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प्रश्न
Define a pure substance. How many types of pure substances do you know?
उत्तर
Pure substances: “A substance of a definite composition which has consistent properties throughout, is called a pure substance” Types of pure substances: Pure substances are of two types
(i) Elements
(ii) Compounds
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संबंधित प्रश्न
Give one example for the following types of mixtures:
liquid-gas homogenous mixture
Give two examples of the following.
Non-metals which are lustrous
Match the Columns:
| Column A | Column B | ||
| (a) | Metals | (i) | Non-Reactive |
| (b) | Molecules | (ii) | Brittle |
| (c) | Non-Metals | (iii) | Lustrous |
| (d) | Noble Gases | (iv) | Smallest unit of Compound |
Complete the statement – an element is a pure substance made up of ____________ atoms.
State why brass is considered as a homogenous mixture while a mixture of iron & sulphur – heterogenous.
Select the correct answer from A, B, C, D & E for the statement given below :
A diatomic molecule.
Match the separation of components in List I with the most appropriate process in List II.
| List I | List II |
| 1. Naphthalene from naphthalene & sodium chloride. | A: Separating funnel |
| 2. Cream from milk. | B: Sublimation |
| 3. Kerosene oil from kerosene oil & water. | C: Boiling |
| 4. Lead nitrate from an aqueous solution of lead nitrate. | D: Centrifugation |
| 5. Ammonia from an aqueous solution of ammonia. | E: Distillation |
Higher Order Thinking Skills.
List out the metals, non-metals and metalloids which you use in your house, schools. Compare their properties.
Name the element which is used for making computer chips.
How are elements classified?
