains only one type of atom or molecule.
- A pure substance has the same colour, taste and texture at any given temperature and pressure and a fixed melting and boiling point under continuous pressure.
- Examples include hydrogen gas, salt chloride, and water.
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संबंधित प्रश्न
Fill in the blank.
When a candle burns, wax melts. Melting of wax is a ________ change.
Tick the most appropriate answer.
Photosynthesis requires
Write true or false
Burning of paper and formation of curd are reversible changes.
Write true or false
Dissolving of solute in a solvent and rusting of iron are both physical changes.
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
Give four reasons why the burning of a magnesium ribbon in the air is considered a chemical change.
Select the chemical changes from the following list of changes
Glowing of an electric bulb.
Water is the universal solvent. Why?
Iron pipes coated with zinc do not get rusted easily.
Mention a few physical properties of a substance.
