Question

there are 300 light particles in an airtight container. which adjustment would increase the speed of the particles? (1 point)
keeping the volume constant and cooling the container
keeping the volume constant and replacing the light particles with heavy particles
keeping the pressure constant and increasing the temperature
keeping the temperature constant and increasing the container volume

Explanation:

Step1: Recall kinetic - molecular theory

The average kinetic energy of gas particles is directly proportional to the temperature of the gas. The speed of gas particles is related to their kinetic energy ($KE=\frac{1}{2}mv^{2}$).

Step2: Analyze each option

• Keeping the volume constant and cooling the container: Cooling decreases temperature, which decreases the kinetic energy and speed of particles.
• Keeping the volume constant and replacing light particles with heavy particles: This changes the mass of particles, not their speed directly related to temperature.
• Keeping the pressure constant and increasing the temperature: According to the ideal - gas law and kinetic - molecular theory, increasing temperature at constant pressure increases the average kinetic energy of particles, thus increasing their speed.
• Keeping the temperature constant and increasing the container volume: At constant temperature, the kinetic energy of particles is constant, and changing the volume does not affect the speed of particles.

Answer:

keeping the pressure constant and increasing the temperature