Factors affecting solubility

By crushing the solute to smaller pieces the amount of surface area for the solute to contact the solvent INCREASES.

The more solute/solvent interactions that occur the faster will be the rate of dissolution!

This is why Kool-aid is such a fine powder!

***Important to note that molecular bonds are NOT being broken, the molecules are just in smaller pieces.

Size of solute - explained

Draw

Circle the seltzer that will dissolve the most quickly. Then, write an explanation of WHY it will dissolve the most quickly using the terms "surface area", "solvent" and "solute"

Open Ended

Write an explanation of WHY it will dissolve the most quickly using the terms "surface area", "solvent" and "solute"

Agitation - Recap

Stirring or agitating a solution increases the amount of solute/solvent interactions mechanically.

Increasing solute/solvent interactions increases rate of dissolution.

This is why you stir the Kool-aid when you add it to the water.

Draw

Label the solute and the solvent. Then, write a description about how agitation is effecting the rate of dissolution.

Open Ended

Write a description about how agitation is effecting the rate of dissolution.

Watch video in projector

This video is about How TEMPERATURE affects the rate of dissolution.

Temperature - Recap

• Increasing kinetic energy (energy of motion) increases the number of solute/solvent interactions.

• Increasing the number of solute/solvent interactions increases the rate of dissolution.

• AGAIN NOTE that for gases, they are actually more soluble in liquids at lower temperatures, because they boil out when the temperature is too high.

Draw

Circle the container with the most kinetic energy. Then, write a description about the effect of increasing kinetic energy on the rate of dissolution.

Open Ended

Write a description about the effect of increasing kinetic energy on the rate of dissolution.

​Exemplar

Heating a solution increases the kinetic energy of the solution. This will increase the rate of dissolution, because the solute and solvent will be interacting or "bumping" in to each other more, causing the solute to dissolve more quickly.

Match

Match the following terms:

• Increasing agitation

• Crushing solute

• Temperature increase

Mechanically increases number of solute/solvent interactions to increase rate of dissolution

Increases surface area of solute to interact with solvent to increase the rate of dissolution

Increases kinetic energy of solute and solvent particles to increase rate of dissolution

• Mechanically increases number of solute/solvent interactions to increase rate of dissolution

• Increases surface area of solute to interact with solvent to increase the rate of dissolution

• Increases kinetic energy of solute and solvent particles to increase rate of dissolution

Open Ended

List 3 ways to increase the rate of dissolution of a solute AND DESCRIBE each.

Big Idea

To increase the rate of dissolution, you can:

-stir

-crush the solute

-heat the solution

Why do these all work? It is all about increasing solute-solvent interactions. The more the solute and solvent interact, the more quickly the solute will dissolve.

Stirring manually makes the solute and solvent bump into each other more.

Crushing the solute creates more surface area of solute to bump into the solvent more.

Heating the solution increases the kinetic energy of the solution, which means the solute and solvent will be moving around more and will bump into each other more.

Open Ended

Exit ticket time!!!

Ramen flavoring is designed the way it is to ensure easy dissolution for you, the Ramen eater.

Describe in complete sentences how each of the ways we just learned to increase rate of dissolution are exemplified in Ramen flavoring packets.

Exemplar...

​The flavor packets have very small, fine pieces of solute (flavoring). That creates a lot of surface area for dissolution. You place the flavoring in hot water and stir, which also contributes to the quick dissolution of the flavor packet.