PC 3.5 ET

The molecules of this substance are moving around each other. What phase is this substance in?

• Solid

• Liquid

• Gas

According to the diagram, which substance has a strong attraction?

• Substance A

• Substance B

According to the diagram, which substance has a weak attraction?

• Substance A

• Substance B

If you are transferring energy into a substance, what does that cause the molecules to do?

• Move faster

• Move slower

A scientist transfers the same amount of energy into both substances. One substance changes phase, but the other does not. Which chemical changed phase, and why did it change?

• Substance A changed phase because its molecules were able to move fast enough to overcome the attraction between them. It is now a gas.

• Substance B changed phase because the molecules were able to move fast enough to overcome the attraction between them. It is now a gas.

If you are transferring energy into a liquid, what phase does it change into?

• Solid

• Gas