Laboratory

Experiment 4 - Observations of chemical change Data Table 1: Reactions Expected | | Well #/ Question | Chemicals | Reaction | | | | A | NaHCO3 – CO2 | It creates bubbles, it keeps uncolored | B | HCl and BTB | It changes to a strong yellow liquid | C | NH3 and BTB | It changes to blue liquid | D | HCl and blue dye | It changes green. | E | Blue dye and NaOCI | it first is blue and after add the HCl creates several colors, which are yellow, blue and green | F | NaOCl and KI | First a soft yellow, and after add the starch it changes to a black liquid. | G | KI and Pb(NO3)2 | It changes to a strong yellow liquid which seems to be more heavy. | H | NaOH and phenolphthalein | It gets a strong purple color | I | HCI and phenolphthalein | The change of the liquid from no-color to white shows that´s an acid, if it gets combines with a base like the number h the color became strong. | J | NaOH and AgNO3 | It creates brown crystals and all the liquid gets brown. | K | AgNO3 and NH3 | It has no changes, when the chemic get combine but whit the light exposition the paper towel gets brown. | L | NH3 and CuSO4 | It becomes light blue and it seems heavier |

F | rise | black | presence of starch | | plantain | yellow | no presence of starch | | lettuce | yellow | presence of starch | | chicken | black | no presence of starch | Changes
Questions

Use what you learned in this lab to answer the following questions:
A. Suppose a household product label says it contains sodium hydrogen carbonate (sodium bicarbonate). How would you test this material for the presence of sodium bicarbonate?

B. You know what color phenolphthalein and bromothymol blue turn when testing an acid or a base. Use the empty pipet in the Auxiliary Supplies Bag to test several (at least 3) household items including household cleaning products with bromothymol blue. Rinse the pipet well before using it on the next household chemical. When finished with this experiment rinse the pipet well and return it to the Auxiliary Bag for use in future experiments. Name the items tested and record heir results. What do these results mean?

C. You found a sample of a solution that has a faint odor resembling vinegar. You are verifying that it is indeed vinegar and you add a few drops of phenolphthalein. The sample turns pink. What assumption can you make about this sample?

D. While performing a starch test on several different cookie brands, four tests result in the typical black color of starch-presence, but the fifth gives a yellow-brown color. How might you interpret this result?

E. You decided to investigate if the new wave of Vitamin Water is pH neutral: neither too acidic nor too basic. Using BTB (bromothymol blue), you select five flavors of Vitamin Water to test. Three of the flavor-samples turn a murky green, indicating the likelihood of acid/base balance. Of the two remaining, one turns slightly yellow, while one remains blue. What can you assume about the acid/base content of these particular flavors of Vitamin Water?

F. You have read that a new brand of hair tonic is supposed to contain lead (an ingredient in Grecian Formula). Devise a simple test to confirm the presence or absence of lead in that hair tonic.