Unit 8 - Particles In Solution

1. Substances that do not ionize in water and cannot conduct electricity are called ______.

Nonelectrolytes

Electrolytes

Dissociated

Nonions

Nonelectrolytes are substances that do not ionize in water and therefore cannot conduct electricity. When a substance does not dissociate into ions in water, it does not form charged particles that can carry an electric current. Instead, it remains in its molecular form and does not contribute to the conductivity of the solution. Therefore, nonelectrolytes are unable to conduct electricity.

Explanation

Nonelectrolytes are substances that do not ionize in water and therefore cannot conduct electricity. When a substance does not dissociate into ions in water, it does not form charged particles that can carry an electric current. Instead, it remains in its molecular form and does not contribute to the conductivity of the solution. Therefore, nonelectrolytes are unable to conduct electricity.

2. Vitamin C is a(n) ____ compound and dissolves readily in water.

Nonpolar

Polar

Fat soluble

Oily

Vitamin C is a polar compound because it readily dissolves in water. Polar compounds have a positive and negative charge distribution, which allows them to interact with the polar water molecules. This interaction leads to the dissolution of vitamin C in water. Nonpolar compounds, on the other hand, do not have a charge distribution and do not readily dissolve in water. Fat-soluble compounds dissolve in lipids, not water, and oily substances are generally nonpolar.

Explanation

Vitamin C is a polar compound because it readily dissolves in water. Polar compounds have a positive and negative charge distribution, which allows them to interact with the polar water molecules. This interaction leads to the dissolution of vitamin C in water. Nonpolar compounds, on the other hand, do not have a charge distribution and do not readily dissolve in water. Fat-soluble compounds dissolve in lipids, not water, and oily substances are generally nonpolar.

3. ______ are compounds that form charged particles.

Nonelectrolytes

Ions

Electrolytes

Nonpolar components

Electrolytes are compounds that form charged particles when dissolved in water or melted. These charged particles, called ions, are capable of conducting electricity. This is because electrolytes dissociate into positive and negative ions, allowing the flow of electric current. Examples of electrolytes include salts, acids, and bases. In contrast, nonelectrolytes do not dissociate into ions and do not conduct electricity.

Explanation

Electrolytes are compounds that form charged particles when dissolved in water or melted. These charged particles, called ions, are capable of conducting electricity. This is because electrolytes dissociate into positive and negative ions, allowing the flow of electric current. Examples of electrolytes include salts, acids, and bases. In contrast, nonelectrolytes do not dissociate into ions and do not conduct electricity.

4. Adding a solute to a solvent ____ the freezing point of the solvent.

Raises

Lowers

Does not change

Doubles

When a solute is added to a solvent, it disrupts the regular arrangement of solvent molecules, making it more difficult for them to form solid crystals. This results in a decrease in the freezing point of the solvent. Therefore, the correct answer is "lowers".

Explanation

When a solute is added to a solvent, it disrupts the regular arrangement of solvent molecules, making it more difficult for them to form solid crystals. This results in a decrease in the freezing point of the solvent. Therefore, the correct answer is "lowers".

5. The process in which water molecules draw ions away from a cystalline solid and into solution is ______.

Dissociation

Supersaturation

Concentration

Nonpolarization

Dissociation is the process in which water molecules separate or break apart ions from a crystalline solid and disperse them into solution. This occurs due to the polar nature of water molecules, which have a positive end (hydrogen) and a negative end (oxygen). The positive end of water molecules attracts negatively charged ions, while the negative end attracts positively charged ions, causing them to dissociate and become surrounded by water molecules. This process is essential for the dissolution of many ionic compounds in water.

Explanation

Dissociation is the process in which water molecules separate or break apart ions from a crystalline solid and disperse them into solution. This occurs due to the polar nature of water molecules, which have a positive end (hydrogen) and a negative end (oxygen). The positive end of water molecules attracts negatively charged ions, while the negative end attracts positively charged ions, causing them to dissociate and become surrounded by water molecules. This process is essential for the dissolution of many ionic compounds in water.

6. Which of the following increases rate of evaporation?

Increasing attraction between solvent molecules.

Decreasing surrounding temperature.

Decreasing attraction between solvent molecules.

Combining polar solvents with polar solutes.

Decreasing attraction between solvent molecules increases the rate of evaporation. When the attraction between solvent molecules is reduced, it becomes easier for the molecules at the surface of the liquid to escape into the gas phase. This leads to a higher rate of evaporation as more molecules are able to escape from the liquid.

Explanation

Decreasing attraction between solvent molecules increases the rate of evaporation. When the attraction between solvent molecules is reduced, it becomes easier for the molecules at the surface of the liquid to escape into the gas phase. This leads to a higher rate of evaporation as more molecules are able to escape from the liquid.