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प्रश्न
What are the characteristic properties of a pure substance? Why do we need them?
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उत्तर
Pure substance : Pure substances have a definite set of properties such as boiling point, melting point, density, etc. They are all homogeneous i.e., their composition is uniform throughout the bulk. Both elements and compounds are pure substances.
Pure substances are needed to :
- Manufacture medicines.
- To prepare chemicals in industry.
- For scientific purposes.
- To maintain the good health of human beings.
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संबंधित प्रश्न
What is a mixture ? Give two example of mixtures.
Define the following:
Homogeneous mixture
Give two examples of the following type of mixture.
solid-liquid
Write “true” or “false” for the following statement
A pure substance consists of only one kind of atom or molecule.
State whether the following statement is true or false. If false write – the correct statement.
Components in a mixture are present in a definite proportion.
State whether the following statement is true or false. If false write – the correct statement.
Heterogeneous mixtures have different composition and properties throughout the mixture.
Differentiate between a homogenous and a heterogeneous mixture with one example of each in the (a) solid-solid (b) solid-liquid If (c) liquid-liquid state of the mixture.
Which of the following are physical changes?
(i) Melting of iron metal
(ii) Rusting of iron
(iii) Bending of an iron rod
(iv) Drawing a wire of iron metal
A mixture of two or more miscible liquids, for which the difference in the boiling points is less than 25 K can be separated by the process called ______.
Tabulate Differences between mixtures and compounds.
