No, increasing volume generally decreases pressure, assuming the amount of gas and temperature remain constant. This relationship is described by Boyle's Law.
Boyle's Law Explained
Boyle's Law states that the pressure of a given mass of an ideal gas is inversely proportional to its volume at a constant temperature. In simpler terms, if you increase the volume of a container holding a gas, the pressure exerted by that gas will decrease proportionally. Conversely, decreasing the volume will increase the pressure.
Mathematically, Boyle's Law is expressed as:
P₁V₁ = P₂V₂
Where:
- P₁ = Initial pressure
- V₁ = Initial volume
- P₂ = Final pressure
- V₂ = Final volume
Why Does This Happen?
Gas molecules are in constant, random motion. They exert pressure by colliding with the walls of their container. When the volume of the container increases, the molecules have more space to move around, resulting in fewer collisions with the walls per unit of time. Since pressure is directly related to the frequency and force of these collisions, the overall pressure decreases.
Example:
Imagine a balloon. If you increase the volume of the balloon by inflating it further, the pressure inside the balloon will decrease (relative to what it would have been at the original, smaller volume if you had added the same amount of air to the smaller balloon). While you are adding air and increasing volume, the pressure relationship being discussed focuses on just the volume change in isolation from the increase in the amount of gas. If, instead, you kept the balloon's volume the same and added air, the pressure inside would increase.
Important Considerations
Boyle's Law is an idealization that holds true under specific conditions:
- Constant Temperature: The temperature of the gas must remain constant. Changes in temperature will affect the pressure independently.
- Constant Amount of Gas: The number of gas molecules must remain constant. Adding or removing gas will directly affect the pressure.
- Ideal Gas Behavior: Boyle's Law is most accurate for gases that behave ideally. Real gases may deviate from this behavior, especially at high pressures or low temperatures.
Summary
Increasing the volume of a gas decreases its pressure, provided the temperature and amount of gas remain constant. This inverse relationship is described by Boyle's Law.
