Chapter 10, Problem 1E

Interpretation Introduction

To write: The basic postulates of kinetic molecular theory and to relate how the concept of pressure is arrived from this theory.

Answer to Problem 1E

Solution:

The kinetic molecular theory has 6 postulates. As per the theory, when the gas molecules colloid with wall they create pressure.

Explanation of Solution

Postulates of kinetic molecular theory:

1. The gas particles are considered to be very small; the volume occupied by the gas molecules is negligible in comparison to volume of the gas or container.
2. At ordinary temperature and pressure, there is no force of attraction between the particles of a gas.
3. Gases consist of large number of very small particles (molecules or atoms), and are in constant random motion.
4. The gas particles move in all possible directions in straight lines. During their motion, they collide with other gas molecules and also with walls of the container.
5. The collisions of the gas molecules are perfectly elastic, so the net energy of the gas molecules remains the same before and after collision.
6. The average kinetic energy of the gas molecules and its absolute temperature are directly proportional each other.

Concept of pressure according to kinetic molecular theory:

Pressure is defined as force exerted per unit area. According to this theory, gas molecules move in random direction and collide with other molecules and with the walls of the container, when the gas molecules colloids with walls, it creates pressure.

Conclusion

The kinetic molecular theory has 6 postulates. As per the theory, when the gas molecules colloid with wall they create pressure.