Vocabulary
a group of atoms joined together in a particular way
molecule
1. When a substance changes phases from a liquid to a gas, the freedom of movement of the molecules in the substance _________________.
What is increases
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)
When a substance condenses, the substance changes from a gas to a liquid. During this process what happens to the movement of the molecules?
What is slower and closer together
In the phase change simulation, what was being added and subtracted from the substance to make it change phases?
What is energy
the energy that an object has because it is moving
Kinetic energy
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.
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
the temperature at which a substance changes from the solid phase to the liquid phase
melting point
Name the change... liquid to gas
evaporation
When talking about molecules and phase changes, what does Freedom of Movement mean?
What is the way molecules in a substance move around relative to each other.
What happens to molecules kinetic energy when they move slower?
It decreases
What happens to molecules when their kinetic energy decreases?
They move slower
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.
How is the kinetic energy of molecules changing when the molecules move faster?
The kinetic energy . . .
is increasing
What does "molecular scale" mean?
What is substances can not be seen with the human eye. They need an instrument to assist.
You put water in a pot and heat it over the stove. After a few minutes you see steam rising from the pot. how did the behavior of the molecules change from the time you put the water in the pot to when you saw steam?
What is the speed of the molecules increased and spread out from one another
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.
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.
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.
Matter is defined as anything that has ____________ and _____________.
What is mass and volume
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
If you had a large chunk of a frozen substance and you wanted to force a phase change to make it a liquid, what would you need to do?
What is transfer energy to the substance
A cook had a jar containing a sweet food and a jar containing a sour food. The image above shows the sweet and sour foods. 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.
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