Properties of Liquids:
There are some simple properties of liquids e.g.” dispersion, pressure, development, movement atoms, spaces between them, intermolecular powers, and active vitality in view of dynamic sub-atomic hypothesis.” We can use the kinetic molecular theory to account for the simple properties of liquids.
- Diffusion. The diffusion in liquids takes place because the molecules move from one place to another due to K.E. The restricted movement of the molecule reduces the rate of diffusion e.g. a drop of ink when added to water diffuses slowly due to relatively small empty spaces between the molecules. The dissemination between firmly pressed atoms of fluids is eased back because of less impact between them.
- Compression (effect of pressure). A liquid cannot be compressed significantly by increasing the pressure because the molecules are already in close contact with one another e.g. an increase of pressure from one to two atmospheres reduces the volume of water to 0.0045 percent which is negligible. However, the pressure reduces the volume of gas up to 50 percent.
- Expansion (effect of temperature). The liquids expand on heating because the intermolecular forces between them decrease. Moreover, the increase in temperature increases the effective collisions between the molecules. If the temperature is decreased, the contraction of volume takes place. This property is useful for making thermometers, e.g. mercury expands in the capillary tube. As the volume of the capillary is much less than the volume of the bulb containing mercury, a small expansion gives a large movement of mercury thread.
- The motion of molecules. The molecules move with lesser speed due to larger forces of attraction among them, As a result, they have lesser kinetic energy. However, the kinetic energy increases with the increase of temperature.
- Spaces between them. The molecules forming the liquid states are fairly close to each other. There is very little space between them. As a result, the numbers of collisions among the molecules are moderate. Therefore, the average kinetic energy is also moderate.
- Intermolecular forces. The attractive forces existing between the individual particles of a substance are called intermolecular forces. The physical properties of fluids, for example, breaking point, vapor weight, surface pressure, consistency and warmth of vaporization rely on the quality of intermolecular appealing powers.
- Kinetic Energy based on Kinetic Molecular Theory. According to the kinetic molecular theory, the molecules due to strong intermolecular attractions have minimum movements and minimum collisions. Let us consider the example of water, as the molecules are closer to each other and have strong forces of attractions due to hydrogen bonding so they have low kinetic energy.