Discussion Questions: 1.) When testing with water, what physical property was being identified? When testing the powders with water, the physical property of solubility was tested. 2.) Which items appeared to be water soluble? The items that appeared to be water soluble were the baking soda, the unknown substance, cornstarch, and possibly the baking powder (hard to tell because it mostly became bubbles that stayed and didn't go away). 3.) Which items were not water soluble? The items that weren't water soluble were the cream of tartar, detergent, and possibly the baking powder (reason explained in question #2). 4.) What chemical change was identified using the red cabbage juice? The chemical change that was displayed in the red cabbage juice portion of the experiment were changes in color (based on acidity). 5.) Which substances reacted with iodine? The substances that reacted with iodine were the baking soda (small yellowish color change), baking powder (iodine solidified), corn starch (iodine also solidified), and the unknown
(yellowish color change). 6.) Summarize the results and findings in reference to the original question and hypothesis
(Identify an unknown by physical and chemical properties by comparing observations made about known substances with those made about the unknown). Please include what the identity of the unknown substance was and provide 3 pieces of evidence from your table. Make sure to include any errors or mistakes that happened during the experiment. Lastly, if you have any further questions with regards to the experiment this is where they should be placed.
From the experiment, many different properties were found about an unknown using 5 other known substances. Based on the findings from the other substances (baking soda, baking powder, cream of tartar, detergent, and cornstarch) it could be best guessed that of the known substances, the unknown substance was baking soda. Reasons for this hypothesis is the fact that baking soda reacted with the 4 liquids (water, vinegar, red cabbage juice, and iodine) in the most closely related ways to the unknown substance being: When water was added it dissolved which ruled out cream of tartar and detergent. In the red cabbage juice it turned a bluegreen color which ruled out cornstarch, and when iodine was added, the iodine didn't solidify which of the last 2, ruled out baking powder. That left baking soda as the only substance to be the unknown and therefore baking soda is the unknown substance.
There were only a few errors and mistakes that happened during the experiment. One of them being that occasionally 12 extra drops of a liquid were added and another being that the powders weren't especially easy to put into the different holes and were sometimes spilled. A few mistakes happened where not enough or the wrong information was