distillation

The substance in the mixture with the lowest boiling point vaporizes first, travels through the tubing and then is condensed in the test tube that sits in the cool water.

The material that remains in the distilling flask is known as the residue.

The substance that travels through the tubing and is later condensed in the test tube is known as the distillate or condensate.

The apparatus for distillation can be more sophisticated than the one shown here. Check the web or various textbooks to discover other setups for distillation.

Websites to check:

One (msn encarta)
Two (encylopedia.com)
Three (demonstration)
Four (M.T. Tham - chemical engineer)

Activity

You are going to make a mixture of a solute and water. Then you will perform a distillation on this mixture to show that you can obtain the water from the mixture. If you have another student on site with you or have been in contact with another student online, arrange for one of you to do the salt and water mixture while the other does the copper (II) sulfate and water mixture.

Part 1: Make the mixture

Make a mixture by placing some of your chosen solute in 50mL of water. Your chosen solute should be either soil or copper (II) sulfate.

Place the mixture in a volumetric flask. Put a few boiling chips in the flask.

Soil and water

Copper (II) sulfate and water

Copper (II) sulphate solution in a flask

Part 2: Perform a distillation on your mixture

Set up the distillation apparatus.

Perform a distillation on your mixture.

Allow the distillation process to continue until you have collected half a test tube of distillate.

Soil and water

Copper (II) sulfate and water

Picture of the distillation of a soil suspension

Picture of the distiallation of a copper (II) sulphate solution

Part 3: Record your observations

Write a description of your original mixture, the distillate and the residue.

Share your results with a classmate.

Find a classmate who did a different mixture and record their observations of their distillation.

Assignment

Hand in your observations of the original mixture, the distillate and the residue for both the soil/water mixture and the copper (II) sulfate/water mixture. Also give a written answer to each of the following questions.

1.	What substance was the distillate in all of the distillations that were done by your classmates?
2.	If the distillation was allowed to go until no more original mixture remained in the flask, what substance would be left as the residue in the flask for the: a. soil and water mixture b. copper (II) sulfate and water mixture
3.	What type of mixture is the: a. soil and water mixture b. copper (II) sulfate and water mixture.
4.	In general, a. what characteristic must the substances in the mixture have before the mixture will be able to be separated using distillation? b. what types of mixtures could be successfully separated using the process of distillation?
5.	What practical uses are there for the process of distillation. That is, for what purposes or applications is the distillation process used in our society today? Explain.

Hand in the answers to your questions. Remember to echo the question in each of your answers.

Assessment

Your score will be based on your answers to your questions as well as your set of observations from your distillation of your mixture. See the answer key to the assignment questions.

Distillation process: explanation accurate and complete (10 marks)

Questions: accurate and complete (10 marks)