Saturated and Unsaturated Solutions
Is there a limit to the amount of solute that will dissolve in a solvent?
We use solutions every day. People who wear contact lenses use “lens solution” to rinse their contacts and keep them wet. Athletes who consume sports drinks after exercising benefit from the electrolytes in those solutions. This activity will explore whether or not there is a limit to how much of one substance can dissolve in another.
Model 1 – Saturated and Unsaturated Solutions
1. Which illustration below represents
a. solute particles in a solid state in water?
b. solute particles in an aqueous state?
2. What variables are controlled in all five beakers of Model 1?
3. Count the particles present in each beaker of Model 1. Fill in the table to show the number of dissolved solute particles and the number of solid solute particles.
4. Consider the beakers in Model 1.
a. Which beakers represent unsaturated solutions?
b. Which beakers represent saturated solutions?
5. Beakers A–E in Model 1 are depicted as representing five different or separate solutions. They could also be considered as five “snapshots” of the same beaker over time. In other words, if additional measured quantities of solute were stirred into beaker A in small increments over time, then beakers B–E would result.
a. When a small amount of additional solute is added to an unsaturated solution, what happens to the number of dissolved particles? Provide specific evidence from Model 1 to support your answer.
b. When a small amount of additional solute is added to a saturated solution, what happens to the number of dissolved particles? Provide specific evidence from Model 1 to support your answer.
c. Predict what would happen if a small amount of additional solute were stirred into beaker E in Model 1.
6. Have each person in your group provide an example of the word “saturated” as it is used in an everyday context. Summarize the meaning of the word in the space below.
7. Use a grammatically correct sentence to explain why beakers D and E in Model 1 are labeled as “saturated.” Be sure to incorporate the words “solute” and “solvent” in your explanation, and reach a consensus within your group.
8. What feature in the beakers in Model 1 would typically enable a student to distinguish a saturated solution from an unsaturated one simply by looking at the beaker?
9. Beaker C in Model 1 is shown as “saturated.” Explain why this is the correct category for beaker C even though the typical feature listed in Question 8 is not present.
10. If you were handed a beaker containing a clear solution (with no solid solute at the bottom), and asked to identify it as “saturated” or “unsaturated,” what simple test could you perform to determine the answer.
Model 2 – Solute Dissolved vs. Solute Added
The following data refer to an experiment in which a measured mass of solid is added to 10.0 g of
20 °C water. The mixture is stirred and allowed to sit for 3 hours. Ten separate trials are...