Vivian Poon / P3

September 19, 2006

Lab Report: the Mystery Powder

Introduction:

        We have been given a container of mysterious powder that was retrieved from a top secrete crime scene. What the powder is, we do not know. It is up to us to reveal the container’s contents through various types of experiments and tests. For now, we will label the powder as “Mystery Powder O”.

Hypothesis:

        I believe that if we drip different types of chemicals into samples of powders that are similar to that in the container, then we will be able to determine the contents.

Variables:

        Independent variables: the different powders we test

        Responding variable: the reactions of the powder mixtures

        Controlled variable: the sample of our Mystery Power O

        Constant variables: the types of chemicals, the testing environment, the amount

of chemicals we use, the amount of sample powders we use, and the types of

material we use

Materials:

        1.  Goggles                                             7.  Citric Acid

        2.  Well Plates                                        8.  Sodium Bicarbonate

        3.  Spatula                                              9.  Starch

        4.  Iodine                                                10.  Sugar

        5.  0.1m HCL Hydrochloric Acid            11.  Salt

        6.  Sodium Carbonate                             12.  Mystery Powder O

Procedure:

1. Gather needed materials.
2. Using the spatula, distribute three scoops of citric acid evenly between three well plate indents.
3. Repeat the previous step five more times with the other types of powder: sodium bicarbonate, starch, sugar, salt, and Mystery Powder O.
4. Take the iodine and drip two drops of the chemical into one sample of each of the six powders.
5. Record the findings in the observation table.
6. Repeat step 4, but with hydrochloric acid in place of iodine.
7. Record the findings and observations.
8. Repeat step 4 with sodium carbonate as the test chemical.
9. Record the results of the experiment.
10. Analyze the data that was collected and come to a conclusion.

Data:

Powder Observations

Analysis:

When we dripped iodine into a sample of citric acid, the chemical seeped through to the areas of powder that were not initially affected by the drops. The powder turned yellow and dissolved into the iodine. For the sodium bicarbonate sample, the areas of the powder where the drops landed began to compact together. Unlike the other samples, the sample of starch turned black after we applied drops of iodine. The powder turned hard and sticky afterward. The salt sample formed more crystals than it had before, or else they were more clearly defined by the iodine. The whole sample of salt turned yellow. The sugar sample dissolved into a liquid, a mixture between the sugar and iodine, but was not as watery as the citric acid sample. As for the Mystery Powder O, when we applied iodine, the powder dissolved into a yellow liquid, much like the citric acid.

        After applying hydrochloric acid to the sample of citric acid, the drops of chemical quickly seeped through the rest of the powder from the center outward. When applied to a sample of sodium bicarbonate, the powder became harder and began to solidify. When we dripped hydrochloric acid into a sample of starch, the powder turned sticky. For the salt, the hydrochloric acid made the powder crystallize or made the crystals more defined. The powder also became a little transparent. The sugar sample dissolved into a liquid, but some crystals were still visible. The Mystery Powder O sample dissolved in a radial direction when hydrochloric acid was dripped into the middle.

Bubbles began to quickly form when we added sodium carbonate to the sample of citric acid. When we added the same chemical to sodium bicarbonate, the powder hardened. We did the same thing for the starch sample, and the sample turned yellow. The chemical began to slowly absorb into the powder and became dry. When sodium carbonate was applied to the salt sample, the powder became more transparent and crystallized, or else the crystals were more defined. With the sugar, the powder dissolved into the chemical. The Mystery Powder O sample bubbled and fizzed after the chemicals touched the powder.

Resolution:

        I believe the contents of Mystery Powder O is citric acid. The hypothesis I had presented earlier was proven to be correct, if the mystery powder is indeed what I believe it to be. I have come to my conclusion because of the results of our experiments. Out of the five types of powders we had tested, the only one our mystery powder was similar to in the way they reacted to different chemicals was the citric acid samples. There was nothing that went against my belief that the mystery powder was citric acid. In my opinion, the experiment went quite well, though it would have been fun heating the powders to see how they would react. Alas, we ran out of time.