3RD FORM CHEMISTRY: SEPARATION OF MIXTURES STEM LESSON (BOOKLET)

Duration: 12 weeks of Term 1

4 or 5 students in a group

Introduction:

Since mixtures form a part of our everyday lives, the separation of these mixtures into components part is important. Examples include the purification of drinking water and the making of filter coffee. If you were stuck on a desert island without any drinking water, your knowledge of separating mixtures could help you make pure water from sea water.

Mixtures are a type of matter where the components can be separated by physical means. The method by which a mixture can be separated into its components parts is determined by the physical properties of these parts, example – particle size, density, solubility and boiling point.

Tasks:

(1) Define key words:

(i) filtrate _______________________________________________________________

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(ii) residue

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(iii) distillate _____________________________________________________________

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(3 marks)

(2) Explain the difference between miscible liquids and immiscible liquids. Give an example of each type of mixture. (3 marks)

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(3) Research how to separate the following mixtures:(i) Pure water from sea water(ii) Ethanol and water(iii) Oil and water(a) Make an oral or video presentation to your teacher of your findings. Your

presentation must not be more than 10 minutes long and you will not be allowed to use any notes! (TOTAL MARKS:22)

Your presentation MUST include the following for EACH mixture:

(i) The name of the separation method used and why you chose it (the physical properties on which the separation method is based) (6 marks)

(ii) A description of the process of separating the mixture with the aid of a large, labelled diagram (to be done on Bristol board). (4+4+4=12 marks -*2 marks for each diagram and 2 marks for adequate coverage of each process)

Also note that in addition to the content above presented, you will also be marked on quality of presentation- speaking clearly and group member participation.

(3 marks)

(b) Complete and submit the STEM self-evaluation rubric to your teacher. (1 mark)

(4) You are provided with a mixture of sand and salt from your teacher. (i) Plan and design an experiment to separate the mixture. (5 marks for method)(ii) At home or in the lab, carry out the method of separation that your group

designed. Record any relevant observations. Present evidence of your separation of the different components to your teacher (1 mark).

(iii) Write a one/two-page lab report on your experiment under the following headings – date (1), title (1), aim (1), apparatus (2), materials (2) method (now in the past tense and any mention of volumes employed – 2 marks), observations (3) and discussion/conclusion (8). Your discussion/conclusion must state the methods of separation used and why (4), explanation of your observations and any key terms identified (4). (20 marks)

DATE: ___________________________________________________________

TITLE: __________________________________________________________

AIM: ____________________________________________________________

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APPARATUS: ____________________________________________________

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MATERIALS: ____________________________________________________

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METHOD: _______________________________________________________

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OBSERVATION: __________________________________________________

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DISCUSSION/CONCLUSION: ______________________________________

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(iv) Complete the ‘Reflection’ handout individually and submit to your teacher. (1mark) TOTAL 27 MARKS

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(5) (i) Define chromatography. (1 mark)

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(ii) In chromatography, substances are separated based on two physical properties. What are these two properties? (2 marks)

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(iii) Chromatography is used extensively by forensic scientists in their work. Research and give two examples of this. (2 marks)

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(iv) Define Rf. (1 mark)

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(v) Research how to calculate Rf values (text books, YouTube or ask an Upper School Chemistry student for assistance). Complete and submit the Rf and analysing chromatograms worksheet. You will need a calculator. (20 marks – write answers on this handout)

(vi) Using the following materials, design an experiment to separate the colours in a black ink pen: water soluble black ink pen, ruler, pencil, drinking glasses, scissors, filter paper or coffee filter, water, popsicle sticks or pencils, tape or binder clips. (5 marks for method)

(vii) Carry out the experiment. Record observations of coloured components. Construct a table of results for distances travelled by each component. Calculate the Rf values. Submit your chromatogram to your teacher as evidence (1).

(viii) Write a one/two-page lab report on your experiment under the following headings – date (1), title (1), aim (1), apparatus (2), materials (2) method (now in the past tense and any mention of measuring distances – 2 marks), observations (of colours recorded – 1 mark), results – table of distances travelled in cm (2) and discussion/conclusion (8). Your discussion/conclusion must explain your observations (6) and show calculations of Rf values (2).

DATE: ___________________________________________________________

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AIM: ____________________________________________________________

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APPARATUS: ____________________________________________________

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MATERIALS: ____________________________________________________

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METHOD: _______________________________________________________

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OBSERVATION: __________________________________________________

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DISCUSSION/CONCLUSION: ______________________________________

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(ix) Complete and submit the STEM self-evaluation rubric to your teacher (1 mark).(x) Complete the ‘Reflection’ handout individually and submit to your teacher

(1mark).TOTAL 54 MARKS

TOTAL MARKS: 109

You may attached additional sheets of paper or write on the back sheet of this paper if you require more space.

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