Vocabulary
Energy Transfer
Phase Change
Molecular Attraction
Key Concepts
100

a group of atoms joined together in a particular way

molecule

100

What happens to molecules movement when you transfer energy in?

They move faster

100

When water was 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?

Solid-the molecules were moving in place. After, the molecules were moving around each other. (Liquid)

100

You have two substances, one with a strong and one with a weak attraction, and both are liquids right now.  Which would you need to add less energy to get it to change to a gas?

The one with the weak attraction

100

the tiny pieces that all matter—all the stuff in the world—is made of

atoms

200

the energy that an object has because it is moving

Kinetic energy

200

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?

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

200

Andy measured the temperature of a pond near his house. Before he left for school, the water in the pond was 18°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 started moving faster

200

the temperature at which a substance changes from the solid phase to the liquid phase

melting point

200

Name the change... liquid to gas

evaporation

300

the way molecules in a substance move around relative to each other

freedom of movement

300

What happens to molecules kinetic energy when they move slower?

It decreases

300

What happens to molecules when their kinetic energy decreases?

They move slower

300

Payont 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 Payton's substance if she transfers energy into the substance and causes a phase change?

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

faster, and the substance will be a gas.

300

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

The kinetic energy . . . 

is increasing

400

to provide evidence that goes against a claim

refute

400

Mario is making chocolate. At the beginning of the chocolate-making process, the molecules were moving around each other. After the chocolate cooled the molecules moved in place . What was the phase change?


Liquid to solid

400

The fuel tank of an airplane has a device that measures the fuel’s temperature. Before the airplane took off, the temperature of the fuel was 27°C. After the airplane had been flying for one hour, the temperature of the fuel had decreased to 3°C. Which of the following must have happened to the molecules of the fuel?


The molecules started moving slower.

400

At room temperature, two substances are liquids. 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?

Substance 1 has a . . .

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

400

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 . . .

A.slower, and they move away from each other.

B.slower, and they move around each other.

C.faster, and they move around each other.

D.faster, and they move in place. 

B.slower, and they move around each other.

500

a pull between two molecules that is always the same for a substance

molecular attraction

500

Scientists put a sample of water into a sealed tank. Water can be a solid, liquid, or gas. At first, the molecules moving around each other. Then, the scientists transferred energy into the substance, and the molecules moved apart. What was the phase change?


liquid to gas

500



A student left a sealed jar of ice (a solid) outside. Twelve hours later, the water had changed phase and was a liquid.

What happened to the water molecules?

A.Before: moving in place 

After: moving around each other

B.Before: moving around each other

After: moving away from each other

C.Before: moving around each other

After: moving in place


A.Before: moving in place 

After: moving around each other

500

A cook had a jar containing a sweet food and a jar containing a sour food. The sweet food molecules have weaker attraction compared to the sour ones. At room temperature, both foods are liquids. The same amount of energy was transferred into both substances. Later, one of the foods had changed phase while the other had not. Which food changed phase, and how did it change?

 The sweet food changed because the molecules were able to move fast enough to overcome the attraction between them. Its molecules now move away from each other.

500

You have two substances, one with a strong and one with a weak attraction, and both are liquids right now.  Which would you need to remove less energy to get it to change to a solid?

The one with the strong attraction