1. Separating a Soluble and Insoluble Substance
Lesson 15
Separating a Soluble and Insoluble Substance

2. Lesson 15 - Separating a Soluble and an Insoluble Substance
You will focus on two separation techniques that relate to solubility: filtration & evaporation.
You will use a filter to determine which substances will pass through. 2

3. Lesson 15 - COS
1.0
1.1
1.2
1.3
1.4
1.5
6.0
6.1 3

4. Objectives Discuss evaporation as a separation technique.
Filter mixtures containing water.
Design and conduct an inquiry to clean rock salt.

5. Getting Started
Use a magnifying loupe to examine the blue substance for you group’s plastic cup from Lesson 12. Then, answer the following in your notebook.
What do you think this blue substance is?
How did it get there?
Where did the water go?
Predict what you think will happen if you add 25 ml of water to the cup. Record prediction in notebook.
Test your prediction and write your results.

6. Lesson 15 - (1-1) Vocabulary
filtration - the process of separating a solid and a liquid by passing a mixture of the two through a mesh or filter paper.
Filtrate: the part of the solution that goes through the filter.
residue - remains of a substance
sedimentation - the process by which a solid settles out from a solid/liquid mixture….. 6

7. Notes On Separation Techniques
When separating substances, you must select the correct separation technique.
A separation technique is a method used to separate the components of a mixture from each other
There are three main separation techniques.

8. Filtration
If you want to separate insoluble impurities from salt, you use filtration.
In filtration, a filter is used to let soluble solutes and the solvent pass through and large pieces of insoluble impurities are left on the filter paper as a residue.
The soluble parts that pass through the filter are called filtrate.

9. Sedimentation
In sedimentation, large pieces of insoluble substances will settle out of a mixture to the bottom.
Then, the liquid part can be poured off, leaving the sediment.

10. Evaporation
To separate a solid solute from a solvent, you would use evaporation.
In evaporation, water is allowed to evaporate from a solution. As water evaporates, the solution becomes more concentrated and it becomes more saturated and eventually crystallizes.

11. Evaporation
If you want small crystals, you need to increase the temperature so your solution will evaporate quickly.
If you want large crystals, you need to let your solution evaporate slowly, so you need a lower temperature.

12. Desalination
In deslination, sea water is heated to boiling. The vapors are collected and allowed to condense in a separate collection chamber where it is turned into fresh water. The salt is left behind as a solid.

13. Lesson 15 -
Question
How can you separate soluble and insoluble components of a mixture? 13

14. Lesson 15.1
Hypothesis
If….. then…. because… 14

15. SAFETY
Wear your safety goggles at all times.

16. Lesson 15.1 - Procedure Gather materials. Construct a data table.
Mix water and copper sulfate and filter it through a funnel.
Record observations.
Repeat with zinc oxide and water. 16

17. Copper (II) sulfate and water
15.1 Filtering a Solution
Continue to Procedure for Inquiry 15.2
Results
Mixture
Prediction
Result
Copper (II) sulfate and water
Zinc oxide and water 17

18. Lesson 15.2 - Procedure Gather materials. Construct a data table.
Mix water and rock salt and filter through a funnel into a test tube.
Pour the contents of the test tube into a petri dish. Observe over a few days.
Record observations. 18

19. Lesson 15.2
Results for 15.2 19

20. Lesson 15 -
Conclusion
Filtration can be used to show that insoluble substances will not pass through a filter.
Solutions (the solvent and the solute) will pass through a filter.
Evaporation can be used to recover a solid from a solution.
The rate of evaporation could be increased by heating, increasing the surface area, or increasing airflow over the surface of the solution. Dissolving the solute in the least amount of solvent greatly reduces evaporation time. ………….. 20