Factors Affecting Solubility

1. Which method below will not speed up the rate of salt dissolving in water?

Increasing the surface area of the solute

Decreasing the temperature of the solvent

Stirring the solute into the solvent

Heating the solvent before adding the solute

Decreasing the temperature of the solvent will not speed up the rate of salt dissolving in water because solubility generally decreases with decreasing temperature. When the temperature decreases, the kinetic energy of the particles decreases, resulting in fewer collisions between the solvent molecules and the solute particles. As a result, the rate of dissolution decreases, and it takes longer for the salt to dissolve in water.

Explanation

Decreasing the temperature of the solvent will not speed up the rate of salt dissolving in water because solubility generally decreases with decreasing temperature. When the temperature decreases, the kinetic energy of the particles decreases, resulting in fewer collisions between the solvent molecules and the solute particles. As a result, the rate of dissolution decreases, and it takes longer for the salt to dissolve in water.

2. 15 g of sugar cubes are dissolved in 120 g of water at 20^o C. What could be done to increase the rate of dissolution?

Use larger sugar cubes

Stir the mixture

Cool down the water

Add an electrolyte to the water

Stirring the mixture can increase the rate of dissolution because it helps to increase the contact between the sugar cubes and water. When the mixture is stirred, it creates turbulence in the liquid, causing the sugar cubes to break down and mix with the water more quickly. This allows the sugar molecules to spread out and interact with the water molecules, leading to a faster dissolution process.

Explanation

Stirring the mixture can increase the rate of dissolution because it helps to increase the contact between the sugar cubes and water. When the mixture is stirred, it creates turbulence in the liquid, causing the sugar cubes to break down and mix with the water more quickly. This allows the sugar molecules to spread out and interact with the water molecules, leading to a faster dissolution process.

3. Which statement best describes a supersaturated solution? A solution which -

Contains more solute than is normally possible.

Has equal amounts of solute and solvent.

Could possibly dissolve more solute.

Has dissolved the maximum amount of solute.

A supersaturated solution is a solution that contains more solute than is normally possible at a given temperature and pressure. This means that the solution is holding more solute than it should be able to dissolve, creating an unstable condition.

Explanation

A supersaturated solution is a solution that contains more solute than is normally possible at a given temperature and pressure. This means that the solution is holding more solute than it should be able to dissolve, creating an unstable condition.

4. In order for a solution to be an electrolyte, the solute must

Be a molecular compound.

Restrict the flow of electricity

Create a saturated solution.

Consist of positive and negative ions.

An electrolyte is a substance that conducts electricity when dissolved in a solvent. This is because it consists of positive and negative ions that are free to move and carry electric charge. A molecular compound, on the other hand, consists of neutral molecules held together by covalent bonds and does not dissociate into ions in solution. Therefore, for a solution to be an electrolyte, it must consist of positive and negative ions.

Explanation

An electrolyte is a substance that conducts electricity when dissolved in a solvent. This is because it consists of positive and negative ions that are free to move and carry electric charge. A molecular compound, on the other hand, consists of neutral molecules held together by covalent bonds and does not dissociate into ions in solution. Therefore, for a solution to be an electrolyte, it must consist of positive and negative ions.

5. Which of the following will dissolve at the fastest rate?

15 g of sugar cubes in 120 g of water at 60o C.

15 g of sugar cubes in 120 g of water at 20o C.

15 g of granulated sugar in 120 g of water at 60o C.

15 g of granulated sugar in 120 g of water at 20o C.

Granulated sugar dissolves faster than sugar cubes because it has a larger surface area exposed to the water. Additionally, at higher temperatures, the kinetic energy of the water molecules increases, leading to faster dissolution. Therefore, 15 g of granulated sugar in 120 g of water at 60o C will dissolve at the fastest rate.

Explanation

Granulated sugar dissolves faster than sugar cubes because it has a larger surface area exposed to the water. Additionally, at higher temperatures, the kinetic energy of the water molecules increases, leading to faster dissolution. Therefore, 15 g of granulated sugar in 120 g of water at 60o C will dissolve at the fastest rate.

6. At what temperature would carbon dioxide gas, CO₂(g), be most soluble in 100 g of water?

10 degrees C

25 degrees C

80 degrees C

100 degrees C

Carbon dioxide gas is most soluble in water at lower temperatures. As the temperature decreases, the solubility of gases in water generally increases. Therefore, at 10 degrees C, carbon dioxide gas would be most soluble in 100 g of water.

Explanation

Carbon dioxide gas is most soluble in water at lower temperatures. As the temperature decreases, the solubility of gases in water generally increases. Therefore, at 10 degrees C, carbon dioxide gas would be most soluble in 100 g of water.

7. The graph below illustrates the solubility of potassium chloride in water at a variety of temperatures. At what temperature does 30 g of KCl dissolved in 100 g of water create a saturated solution?

10 degrees C

20 degrees C

30 degrees C

40 degrees C

According to the graph, at 10 degrees C, the solubility of potassium chloride in water is approximately 30 g/100 g of water. This means that at this temperature, 30 g of KCl can dissolve in 100 g of water, creating a saturated solution.

Explanation

According to the graph, at 10 degrees C, the solubility of potassium chloride in water is approximately 30 g/100 g of water. This means that at this temperature, 30 g of KCl can dissolve in 100 g of water, creating a saturated solution.