1.
What phases are shown in the three images below?
Correct Answer
B. Image 1 is liquid, image 2 is solid, and image 3 is gas.
Explanation
The answer is Image 1 is liquid, image 2 is solid, and image 3 is gas because the images depict the different phases of matter. In image 1, the particles are close together but still able to move freely, indicating a liquid state. In image 2, the particles are tightly packed and arranged in a fixed pattern, indicating a solid state. In image 3, the particles are spread apart and moving freely, indicating a gaseous state.
2.
What is the phase of water when its temperature is 150°C?
Correct Answer
C. Gas
Explanation
At a temperature of 150°C, water is in the gas phase. This is because water boils and turns into steam at 100°C, so at a higher temperature like 150°C, it would definitely be in the form of a gas.
3.
What is true of a gas?
Correct Answer
C. A gas has a changeable shape and will expand or shrink to fill any container.
Explanation
A gas does not have a fixed shape, meaning it can change its shape depending on the container it is in. Additionally, a gas is able to expand or shrink to fill any container it is placed in. This is due to the fact that gas particles are not tightly packed together and are free to move around.
4.
An unopened bottle of water is taken out of the refrigerator and placed on a table. After a while, the bottle is covered with droplets of water. What phase change has occurred?
Correct Answer
D. Condensation
Explanation
When a bottle of water is taken out of the refrigerator and placed on a table, the temperature of the surroundings is higher than the temperature inside the bottle. As a result, the water vapor present in the air around the bottle comes into contact with the cold surface of the bottle and loses heat. This causes the water vapor to condense and form droplets of water on the bottle's surface. Therefore, the phase change that has occurred in this scenario is condensation.
5.
Molten lava pours from a volcano in Hawaii. After a few hours, the liquid lava hardens into a shiny gray rock. Which phase change has taken place?
Correct Answer
B. Freezing
Explanation
The phase change that has taken place is freezing. This is because the molten lava, which was in its liquid state, has cooled down and solidified into a shiny gray rock. Freezing refers to the process of a substance changing from a liquid to a solid state due to a decrease in temperature.
6.
The temperature at which a liquid changes to a gas is called
Correct Answer
B. Boiling point
Explanation
The temperature at which a liquid changes to a gas is called the boiling point. This is the point at which the vapor pressure of the liquid equals the atmospheric pressure, causing the liquid to rapidly vaporize and form bubbles. It is a characteristic property of each substance and can vary depending on factors such as atmospheric pressure.
7.
To change from a gas to a liquid is called
Correct Answer
A. Condensation
Explanation
Condensation is the process in which a gas changes into a liquid state. This occurs when the gas loses heat energy and its particles slow down, coming closer together to form a liquid. Evaporation, on the other hand, is the process in which a liquid changes into a gas state. Precipitation refers to the falling of condensed water vapor in the atmosphere, such as rain or snow. Sublimation is the direct transition of a substance from a solid to a gas without passing through the liquid state. Therefore, the correct answer is Condensation.
8.
Change from a liquid to a solid is called
Correct Answer
A. Freezing
Explanation
The process of changing from a liquid to a solid is called freezing. This occurs when the temperature of a substance drops below its freezing point, causing the particles to slow down and arrange themselves into a more ordered structure. During freezing, the substance loses heat energy, and its molecules come closer together, forming a solid state.
9.
Which phase always fills its container?
Correct Answer
A. Gas
Explanation
Gas always fills its container because its particles have high kinetic energy and are not held together by strong forces. This allows them to move freely and spread out to occupy the entire available space. Unlike solids and liquids, gases do not have a fixed shape or volume, and they can easily expand or compress to fill any container they are placed in. Plasma, on the other hand, is a highly ionized gas and also exhibits similar behavior, but it is not as commonly encountered as gases in everyday life.
10.
Which phases do not fill its containers?
Correct Answer
D. A and B
Explanation
The phases that do not fill their containers are the solid and liquid phases. Solids have a fixed shape and volume, so they do not fill their containers. Liquids, although they do not have a fixed shape, have a fixed volume and therefore do not completely fill their containers either. On the other hand, gases have neither a fixed shape nor a fixed volume, so they are able to fill their containers completely.
11.
What happens when water boils?
Correct Answer
A. It becomes water vapor
Explanation
When water boils, it reaches its boiling point and undergoes a phase change from a liquid to a gas. The heat applied to the water causes the water molecules to gain energy and move faster, eventually breaking the intermolecular forces holding them together. As a result, the water molecules escape into the air as water vapor. Therefore, the correct answer is "It becomes water vapor."
12.
What is a single homogeneous physical state referred to as?
Correct Answer
D. pHase
Explanation
A single homogeneous physical state is referred to as a phase. This term is used to describe a specific form of matter that has distinct properties and characteristics. It can be solid, liquid, or gas, depending on the temperature and pressure conditions. The concept of phase is important in understanding the behavior and transformations of matter.
13.
Which phase change results from a solid going directly into the gaseous phase?
Correct Answer
A. Sublimation
Explanation
Sublimation is the phase change that occurs when a solid directly transitions into the gaseous phase without passing through the liquid phase. This process happens when the substance's vapor pressure exceeds the atmospheric pressure at a given temperature. Examples of substances that undergo sublimation include dry ice (solid carbon dioxide) and mothballs (naphthalene). Therefore, sublimation is the correct answer to the question.
14.
The intersection of the solid, liquid, and gaseous lines on a phase diagram is known as the
Correct Answer
B. Triple point
Explanation
The intersection of the solid, liquid, and gaseous lines on a phase diagram is known as the triple point. At this point, all three phases of a substance coexist in equilibrium. It is the temperature and pressure at which the solid, liquid, and gas phases can coexist simultaneously. The triple point is a unique point on the phase diagram and can be used to define the temperature and pressure scales.
15.
The phase of the substance is referred to as what beyond the critical point?
Correct Answer
B. Supercritical fluid
Explanation
Supercritical fluid is the phase of a substance beyond its critical point. At this point, the substance exists in a state where it has properties of both a gas and a liquid. It is above its critical temperature and pressure, allowing it to have a high density and low viscosity like a liquid, while also having the ability to diffuse through solids and fill containers like a gas. This unique state of matter is referred to as a supercritical fluid.