Home Mixture Separation
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Description

This lab is intended as an open-ended, self-designed activity in which the students are presented only with the problem and a list of equipment available to them. They are required to develop and test out their own procedures. Handouts for HOME use are included but there are no movies because of the open ended nature of the activity.

Objectives

Separating out the different components in a mixture can often prove quite challenging, yet separation and recovery are extremely important operations both for research and for industry. In this lab you have an opportunity to develop and then implement your own self-designed procedure in an attempt to separate out and recover the components of a given mixture. The mixture contains the following four substances: salt, sand, iron filings, and poppy seeds, all essentially in dry granular form.

Safety

Work with a parent or guardian. See the permission below.

Procedure

  1. Obtain from the instructor a sample of the mixture and examine it carefully. Place a small, representative portion of the mixture (no more than 20% of what you are given) in the corner of a plastic sandwich bag, twist it closed, cut it off just above the twist and tape this small plastic sack to the lab sheet in the space below.
  2. Using any materials you want, develop and implement a procedure that enables you to separate out the mixture and recover all four components, each in as pure and dry a state as possible.
    Helpful Hint: If water is part of your procedure, be careful not to use too much!
  3. As each component is separated off, place it in a small plastic sack (as described above) and tape it to this lab sheet in the appropriate space below.

Questions

Analysis & Interpretation

  1. On a separate sheet of paper, in short, concise, numbered steps, write out the procedure you followed. It should be written clearly and thoroughly enough so that anyone not familiar with the lab could reproduce your results simply by reading and following your procedure.
  2. In your estimation, how successful were you (on a scale of 1-10) in separating and recovering each of the four components?
    Sand: ___ Salt: ___ Iron filings: ___ Poppy seeds: ___

Conclusions

  1. What made you decide to do your procedure steps in the order that you did them? Would any order have worked?
  2. If you were to do the lab over again, what specifically might you do differently?
  3. For each of the four components, describe a specific physical property that enabled you to separate it from the rest of the mixture.
    salt -
    sand -
    iron filings -
    poppy seeds -

Extensions

  1. What might you do to determine the purity of each of your recovered components?
  2. How might you separate out each of the following 2-part mixtures:
    1. lead filings and iron filings?
    2. sand and gravel
    3. sand and Styrofoam (both very finely ground)
    4. salt and sugar?
    5. alcohol and water?
    6. nitrogen and oxygen?

Handout

Name ___________________________ Class _______

Teacher __________________________

BeckerDemos 052 Home Mixture Separation

Do the following experiment with one or both of your parents or guardians. Have him/her/them sign it below to confirm that they worked on it with you from beginning to end. NO SIGNATURE, NO CREDIT!

Signature of Parent(s)/Guardian(s): ____________________

Introduction:

Separating out the different components in a mixture can often prove quite challenging, yet separation and recovery are extremely important operations both for research and for industry. In this lab you have an opportunity to develop and then implement your own self-designed procedure in an attempt to separate out and recover the components of a given mixture. The mixture contains the following four substances: salt, sand, iron filings, and poppy seeds, all essentially in dry granular form.

Materials:

Procedure:

  1. Obtain from the instructor a sample of the mixture and examine it carefully. Place a small, representative portion of the mixture (no more than 20% of what you are given) in the corner of a plastic sandwich bag, twist it closed, cut it off just above the twist and tape this small plastic sack to the lab sheet in the space below.
  2. Using any materials you want, develop and implement a procedure that enables you to separate out the mixture and recover all four components, each in as pure and dry a state as possible.
    Helpful Hint: If water is part of your procedure, be careful not to use too much!
  3. As each component is separated off, place it in a small plastic sack (as described above) and tape it to this lab sheet in the appropriate space below.

SEPARATED AND RECOVERED COMPONENTS

representative portion of mixture

salt sand iron filings poppy seeds

Curriculum-

This laboratory fits into discussions of mixtures. Use it to introduce separations of substances.

Activity-

Safety-

Time-

Teacher Preparation: 10 minutes

Class Time: 40-50 minutes one day and 15 to 20 minutes a second day.

Materials-

(Per Group)

[The 120 g of the mixture can be made by mixing approximately 30 g of each of the four components in a large zipper-seal plastic bag. It may be dispensed to the students in stoppered test tubes, each containing 1-2 g of the mixture.]

(Per group)

At each lab station:

(Per Class of 30)

Additional equipment at a central lab table:

This list of additional equipment can be modified as the teacher sees fit, but it should remain extensive,

Disposal-

Dispose of samples with ordinary trash.

Lab Hints-

Observations-

There are hundreds of different procedures that students could use to separate out and recover their mixtures with varying degrees of success, and for any procedural step there are countless refinements and improvements possible. One possible procedure is:

  1. Spread the mixture out on a paper towel.
  2. Wrap a magnet in a piece of cellophane.
  3. Pass the magnet over and through the mixture, shake loose any non-iron granules. Repeat this technique to remove as much of the iron as possible.
  4. Unwrap the magnet, keeping the iron inside the cellophane. Iron is now separated and recovered.
  5. Fold a piece of filter paper in quarters and place it in a filter funnel.
  6. Transfer the remainder of the mixture from the petri dish to a test tube. Add 4-5 mL of distilled water; stopper and shake for 30 seconds to dissolve the salt.
  7. Unstopper, swirl and decant the supernatant into the funnel, allowing the filtrate to drain back into the petri dish. Add 3-4 more mL of water to the test tube, swirl and decant into the funnel, again catching the filtrate in the petri dish.
  8. Set the petri dish aside overnight to allow the water to evaporate.
  9. Remove the filter paper from the funnel -- it should contain the poppy seeds. Allow them to dry overnight. They have now been separated and recovered.
  10. Place a second sheet of filter paper in the funnel, hold the test tube upside down over the funnel and use a plastic pipet to squirt a few milliliters of distilled water up into the test tube to flush out the sand. Allow the funnel to drain into the sink.
  11. Remove the filter paper from the funnel -- it should contain the sand. Allow it to dry overnight. The sand has now been separated and recovered.
  12. After the water has evaporated from the petri dish, use the plastic spoon to scrape as much salt as possible from the inside of the dish. The salt has now been separated and recovered.

Answers-

The Analysis & Interpretation Questions, the Conclusion Questions, and the Extension Questions are, in keeping with the spirit of the lab, all very open ended. Extension question #2 has these possible answers: a) magnet b) screen or sifter c) flotation (in water) d) perhaps by use of a solvent that could dissolve one but not the other or by flotation in some dense nonpolar liquid e) distillation f) distillation

Key Words 1-

solubility, magnetism, solute, solvent, separation, filter, filtration


This static was created at 12:38:59 PM on Friday, April 17, 2015