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