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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.
संबंधित प्रश्न
Fill in the blank.
Heat is .................... by a gas during the process of condensation.
Write true or false for the statement
Decomposition of leaves is a fast change.
Write short answer.
Give two examples of periodic changes
What role does energy play in initiating a chemical change ?
State whether the following is physical or chemical changes.
shaping a piece of glass —
True or false
Is melting of ice a reversible 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
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
State what is meant by the term – interconversion of matter. Is interconversion of matter a physical change or a chemical change.
Select the chemical changes from the following list of changes
Vaporisation of water into water vapour.
