Chemical Nostradamus

You are about to work in a “detective chemical team”. You have to solve the mystery of an unidentified substance found in the laboratory of a famous scientist who has disappeared.

The substance was found at the site of his last experiment and is the key to unlocking what the scientist discovered before he disappeared.

The substance is a white powder that dissolves in water. What could it be?

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Tasks to be performed:

• Analyse the sample taken from the scientist’s laboratory.
• Follow the analysis procedure described below, taking very little of the sample for each step.
• Use the materials given to you for analysis – vinegar, NaOH, water, alcohol, test tubes, spirit lamp, test tube clips, matches, beakers, and pipettes.
• Gather clues by carrying out various investigations.
• Record the results in the table.
• You have 20 minutes.

Analysis Procedure:

• Step 1: Physical properties: Record your observations about the colour and smell of the substance.
• Step 2: Test with water: Add some water to the substance. Does it dissolve? What do you observe?
• Step 3. Test with alcohol: Does it dissolve? What do you observe?
• Step 4: Test with bases: Drop some sodium base on a sample of the substance. Do you observe a reaction taking place?
• Step 5: Reactions with acids: Drop some vinegar on the substance. Observe if there are bubbles. If there are, the substance may be bicarbonate of soda.

• Present your version of what the substance is and what the scientist discovered before his disappearance. Justify yourself. ……………………………………………………………………………………………………………………………………………………………………………………….…………………………………………………………………………………………………………………………………..…………………………………………………………………………………………

To download: Worksheet 2. Chemical Detectives