Phase Change End-of-Unit Assessment

Front

A student left a sealed jar of water outside her home. Water can be a solid, liquid, or gas. When she put it outside, the water was a solid. Twelve hours later, the water had changed phase and was a liquid. What happened to the water molecules?

Back

Before the student left, the molecules were moving in place. After, the molecules were moving around each other.

Front

Lily is doing a science experiment with a substance in a sealed jar. At first, the substance’s molecules are moving around each other. What will happen to Lily’s substance if she transfers energy into the substance and causes a phase change? After the phase change, the substance’s molecules will move . . .

Back

faster, and the substance will be a gas.

Front

What happened to the water molecules while Anh was at school when the temperature of the pond increased from 18°C?

Back

The molecules started moving faster.

Front

A scientist has a container with a substance inside. At first, the molecules in the substance move away from each other. Later, the molecules move around each other. What change did the scientist observe in the substance?

Back

Before, the substance was a gas. Later, it was a liquid.

Front

Which object has molecules that are moving?

Back

Both have molecules that are moving.

Front

What happens to molecules when their kinetic energy decreases?

Back

They move slower.

Front

Mario is making chocolate. In part of the chocolate-making process, he changed the phase from a liquid to a solid. What happened to the molecules of chocolate when it changed phase?

Back

Before changing phase, the molecules were moving around each other. After changing phase, they were moving in place.

Front

The diagram above describes the movement of molecules in a substance used to make fuel. What change did the fuel scientist observe in the substance?

Back

Before the process, the substance was a liquid. After the process, it was a gas.

Front

When are the aluminum molecules in Jamil’s bicycle moving?

Back

always moving.

Front

How is the kinetic energy of molecules changing when the molecules move faster?

Back

is increasing.