Phase Change 1
Lily 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 Lily’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
The phase of ice
In this phase, you might say molecules shiver.
Solid
A noticeably different form or state of the same substance.
phase
What phase has no visible form?
Gas
A student 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.
Jamil’s bicycle is made of aluminum. When are the aluminum molecules in his bicycle moving?
The aluminum molecules are . . .
always moving.
In this phase, molecules move like dancers in a mosh pit.
gas
The phase when enough energy is removed from a gas.
liquid
When does the weekend start?
3:22 pm Friday
The pull molecules have that is always the same.
molecular attraction
A scientist did a test to compare two substances: substance Q and substance R. At room temperature, both substances are liquid. When the scientist transferred the same amount of energy out of both substances, only one substance changed phase while the other did not. Which substance changed phase, and how did it change?
Substance Q changed phase because the attraction of the molecules was able to overcome their slower movement. Its molecules now move in place.
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.
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.
Do we get a Spring Break?
Yes, March 21-22
How is the kinetic energy of molecules changing when the molecules move faster?
The kinetic energy . . .
is increasing.
Mario is making chocolate. In part of the chocolate-making process, he changed the phase from a liquid to a solid. What happened to the molecules of chocolate when it changed phase?
Before changing phase, the molecules were moving around each other. After changing phase, they were moving in place.
What happens to molecules when their kinetic energy decreases?
They move slower.
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.
What day of the week is today?
Thursday
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?
Substance 1 has a . . .
stronger attraction between its molecules than Substance 2. Its molecules now move in place.
Anh 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.
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.
Scientists digging in a cave found an unknown substance. The scientists found that the substance’s molecules were moving around each other. The scientists increased the speed of the substance’s molecules and caused a phase change. How did the scientists do this, and how did this affect the substance?
The scientists transferred energy . . .
into the substance, and the substance changed into a gas.
How many children does Mr. Adams have?
2