Observation Of Chemical Changes Lab Report

Michelle Felton
Observation of Chemical Changes
June 17, 2014
Chem 107
Purpose:
To associate chemical properties with household products
To observe some properties of chemical reactions Procedure: Using a 96 well plate and a pipette each chemical was placed into its individual well, two drops of a second chemical were added and the observations of the reaction/changes were recorded. The new mixture was viewed on a light and on a dark background to observe all changes. Data Table 1: Reactions Expected
WELL # / QUESTION
CHEMICALS
REACTION
A
NaHCO3 and HCL-CO2
Bubbles form at bottom of well and rise to top of well then burst.
B
HCl and BTB
Clear solution and blue solution turn yellow when mixed
C
NH3 and BTB
Clear solution and blue solution
remain blue
D
HCl and blue dye
Clear solution and blue solution turn green when mixed
E
Blue dye and NaOCl
Blue solution and clear solution remain blue
F
Kl and Pb(NO3)2
Two clear solutions turn bright yellow and liquid appears to thicken when viewed on white paper
G
NaOH and phenolphthalein
Clear solution and blue solution turn pink when mixed
H
HCl and phenolphthalein
Clear solution and blue solution turn foggy green when mixed
I
NaOH and AgNO3
Two clear solutions turn brown when mixed
J
AgNO3 and NH3
Two clear solutions turn silver grey when mixed.
Liquid mixture appears to thicken when mixed
K
NH3 and CuSO4
Two clear liquids turn to pearly blue when mixed

Observations from procedure: BTB remains blue when exposed to a base and turns yellow when exposed to an acid. Phenolphthalein turns grey when exposed to a base and pink when exposed to an acid. Both chemicals turn a murky or foggy green when neutral.

Questions:
a) To test for sodium bicarbonate we could use hydrochloric acid. The two form bubbles when mixed. These bubbles are carbon dioxide.
b) I tested 3 cleaners, Windex, Lestoil, and green cleaner with bleach alternative. (My husband saw the cleaners out, smelled them in the air and actually took me to dinner because he believed that I spend the day cleaning the house.) All 3 cleaners were exposed to BTB and Phenolphthalein to determine if the cleaners were acidic or basic. All 3 cleaners were greenish bluish showing that they are neutral. I am confident that this is so that the products are not liable for any skin irritation or pet/child danger from these products.
c) When phenolphthalein is exposed to an acid it turns pink, therefore vinegar is an
acid.
d) I would conclude that the drinks are neither basic nor acidic. That they are all in fact neutral, I would also conclude that food dye such as blue dye would interfere with the results of the tests.
e) To test for lead I would use Potassium, the combination of the two would turn the solution to a thick yellow solution. I wondered if this would work for lead paint, so I did a quick internet search and sure enough this would work on solid dried paint chips as well.

Conclusion:
Chemistry may in fact be an art.
Although we cannot see individual atoms and molecules reacting, we can often see indications that chemical changes are taking place. Frequently chemical changes are observable through color changes, the formation of a solid or formation of gas bubbles.