Chapter 14.1, Problem 1BYL

To determine

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

Answer to Problem 1BYL

When temperature increases, the kinetic energy of molecules also increases and it results in the expansion of gas molecules. When temperature decreases, 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 as well. Therefore, a huge volume is required for accommodating the same amount of gas. The cooling of gas leads to the decrease in 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, which will lead to sinking.

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