1.
The temperature at which a substance has enough energy to break a solid from a liquid structure.
Correct Answer
A. Melting point
Explanation
The melting point refers to the temperature at which a substance transitions from a solid to a liquid state. At this temperature, the substance gains enough energy to overcome the forces holding its particles together in a solid structure. This results in the breaking of the solid structure and the formation of a liquid.
2.
The energy a substance uses or releases to change phase
Correct Answer
B. Latent heat
Explanation
Latent heat refers to the energy that a substance uses or releases when it undergoes a phase change, such as from solid to liquid or from liquid to gas. This energy is not associated with a change in temperature but rather with the breaking or forming of intermolecular bonds. It is called "latent" because it is hidden or concealed during the phase change.
3.
A mixture in which particles are evenly distributed but do not dissolve.
Correct Answer
C. Colloidal dispersion
Explanation
A colloidal dispersion is a type of mixture where particles are evenly distributed throughout a medium, such as a liquid or gas, but do not dissolve. In a colloidal dispersion, the particles are larger than the molecules in a solution but smaller than the particles in a suspension. These particles are typically insoluble and can be seen under a microscope. The even distribution of particles in a colloidal dispersion gives it a cloudy or milky appearance. Therefore, colloidal dispersion is the correct answer for the given description.
4.
The energy needed for 1.0 g of a substance to change from a liquid to a gas.
Correct Answer
D. Heat of vaporization
Explanation
The correct answer is "heat of vaporization". Heat of vaporization refers to the amount of energy required for a substance to change from a liquid to a gas at a constant temperature. It is a measure of the strength of intermolecular forces holding the liquid together. When heat is added, these forces are overcome, and the substance changes phase into a gas.
5.
Covalently bonded atoms, arranged to create a clear division of positive and negative charges.
Correct Answer
A. Polar molecule
Explanation
A polar molecule is formed when atoms are covalently bonded in such a way that there is an unequal distribution of electron density, resulting in a clear division of positive and negative charges. This occurs when one atom has a higher electronegativity than the other, causing the shared electrons to be pulled closer to that atom, creating a partial negative charge. The other atom then has a partial positive charge. This separation of charges gives the molecule polarity, meaning it has a positive end and a negative end.
6.
Temperature at which liquid water exerts an upward pressure equal to that of the downward pressure.
Correct Answer
A. Boiling point
Explanation
The boiling point is the temperature at which a liquid, in this case, water, exerts an upward pressure that is equal to the downward pressure. At the boiling point, the vapor pressure of the liquid becomes equal to the atmospheric pressure, causing the liquid to change into its gaseous state. This is why water boils and turns into steam at a specific temperature, which is its boiling point.
7.
The energy used and released when 1.0 g of a substance changes between liquid and solid phases
Correct Answer
A. Heat of fusion
Explanation
The correct answer is "heat of fusion". Heat of fusion refers to the amount of energy required or released when a substance changes from a solid to a liquid phase or vice versa. It is the energy needed to break or form the intermolecular forces holding the particles together in the substance.
8.
A strong attraction between polar molecules that have covalent bonds
Correct Answer
A. Hydrogen bond
Explanation
A hydrogen bond is a strong attraction between polar molecules that have covalent bonds. It occurs when a hydrogen atom, which is covalently bonded to a highly electronegative atom (such as oxygen, nitrogen, or fluorine), is attracted to another electronegative atom nearby. This attraction is due to the difference in electronegativity between the hydrogen atom and the electronegative atom. Hydrogen bonds are responsible for many important biological processes, such as the bonding between DNA strands and the folding of proteins.
9.
The direct change of a substance from solid to gas
Correct Answer
A. Sublimation
Explanation
Sublimation refers to the process in which a substance changes directly from a solid to a gas, without passing through the liquid state. This occurs when the substance is heated and the vapor pressure of the solid exceeds the atmospheric pressure. Unlike melting (solid to liquid) or boiling (liquid to gas), sublimation skips the liquid phase entirely. The correct answer, "sublimation," accurately describes the direct change of a substance from solid to gas.
10.
The ratio of mass to volume
Correct Answer
A. Density
Explanation
Density is the correct answer because it refers to the ratio of mass to volume. Density is a physical property of a substance that describes how much mass is contained in a given volume. It is calculated by dividing the mass of an object by its volume. Density is important in various scientific fields as it helps identify and classify substances, determine their buoyancy, and understand their behavior under different conditions.
11.
Lowering air pressure lowers water's boiling point by ___________.
Correct Answer
A. Reducing the resistance water must overcome to boil
Explanation
Lowering air pressure reduces the resistance water must overcome to boil. When the air pressure is lower, the surrounding pressure on the water decreases, making it easier for water molecules to escape into the gas phase. This reduces the boiling point of water, as less energy is required to break the intermolecular forces and allow the water to transition from a liquid to a gas. Therefore, lowering air pressure effectively reduces the resistance that water faces in order to reach its boiling point.
12.
