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

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

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

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

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.

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

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.

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.

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.

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.

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.

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.

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

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

SAFETY Wear your safety goggles at all times.

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

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

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

Lesson 15.2 Results for 15.2 19

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