1.
A _____ is a large molecule made of carbon and hydrogen atoms.
Correct Answer
A. Hydrocarbon
Explanation
A hydrocarbon is a large molecule made of carbon and hydrogen atoms. This type of molecule is commonly found in fossil fuels and organic compounds. Hydrocarbons can have different structures and properties depending on the arrangement of carbon and hydrogen atoms. They are important in various industries such as energy production, plastics manufacturing, and pharmaceuticals.
2.
Adding a solute to a solvent _____ the freezing point of a solvent.
Correct Answer
A. Lowers
Explanation
When a solute is added to a solvent, it disrupts the orderly arrangement of the solvent molecules, making it more difficult for them to form solid structures. This results in a decrease in the freezing point of the solvent. Therefore, the correct answer is "lowers".
3.
Air contains 78 percent nitrogen, 21 percent oxygen, and one percent argon. Which gas is the solvent?
Correct Answer
C. Nitrogen
Explanation
In this question, the gasses nitrogen, oxygen, and argon are mentioned along with their respective percentages in the air. The question asks which gas is the solvent. A solvent is a substance that dissolves another substance to form a solution. In the given options, only nitrogen is mentioned to be present in the highest percentage in the air, making it the most abundant gas. Therefore, nitrogen is the correct answer as it acts as the solvent in the air.
4.
What characteristic of water makes it a great solvent?
Correct Answer
D. Polar
Explanation
The characteristic of water that makes it a great solvent is its polarity. Water molecules consist of one oxygen atom and two hydrogen atoms. Due to differences in electronegativity between oxygen and hydrogen, water molecules exhibit a polar nature. This means that one end of the water molecule (the oxygen end) has a slightly negative charge, while the other end (the hydrogen end) has a slightly positive charge. This polarity allows water molecules to attract and interact with other polar molecules and ions, effectively dissolving them. Substances that are polar or ionic tend to dissolve well in water because they can form favorable interactions with the polar water molecules.
5.
Why is it dangerous to take large doses of some nonpolar vitamins?
Correct Answer
C. They are fat soluble and accumulate in body tissues to a toxic level.
Explanation
Taking large doses of fat-soluble vitamins can be dangerous because these vitamins are not easily excreted from the body and instead accumulate in body tissues, and they may accumulate to a toxic level. Unlike water-soluble vitamins, which can be easily eliminated through urine, fat-soluble vitamins can build up to toxic levels in the body if consumed in excessive amounts. This can lead to a condition called hypervitaminosis, which can cause various adverse effects on health.
6.
Gases are _____ in cooler solvents.
Correct Answer
C. More soluble
Explanation
In general, gasses tend to be more soluble in cooler solvents. This is because the solubility of a gas in a solvent is influenced by temperature. As the temperature decreases, the kinetic energy of the gas molecules decreases, causing them to slow down and become more attracted to the solvent molecules. This increased attraction allows for more gas molecules to dissolve in the solvent, making the gas more soluble. Therefore, the correct answer is "more soluble".
7.
Which attributes enable water molecules to dissolve sugar?
Correct Answer
D. Polarity of water and sugar
Explanation
Water molecules are able to dissolve sugar due to water and sugar both being polar. Water molecules have a slight positive charge on the hydrogen atoms and a slight negative charge on the oxygen atom. Sugars have oxygen atoms with partial negative charges and hydrogen atoms with partial positive charges. As such, both water and sugar molecules are polar and can form hydrogen bonds. This polarity allows water molecules to attract and surround the sugar molecules.
8.
Sterling silver contains 92.5 percent silver and 7.5 percent copper. Which substance is the solute?
Correct Answer
D. Copper
Explanation
In the given question, sterling silver is composed of 92.5 percent silver and 7.5 percent copper. A solute is a substance that is dissolved in a solvent to form a solution. In this case, copper is the solute because it is the substance that is being dissolved in the silver to form sterling silver. Therefore, copper is the correct answer.
9.
Because electrons are distributed equally, a hydrocarbon is ____.
Correct Answer
B. Nonpolar
Explanation
A hydrocarbon is nonpolar because the electrons in the molecule are distributed equally. This means that there are no areas of positive or negative charge within the molecule, resulting in a balanced distribution of charge. As a result, hydrocarbons do not readily dissolve in water, which is a polar solvent. Additionally, their nonpolar nature makes them less likely to interact with other polar molecules.
10.
Vitamin C is a(n) _____ compound and dissolves readily in water.
