Observations of Chemical Changes

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Data Tables:
Part 1:
ChemicalsWell No.Observations of the Reaction
A.NaHCO3 + HCl
A1Bubbles immediately formed and started popping (not rapidly). This could be seen more easily with the black paper underneath the well plate B.HCl + BTB
C1Once I added the Bromothymol Blue indicator, it turned an orange-like color C.NH3 + BTB
E1The reaction turned dark blue. When Bromothymol Blue reacts with an acid, it turned orange, and when it reacts with a base, the end result is blue. D.HCl + blue dye
G1The reaction turned green.
E.Blue dye + NaOCl
A3The reaction turned blue.
with the 1 drop of HCl
A3The reaction turned from blue to a blotchy bowl of blue, green, and yellow. Similar to oil not mixing with water, the colors didn’t initially mix but were segregated. The yellow color eventually won out and it slowly turned very pale. F.NaOCl + KI

C3The reaction turned brown, but slowly lightened to a tan color.
with 1 drop of starch
C3The reaction turned black immediately when adding the drop of starch. G.KI + Pb(NO3)2
E3The chemical combination turned the mixture a bright yellow that looked thick and cloudy. The precipitate was yellow at the bottom of the well plate. H.NaOH + phenolphthalein
G3I observed a dark pink color.
I.HCl + phenolphthalein
A5The mixture turned cloudy but clear. I now have the expectation that when phenolphthalein is mixed with an acid, the mixture will remain somewhat clear, and when it’s mixed with a base it will turn a dark pink color. J.NaOH + AgNO3

C5The reaction turned a thick brown color – almost like chocolate milk. K.AgNO3 + NH3
E5The reaction was clear.
after exposure to bright light
I sat this outside to get direct sunlight. It turned dark brown and it looked as though the silver nitrate and ammonia separated on the paper towel. L.NH3 and CuSO4
G5The reaction was a cloudy light blue color. With time it slowly separated into white/blue segments. Part F: Testing of Various Foods with the NaOCl + KI solution

FoodsPresence or Absence of Starch
ApplePresence – turned yellowish/brown
TortillaPresence – turned black
Whole Wheat BreadPresence – turned black
GoldfishPresence – turned black
SalmonAbsence
TurkeyAbsence
PotatoesPresence – turned black

Part 2:
Household Chemicals with Bromthymol Blue

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 their results.

Household ChemicalsWell No.Observations of the Reaction
WindexA7Turned a dark navy blue – almost black.
409C7Turned bright blue.
PalmoliveE7Turned yellow.

Conclusion:

The primary objective of this lab was to observe the macroscopic changes that occur in chemical reactions. From these observations, I learned to interpret the changes and have a better understanding of why I see different reactions between different mixtures.

I was forced to look closely at each chemical reaction to see, hear, and smell the changes that occurred. I can infer that each element and chemical reacts different with each other. For example, potassium iodide reacts one way with sodium hypochlorite (brown/tan) and another way with lead nitrate (bright cloudy yellow). Given this, I learned the importance of making sure I was mixing the correct chemicals, because one mistake could greatly change the end result. Similarly, I also learned how mixing certain chemicals can help indicate an acid or a base. While the mixture may not tell me the exact chemical from visual observation, I was able to deduce if certain solutions were a base or an acid do to its reaction. For example, if I mix Bromothymol Blue with a solution and it turns orange, I’ll...
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