Chapter 14.1, Problem 1BYL

To determine

The reason why a gas under constant pressure expands and contracts with changes in temperature with the help of a figure.

Answer to Problem 1BYL

When temperature increases, the kinetic energy of molecules also increases. It results in the expansion of gas molecules. When temperature decreases, the kinetic energy of molecules decreases, and it results in contraction.

Explanation of Solution

When the temperature of a gas increases, it increases the energy of molecules also. Therefore, a huge volume is required for accommodating the same amount of gas. The cooling of gas leads to the decrease in the kinetic energy and motions of molecules. As a result, they can be packed into a smaller volume. The density of the gas will be high, and it will lead to sinking.

The temperature and volume of gas are directly proportional when the pressure is constant. It indicates that the doubling of temperature also leads to the doubling of volume. This relationship is known as Charles’s Law and it is considered as one of the basic law that governs the behaviour of gases.