Introduction to Gas Laws /KMT

Molecules of an ideal gas at STP exhibit what type of motion?

• Constantly changing speeds and directions.

• Curved paths visible in a cloud chamber.

• Net motion outward from the center of their container.

• Random straight-line motion with slightly varying kinetic energies.

Within an ideal gas, collisions of gas molecules between other gas molecules or with the walls of the container are totally elastic. Which of the following is will occur?

• All molecules slow down as they cancel each other's energy.

• A cooling of the gases and warming of the container will occur.

• A gradual decrease in energy due to entropy will occur.

• No net energy gain or loss will occur.

Which of these is a postulate of kinetic molecular theory?

• Molecules of gases have a finite volume.

• Molecules of gases attract and repel one another.

• Collisions between gas molecules are inelastic.

• The kinetic energy of gas molecules depends on temperature.

According to the kinetic molecular theory of gases, the pressure of the gas is due entirely to the —

• size of the gas particles compared to the size of its container

• mass of the gas particles compared to the size of its container

• force of the collisions of the gas particles with the walls of the container

• moles of gas particles within the walls of the container

A teacher asked students to observe a sealed balloon that was held over a pot of boiling water. Students observed steam begin to surround the balloon and heat up the balloon. The students observed that the balloon increased in volume as it was held over the water. The teacher asked each student to provide an explanation of the phenomenon. Samples of student explanations were recorded below. Which student's explanation correctly explains why the balloons increased in volume?

• Student A

• Student B

• Student C

• Student D