Water helps regulate body temperature through ____________.
Correct Answer
C. Heat of vaporization
Explanation
Water helps regulate body temperature through heat of vaporization. When the body temperature rises, sweat is produced on the skin. As the sweat evaporates, it absorbs heat from the body, cooling it down. This process is possible due to the high heat of vaporization of water, which means it requires a significant amount of heat to convert water from a liquid to a gas. This property allows water to effectively cool the body and regulate its temperature.
13.
The hydrogen bonds in water _______________.
Correct Answer
A. Create a polar molecule
Explanation
Hydrogen bonds are formed between the positively charged hydrogen atom of one water molecule and the negatively charged oxygen atom of another water molecule. These bonds create an uneven distribution of charge within the water molecule, resulting in a polar molecule. This polarity allows water to dissolve many substances, exhibit surface tension, and have a high boiling point, among other properties. Hence, the hydrogen bonds in water create a polar molecule.
14.
The destruction of nutrients through boiling illustrates a problem associated with ______________.
Correct Answer
B. Water's properties as a solvent
Explanation
When water is boiled, it can cause the destruction of nutrients present in the food being cooked. This is because water acts as a solvent and can dissolve certain nutrients, especially water-soluble vitamins like vitamin C and B vitamins. The high temperatures involved in boiling can further accelerate the breakdown of these nutrients, leading to their destruction. Therefore, the destruction of nutrients through boiling highlights a problem associated with water's properties as a solvent.
15.
An element described as electronegative _________________.
Correct Answer
A. All of the answers are true
Explanation
An element described as electronegative exhibits several characteristics. It exerts a negative charge, meaning it has a tendency to attract electrons towards itself. This property allows it to attract shared electrons in a covalent bond, making it likely to become a part of a polar molecule. Therefore, all of the given answers are true as they describe different aspects of an electronegative element.
16.
The more heat you apply to boiling water, the hotter it becomes.
Correct Answer
B. False
Explanation
When water reaches its boiling point, it cannot get any hotter regardless of the amount of heat applied. At boiling point, water undergoes a phase change from liquid to gas, and the temperature remains constant until all the liquid water has evaporated. Therefore, applying more heat to boiling water does not make it hotter, making the statement false.
17.
Water's unexpectedly high menting point and boiling points are due to hydrogen bonds.
Correct Answer
A. True
Explanation
Water's unexpectedly high melting point and boiling points are due to hydrogen bonds. Hydrogen bonds are formed between the hydrogen atom of one water molecule and the oxygen atom of another water molecule. These bonds are stronger than the usual intermolecular forces found in other substances, such as London dispersion forces. The presence of hydrogen bonds leads to a higher amount of energy required to break the bonds and change the state of water from solid to liquid or from liquid to gas, resulting in higher melting and boiling points compared to other substances.
18.
Hard water results from water's effectiveness as a dispersing medium.
Correct Answer
B. False
Explanation
Hard water does not result from water's effectiveness as a dispersing medium. Hard water is caused by the presence of dissolved minerals, such as calcium and magnesium, in the water. These minerals can cause scaling and other issues with plumbing and appliances. The statement in the question is incorrect.
19.
Water is less dense as a solid than as a liquid.
Correct Answer
A. True
Explanation
Water is less dense as a solid than as a liquid due to its unique molecular structure. When water freezes, the water molecules arrange themselves in a hexagonal lattice, creating open spaces between the molecules. This causes the solid form of water, which is ice, to have a lower density than liquid water. The lower density of ice allows it to float on top of liquid water. This property is crucial for the survival of aquatic organisms during winter months, as it insulates the water below and prevents it from freezing completely.
20.
Water molecules may form an emulsion with nonpolar molecules of another liquid.
Correct Answer
A. True
Explanation
Water molecules are polar, meaning they have a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom. Nonpolar molecules, on the other hand, do not have a charge and are not attracted to water molecules. However, water molecules can form an emulsion with nonpolar molecules by surrounding them and dispersing them throughout the water. This is possible due to the unique properties of water, such as its ability to form hydrogen bonds. Therefore, the statement is true.
21.
It takes more energy to change 5 g of water from a solid to a liquid than to change from a liquid to a gas.
Correct Answer
B. False
Explanation
The statement is false because it actually takes more energy to change water from a liquid to a gas than from a solid to a liquid. This is because the process of changing from a liquid to a gas involves breaking the intermolecular forces between water molecules, which requires a significant amount of energy. On the other hand, changing from a solid to a liquid only requires breaking the weaker intermolecular forces within the solid structure.
22.
The temperature at which a substance has enough energy to break from a solid to a liquid structure.
Correct Answer
A. Melting point
Explanation
The melting point refers to the temperature at which a substance transitions from a solid state to a liquid state. At this temperature, the substance has absorbed enough energy to overcome the forces holding its particles together in a solid structure. The melting point is a characteristic property of a substance and can vary depending on its composition and purity.
23.
The energy a substance uses or releases to change phase.
