What is the relationship defined by Boyle's Law?

• A. P1V1 = P2V2; pressure increases as volume decreases
• B. P1V1 = P2V2; temperature is constant
• C. P1V1 = P2V2; volume is inversely proportional to pressure
• D. P1V1 = P2V2; volume decreases as temperature increases

Answer: (C)

Boyle's Law describes the inverse relationship between the pressure and volume of a gas when the temperature is held constant. The correct interpretation reflects that as the volume of the gas decreases, the pressure increases, provided the temperature does not change. This is articulated mathematically by the equation ( P_1V_1 = P_2V_2 ), showing the product of pressure and volume remains constant during the process.

The essential point is that if you consider a gas in a closed container and you reduce its volume (by compressing the gas), the molecules have less space to move around, which leads to more frequent collisions with the walls of the container, thus increasing the pressure. This illustrates the inverse proportionality — as one variable increases, the other decreases.

When assessing the temperature connection, Boyle's Law explicitly assumes a constant temperature, distinguishing it from laws that describe the behavior of gases when temperature is variable. Therefore, the relationship under Boyle's Law fundamentally centers on how pressure and volume interact rather than the effect of temperature on gas behavior.