PADI Divemaster Certification Practice Exam

How does an increase in gas temperature affect its pressure in a nonflexible container?

1. Pressure decreases

2. Pressure remains unchanged

3. Pressure can only increase

4. Pressure may increase or decrease

The correct answer is: Pressure can only increase

In a nonflexible container, if the temperature of a gas increases, the kinetic energy of the gas molecules also increases. This means that the molecules move more vigorously and collide with the walls of the container more frequently and with greater force. According to Gay-Lussac's Law, which states that the pressure of a gas is directly proportional to its absolute temperature (when volume is held constant), an increase in temperature results in an increase in pressure. Thus, in this scenario, the only outcome is an increase in pressure, provided that the volume remains fixed, which is characteristic of a nonflexible container. This dynamic is a fundamental principle of gas behavior that underlines much of the understanding of gas laws in both diving and general physics contexts.