Phase Change Amplify - End of Unit Study Guide

Scientists find two substances. One is a toxic chemical. The other is a safe chemical. Both chemicals are liquids at room temperature. As a test, the scientists transfer the same amount of energy OUT OF the two containers and find that only the toxic chemical changes phase. How is the toxic chemical different from the safe chemical?

• weaker attraction between its molecules than the safe chemical. Its molecules now move in place.

• weaker attraction between its molecules than the safe chemical. Its molecules now move around each other.

• stronger attraction between its molecules than the safe chemical. Its molecules now move away from each other.

• stronger attraction between its molecules than the safe chemical. Its molecules now move in place.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Cesar and Ming were investigating a see-through container of water. Water can be a solid, liquid, or gas. At first, Cesar and Ming said the water molecules were moving in place. Later , the water molecules were moving around each other. What change did they observe to the water?

• At first, the water was a gas. Later, it was a liquid.

• At first, the water was a liquid. Later, it was a solid.

• At first, the water was a solid. Later, it was a liquid.

• At first, the water was a liquid. Later, it was a gas.

Tags

NGSS.MS-PS1-4

A company uses a substance that is a solid under normal conditions. This substance will be used in extreme conditions, which could make the substance’s molecules move faster and cause a phase change. How would this phase change occur, and how would the molecules of the substance be affected under these extreme conditions?

Energy would be transferred . . .

• OUT of the substance, and its molecules would move away from each other.

• OUT of the substance, and its molecules would move around each other.

• INTO the substance, and its molecules would move around each other.

• INTOthe substance, and its molecules would move in place.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-5

The image above shows information about two different substances in sealed containers. At room temperature, both substances are liquids. 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. Its molecules now move away from each other.

• Substance A changed phase because the weak attraction between its molecules allowed them to move faster. Its molecules now move away from each other.

• Substance B changed phase because the molecules were able to move fast enough to overcome the attraction between them. Its molecules now move away from each other.

• Substance B changed phase because the strong attraction between molecules made their movement slower. Its molecules now move in place.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Refrigerators are able to transfer energy out of a substance. At first, the substance is a gas. The refrigerator changes the phase of the substance by transferring energy out of it. How does this change affect the substance’s molecules?

After the phase change, the molecules move . . .

• slower, and they move away from each other.

• slower, and they move around each other.

• faster, and they move around each other.

• faster, and they move in place.

Tags

NGSS.MS-PS1-4

Maggie 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?

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

• Before the student left, the molecules were moving around each other. After, the molecules were moving away from each other.

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

• Before the student left, the molecules were moving away from each other. After, the molecules were moving around each other.

Tags

NGSS.MS-PS1-4

Divers found two substances on the bottom of the ocean. At room temperature, both substances are liquid. Scientists then transferred the same amount of energy out of both substances. When a scientist checked again, Substance 1 had changed phase, but Substance 2 had not. How are Substances 1 and 2 different?

• weaker attraction between its molecules than Substance 2. Its molecules now move in place.

• weaker attraction between its molecules than Substance 2. Its molecules now move around each other.

• stronger attraction between its molecules than Substance 2. Its molecules now move away from each other.

• stronger attraction between its molecules than Substance 2. Its molecules now move in place.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Tom measured the temperature of a pond near his house. Before he left for school, the water in the pond was 15°C. When he came home from school, the temperature of the pond was higher than it was in the morning. What happened to the water molecules while he was at school?

• The molecules got closer together.

• The molecules started moving faster.

• The water lost cold molecules.

• The molecules became larger.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A scientist had a container of two substances.  The image shows these substances.  At room temperature, both substances are liquids.  The same amount of energy was transferred INTO both substances.  After a few hours, one of the substances had changed phase, while the other did not.  Which substance would most likely change phases, and explain why?

• The substance #1 changed because the molecules were able to move fast enough to overcome the attraction between them. Its molecules now move away from each other.

• The substance #1 changed because the strong attraction between molecules made their movement slower. Its molecules now move around each other.

• The substance #2 changed because the weak attraction between molecules let them move faster. Its molecules now move away from each other.

• The substance #2changed because the molecules were able to move fast enough to overcome the attraction between them. Its molecules now move in place.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A scientist has two substances that she is testing in her lab: a pink substance and a green substance. At room temperature, both substances are liquids. The scientist transferred the same amount of energy into both substances. She finds only the pink substance changed phase. How is the pink substance different from the green substance?

The pink substance has a . .

• weaker attraction between its molecules than the green substance. Its molecules now move away from each other.

• weaker attraction between its molecules than the green substance. Its molecules now move in place.

• stronger attraction between its molecules than the green substance. Its molecules now move away from each other.

• stronger attraction between its molecules than the green substance. Its molecules move around each other.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5