Correct Answer
A. Polar
Explanation
Vitamin C is a polar compound because it dissolves readily in water. Polar compounds have a positive and negative charge distribution, which allows them to interact with the polar water molecules through hydrogen bonding. This property makes them soluble in water. In contrast, nonpolar compounds do not have a charge distribution and do not interact with water molecules, making them insoluble in water. Oily and fat-soluble compounds are nonpolar, so they do not dissolve in water.
11.
Which of the following statements is true?
Correct Answer
D. Nonpolar solvents are useful for dissolving nonpolar solutes.
Explanation
Nonpolar solvents are useful for dissolving nonpolar solutes because like dissolves like. Nonpolar solvents have a similar molecular structure to nonpolar solutes, allowing them to interact and form a solution. This is because nonpolar molecules do not have a charge and are not attracted to polar molecules like water. Therefore, nonpolar solvents are effective in dissolving nonpolar solutes.
12.
Which of the following is the most precise term?
Correct Answer
C. 40 percent juice by volume
Explanation
The term "40 percent juice by volume" is the most precise term because it provides an exact measurement of the juice content in a product. "Supersweet" and "concentrated" are vague terms that do not specify the exact amount of sweetness or concentration. "Dilute" indicates a weakening or reduction in strength, but does not provide a specific measurement. Therefore, "40 percent juice by volume" is the most precise term among the options given.
13.
Which of the following increases the rate of evaporation?
Correct Answer
D. Decreasing attraction between solvent molecules
Explanation
Decreasing attraction between solvent molecules increases the rate of evaporation. When the attraction between solvent molecules is decreased, it becomes easier for the molecules to escape from the liquid phase and enter the gas phase. This leads to an increase in the rate of evaporation.
14.
The process in which water molecules draw ions away from a crystalline solid and into a solution is _____.
Correct Answer
D. Dissociation
Explanation
Dissociation is the process in which water molecules separate or "draw" ions away from a crystalline solid and into solution. This occurs when the water molecules surround and interact with the ions, causing them to become separated from each other and dispersed throughout the solution. The result is the formation of a solution with dissolved ions, allowing for conductivity and other chemical reactions to take place.
15.
Which of the actions increases the rate of dissolving?
Correct Answer
A. Stirring the solution
Explanation
Stirring the solution increases the rate of dissolving because it helps to distribute the solute particles more evenly throughout the solvent. This increases the frequency of collisions between the solute and solvent particles, allowing for a faster dissolution process. Stirring also helps to remove any stagnant layers of saturated solution near the solute, allowing fresh solvent to come into contact with the solute and continue the dissolving process.
16.
A mixture that appears to have the same composition, color, and density and is mixed at the molecular level is called a(n) ____.
Correct Answer
C. Solution
Explanation
A solution is a mixture that appears to have the same composition, color, and density and is mixed at the molecular level. In a solution, the solute particles are evenly distributed throughout the solvent, resulting in a homogeneous mixture. This means that the individual particles of the solute are surrounded by the particles of the solvent, forming a single phase. Solutions can be formed with solids, liquids, or gasses as solutes, and they can be transparent or translucent. Examples of solutions include saltwater, sugar dissolved in water, and air.
17.
_____ is the maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature.
Correct Answer
D. Solubility
Explanation
Solubility is the maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature. It is a characteristic property of a substance and is influenced by factors such as temperature and pressure. By definition, solubility refers to the ability of a substance to dissolve in a solvent, and it is usually expressed in terms of grams of solute per 100 grams of solvent. The solubility of a substance determines its ability to form a homogeneous solution and plays a crucial role in various chemical and physical processes.
18.
A solution that contains all the solute it can hold at a given temperature is _____.
Correct Answer
D. Saturated
Explanation
A solution that contains all the solute it can hold at a given temperature is called saturated. This means that the solution has reached its maximum capacity to dissolve solute particles, and any additional solute added will not dissolve. The concentration of the solute in the solution is at its maximum level, resulting in a stable equilibrium between the dissolved solute and undissolved solute.
19.
____ are compounds that form charged particles.
Correct Answer
C. Electrolytes
Explanation
Electrolytes are compounds that form charged particles. When dissolved in water or melted, electrolytes dissociate into positive and negative ions, allowing them to conduct electricity. This is due to the presence of ions that are free to move and carry an electric charge. In contrast, nonpolar components do not form charged particles and therefore do not conduct electricity. Ions are the charged particles formed by electrolytes, while nonelectrolytes do not form ions when dissolved in water or melted.
20.
Which of the following is a solution?
Correct Answer
D. Salt water
Explanation
Salt water is a solution because it is a homogeneous mixture where salt (the solute) is dissolved in water (the solvent). In a solution, the solute particles are evenly distributed and do not settle out, unlike muddy water or milk. Chlorine is a chemical element and not a solution.