What does Boyle's Law relate to in terms of physical properties of gases?

Boyle's Law specifically describes the relationship between the pressure and volume of a gas held at a constant temperature. This law states that if the temperature remains constant, the pressure of a gas is inversely proportional to its volume. In practical terms, this means that as the volume of a gas decreases, the pressure increases, and vice versa. This principle is crucial in various applications, such as understanding how syringes work or the behavior of gases in different environments.

In contrast, the other choices reflect different gas laws or concepts. For example, the relationship between volume and temperature is described by Charles's Law, which states that at constant pressure, the volume of a gas increases with an increase in temperature. The relationship between temperature and pressure is addressed in Gay-Lussac's Law, highlighting how pressure increases with temperature at a constant volume. Density and mass pertain to different aspects of substances and do not fall under the specific conditions of gas behavior dictated by Boyle's Law. Thus, the correct choice accurately captures the essence of Boyle's Law.