Correct Answer
A. Latent heat
Explanation
Latent heat refers to the energy that a substance either uses or releases in order to change its phase. This term specifically describes the heat energy involved in the transformation between solid, liquid, and gas states without a change in temperature. It is important to note that latent heat does not cause a change in temperature, but instead alters the molecular structure of the substance.
24.
A mixture in which particles are evenly distributed but do not dissolve.
Correct Answer
A. Colloidal dispersion
Explanation
A colloidal dispersion is a mixture where particles are evenly distributed but do not dissolve. In this type of mixture, the particles are larger than those found in a solution, but smaller than those found in a suspension. The particles in a colloidal dispersion remain suspended in the medium and do not settle out over time. This type of mixture is often opaque or cloudy due to the scattering of light by the particles. Examples of colloidal dispersions include milk, fog, and gelatin.
25.
A ratio of mass to unit volume
Correct Answer
A. Density
Explanation
Density is a measure of how much mass is contained in a given volume. It is calculated by dividing the mass of an object by its volume. Density is a characteristic property of a substance and can be used to identify and compare different materials. Objects with a higher density have more mass in a given volume, while objects with a lower density have less mass in the same volume. Therefore, density is the most appropriate term to describe a ratio of mass to unit volume.
26.
The direct chaange of a substance from a solid to a gas
Correct Answer
A. Sublimation
Explanation
Sublimation refers to the direct change of a substance from a solid to a gas without passing through the liquid phase. This process occurs when the substance absorbs enough heat energy to overcome the forces holding its particles together in the solid state. As a result, the particles gain enough energy to transition directly into the gas phase. Sublimation is a unique phenomenon that can be observed in certain substances, such as dry ice (solid carbon dioxide) and mothballs (solid naphthalene).
27.
The chemical name for a gravy that separates into a liquid portion and chicken fat portion.
Correct Answer
A. Emulsion
Explanation
An emulsion is a mixture of two immiscible substances, such as oil and water, that forms a stable suspension. In the case of a gravy, it can separate into a liquid portion and a chicken fat portion, indicating the presence of two immiscible substances. Therefore, the correct answer is emulsion.
28.
What troublesome product results from water's ability to take apart metallic elements and hold their ions in solution?
Correct Answer
A. Hard water
Explanation
Hard water is the troublesome product that results from water's ability to take apart metallic elements and hold their ions in solution. When water contains high levels of dissolved minerals such as calcium and magnesium, it is classified as hard water. These minerals can cause various issues such as scale buildup in pipes and appliances, reduced efficiency of soaps and detergents, and can leave spots on dishes and fixtures. Therefore, hard water can be considered troublesome due to its negative effects on plumbing systems, cleaning processes, and the overall quality of water for everyday use.
29.
What term describes water that is locked in the chemical structure of food?
Correct Answer
A. Bound water
Explanation
Bound water refers to water molecules that are tightly held within the chemical structure of food. This means that the water is not easily released or separated from the food. Bound water plays a crucial role in food texture and stability, as it affects the moisture content and overall structure of the food. It is different from free water, which is easily separated from the food. Heat of fusion refers to the amount of heat required to convert a substance from solid to liquid state, and tenderacity is not a recognized term in relation to water or food.
30.
How would you describe the orange juice and vegetable oil in a ham glaze, as these two liquids relate to each other/
Correct Answer
A. Immiscible
Explanation
The correct answer is "Immiscible." Immiscible refers to two substances that cannot mix or dissolve in each other. In the context of a ham glaze, orange juice and vegetable oil would be immiscible because they do not blend together and remain as separate layers or droplets.
31.
What word describes water that releases from a zucchini when it's boiled or shredded?
Correct Answer
A. Free
Explanation
When a zucchini is boiled or shredded, the water that is released is described as "free." This means that the water is not bound or restricted in any way, but rather flows freely from the zucchini. The term "immiscible" refers to two substances that cannot be mixed together, which is not applicable in this context. "Defunct" means no longer functioning or in operation, which is unrelated to the water released from a zucchini.
32.
What general word applies to water in its role as a setting for vital chemical reactions?
Correct Answer
A. Medium
Explanation
Water is often referred to as a "medium" in the context of chemical reactions because it provides an environment or setting in which these reactions can occur. Water's unique properties, such as its ability to dissolve many substances and its role as a solvent, make it an ideal medium for various chemical reactions to take place. It facilitates the movement of molecules and ions, allowing them to interact and react with each other. Therefore, the term "medium" accurately describes water's role in supporting vital chemical reactions.
33.
Water's molecules' strong attraction for each other creates what skin-like effect where water contacts another substance?
Correct Answer
A. Surface tension
Explanation
Surface tension is created by the strong attraction between water molecules. This attraction causes the molecules at the surface of the water to be more strongly pulled towards the water molecules below, creating a "skin-like" effect. This effect is observed when water contacts another substance, causing the water to form droplets or create a meniscus. Surface tension allows insects to walk on water and is responsible for capillary action.