CHEMISTRY
MRS. MENTZER
MYSTERY LAB
Name: _________________________________
A crime has been committed!! The secret recipe for Dave’s Delicious and Delectable Donuts has been
stolen from his bakery. Dave has always been very protective of his donut recipe. He is so worried about
someone finding out his secret ingredient that he has each employee only do one task. That way no one ever
sees a donut made from beginning to end.
At the start of class, we get an urgent call from Dave. He needs us to investigate this crime. When we
appear on the scene, Dave and his employees are gathered together. We are introduced to each of them:
Marilyn – adds the first ingredient – flour
Carol – adds table sugar
Steve – adds salt
Andy – adds baking soda
Russell – adds cornstarch
Julie – sprinkles powdered sugar
Randy – janitor
Dave is in charge of the other steps because he has always been afraid the employees would ban
against him in a donut conspiracy in order to figure out his secret recipe (he is a bit neurotic if
you haven’t noticed!!)
As we investigate the crime scene, we find a mysterious white powder near the vault where the recipe
was kept. We know that identifying this substance will pinpoint the culprit or culprits.
 In your bins are samples of substances normally found at the bakery:
 Baking Soda
 Powdered Sugar
 Borax (a cleaner/detergent)
 Flour
 Table Sugar
 Cornstarch
 Salt
 You also have some materials to use to conduct some experiments on these substances:
 Deionized water
 Bunsen Burner
 Vinegar (an acid)
 Nichrome wire
 Iodine solution
 Beakers
 Red and Blue litmus paper
 Forceps
 Conductivity tester
 Watchglass
Complete the following tests on each known and fill in the attached data table:
TEST 1: Describe the physical appearance of the substance – Answer color, texture, size of particle, etc
TEST 2: Is the substance soluble in water? Use a beaker with approx 10mL of water. Answer very soluble,
partially soluble, or insoluble.
TEST 3: Does the substance conduct electricity when dissolved in water? Answer high, medium, or low.
TEST 4: Is the substance molecular or ionic? Bright light/loud beep = ionic!
TEST 5: What is the pH of the substance when dissolved in water? Use both a piece of blue and red litmus
paper!! Answer acid, base, or neutral
Both strips to blue = Base
Both strips to red = Acid
Neither changes (looks wet) = Neutral
TEST 6: Does the substance react with acid? Answer yes or no, if yes, describe the reaction. Use a titration
plate!!
TEST 7: Does the substance react with iodine? Answer yes or no, if yes, describe the reaction. Use a titration
plate!!
TEST 8: What color does the substance produce when put in a flame? Wet the nichrome wire with water,
place in substance. Put wire in flame.
Do all of the tests on the unknown substance. Put results in data table.
1. What substance(s) were found near the vault?
2. Who is (are) the criminal(s)?
3. Explain in a few sentences how you know.