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प्रश्न
What are the forces of cohesion and adhesion?
उत्तर
The force of attraction between the molecules of a similar kind is called a force of cohesion.
Example: The forces between water molecules.
This force of cohesion keeps the molecules of the substance bind together.
The force of attraction between different types of molecules is called a force of adhesion.
Example: When a glass filled with water is emptied some water particles remain stuck to the glass due to the adhesion between water molecules and glass.
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संबंधित प्रश्न
Water cycle is an example of inter conversion of states of water. Explain.
Write true or false for the following statement
The inter-molecular forces are effective at all distances between the two molecules.
Match the following columns
| Column A | Column B | ||
| A. | A molecule is composed of | i. | does not exist free in nature. |
| B. | Ice, water and water vapour | ii. | can vibrate only up to about `10^-10`m from their mean position. |
| C. | An atom | iii. | atoms. |
| D. | Gases | iv. | are the three states of water. |
| E. | The molecules of a solid | v. | occupy space |
One litre of water has 6.02 × 1026 molecules. Estimate the size of a molecule.
Give one difference between atoms and molecules.
Define Intermolecular force
Match the following
| Column A | Column B |
| (a) Solids | (i) Can flow in all directions |
| (b) Sublimation | (ii) The temperature at which a liquid changes into its gaseous state. |
| (c) Boiling point | (iii) Any number of free surfaces. |
| (d) Gases | (iv) Gaps between particles. |
| (e) Intermolecular space | (v) Changes of state from solid to gas. |
State the correct term from A, B, C, D, E or F in List II which represents the – change of state of matter or its relevant property from List I
| List I | List II |
| 1. Solid 'X' to a liquid 'Y' | A: Liquefaction |
| 2. Liquid 'Y' to its vapour 'Z' | B: Vaporization |
| 3. 'Z' to 'Y' | C: Melting |
| 4. 'Y' to 'X' | D: Solidification |
| 5. The temperature at which 'Y' changes to 'Z' | E: Melting Point |
| F: Boiling point |
Write scientific reason.
Lemon sherbat has sweet, sour and salty taste and it can be poured in a glass.
Write scientific reason.
Lemon sherbat has sweet, sour and salty taste and it can be poured in a glass.
