Which statement explains the molecular changes that occur in an enclosed gas as the pressure increases and the temperature is held constant?
1. An increase in pressure causes particles to move closer together, increasing the volume.
2. An increase in pressure causes particles to move farther apart, decreasing the volume.
3. An increase in pressure causes particles to move closer together, decreasing the volume.
4. An increase in pressure causes particles to move farther apart, increasing the volume.
3. An increase in pressure causes particles to move closer together, decreasing the volume.
The correct statement that explains the molecular changes that occur in an enclosed gas as the pressure increases and the temperature is held constant is:
3. An increase in pressure causes particles to move closer together, decreasing the volume.
To determine the correct statement that explains the molecular changes in an enclosed gas as the pressure increases while keeping the temperature constant, we need to understand the basic principles of how gases behave.
When the pressure on a gas increases while the temperature is held constant, the volume of the gas will decrease. This is known as Boyle's law. According to Boyle's law, there is an inverse relationship between pressure and volume: as pressure increases, volume decreases, and vice versa.
Now, let's evaluate each statement based on this understanding:
1. An increase in pressure causes particles to move closer together, increasing the volume.
This statement is incorrect because as the pressure increases, the volume of the gas actually decreases. The particles do come closer together, but they don't increase the volume.
2. An increase in pressure causes particles to move farther apart, decreasing the volume.
This statement is also incorrect. When pressure increases, the particles do not move farther apart; instead, they get closer, decreasing the volume.
3. An increase in pressure causes particles to move closer together, decreasing the volume.
This statement is correct. As the pressure increases, the gas particles move closer together, which subsequently decreases the volume of the gas.
4. An increase in pressure causes particles to move farther apart, increasing the volume.
This statement is incorrect. An increase in pressure does not cause the particles to move farther apart. Instead, it results in the particles moving closer together, leading to a decrease in volume.
Therefore, the correct statement that explains the molecular changes in an enclosed gas as the pressure increases while the temperature is held constant is:
3. An increase in pressure causes particles to move closer together, decreasing the volume.