Beacon Lesson Plan Library
Mystery of the Eleven Unknown Substances
Jo Ann Parsons
DescriptionThis is an easy outline for students to follow for identification of eleven white substances that are commonly found in the household.
ObjectivesThe student knows that connections (bonds) form between substances when outer-shell electrons are either transferred or shared between their atoms, changing the properties of substances.
MaterialsTest Reagents: you will not be allowed to have more than 50 ml of any reagent!
Phenolphthalein (Laxative tablets)
Isopropyl alcohol (70%) rubbing alcohol
Iodine (Tincture of Iodine)
Vinegar (white Vinegar)
Water (Tap water)
Copper (II) sulfate crystals
Supplies you may use-
Test tubes or spot plates, droppers, funnels, filter paper, pHydrion or litmus paper, spatulas, scapulas, test tube rack and test tube holder. Distilled water, a hand lens, a hot water bath will be needed for each group.
Substances- Sodium chloride (Plain table salt- Uniodized)
Sodium bicarbonate (Baking soda)
Sodium carbonate (washing soda)
Sodium hydroxide (Drain Opener)
Calcium sulfate (Plaster of Paris)
Calcium carbonate (White chalk or calcium supplement tablets)
Fructose (Fruit sugar (Estee Brand)
Sucrose (Table sugar)
Magnesium sulfate (Epsom salts)
PreparationsEquipment set up for each group in each class is time consuming. Be sure you have plenty of materials to go around.
Fructose may be hard to find. Try a Natural Food Store.
Make up Benedicts Solution prior to lab.
ProceduresFollow the schematic on the attached handout to observe the properties of the eleven known substances. Then you will receive 2 unknown substances and 1 mixture of three substances to properly identify using the same procedures.
You must never taste materials!!!!!
1. You will fill in the Analysis chart using correct formulas for compound names –Record any notes and observations you would like to make on the process in your lab notebook.
2. You must write balanced and net equations for each reaction taking place in any test unless I tell you otherwise.
3. You must write down why reactions produced color changes, precipitates, or other observations.
1. When you have completed the above process you will receive 2 unknown samples chosen from the 11 original substances and 1 mixture with three substances combined to correctly identify. You will be given only 1 teaspoon of any solid.
2. You must write balanced equations and net equations to represent the reaction-taking place in your unknown samples.
3. You must respond orally to 4 questions by explaining “Why” some observation would occur in the Analysis scheme. (I can ask about anything in the lab, not just your unknowns)
Good Luck- Have fun! Pay attention, work together, keep up with your lab group, ask questions, look up answers, and search for clues and information. Learn as much as you can from this opportunity to investigate!
Assessments– Students will be assessed by the correct completion of the Lab Handout, their lab reports containing observations and Net Ionic equations, and by the correct identification of their unknowns. Students will also be assessed by their responses to four questions asked about the lab and by demonstration of proper lab techniques.
ExtensionsMore Extensive Qualitative Analysis Labs or Labs where students are allowed to devise their own Analysis Scheme.
Attached FilesThe Scheme for the lab is attached. File Extension: pdf
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