Phase Change and Energy

A car mechanic had a sealed bucket containing a substance in the gas phase. She left the bucket outside over the weekend. When she returned, the substance had changed phase, and the substance was in the liquid phase. What happened to the molecules of this substance?

• Before the mechanic left, the molecules were moving away from each other. When she returned, they were moving around each other.

• Before the mechanic left, the molecules were moving around each other. When she returned, they were moving in place.

• Before the mechanic left, the molecules were moving around each other. When she returned, they were moving away from each other.

• Before the mechanic left, the molecules were moving in place. When she returned, they were moving around each other.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

A chef finds a sealed container consisting of an ingredient that goes into his restaurant’s secret sauce. The ingredient’s molecules are moving in place. What will happen if the chef causes the ingredient to change phase by transferring energy into it?

After the phase change, the ingredient’s molecules will move . . .

• faster, and the ingredient will be a solid.

• faster, and the ingredient will be a liquid.

• slower, and the ingredient will be a solid.

• slower, and the ingredient will be a liquid.

Tags

NGSS.MS-PS1-4

Workers 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 workers 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-PS1-2

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?

• 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.

• into the substance, and its molecules would move in place.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

During which phase change of water is the least energy released into the environment?

• water freezing

• ice melting

• water evaporating

• water vapor condensing

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Use the graph to answer this question. Which phase change is taking place if the substance is losing energy (exothermic) from point C to point B?

• melting

• freezing

• evaporation

• condensation

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

All phase changes (changing states) requires energy to be added or taken away.

• True

• False

Tags

NGSS.MS-PS1-4

Look at the graph. Look at the words on the left and bottom. The slanted lines show when energy is transferred in or out and a phase change

(a)   occur.

• does not

• does

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What does "#3" represent on the graph?

• solid phase

• melting

• vaporizing

• condensing

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

A phase change that is ​ (a)   is one that loses heat. An example of this type of change is ​ (b)   ​ which is when a gas cools into a ​ (c)  

• exothermic

• condensation

• liquid

• endothermic

• freezing

• plasma

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4