January 22, 2014
Title: Observation of Chemical Changes
Purpose: To observe properties of chemical reactions and to associate chemical properties with household products.
Procedure: I used different kinds of chemicals to see the chemical changes that occur when they are mixed together.
Data Tables and Observations:
CHEMICALS
REACTIONS
NaHCO3
Bubbles are formed
HCl & BTB
Turns an orange color
NH3 & BTB
Turns a dark blue color
HCl & blue dye
Turns a green color
Blue dye & NaOCl
Turns a light blue color. 1 drop of HCl: teal color
Kl & Pb (NO3)2
Turns a milky, yellow color
NaOH & phenolphthalein
Turns a pink color
HCl & phenolphthalein
Remains clear, no bubble formed
NaOH & AgNO3
Turns a greenish/brownish color
AgNO3 & NH3
Remains clear
NH3 & CuSo4
Turns a light blue color
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? One way you can test for sodium bicarbonate is a litmus test. This is when you find out the substance’s pH level by dissolving the solution in water and dipping a litmus test strip in the water. If the strip has a pH of around 9, the solution you have is sodium bicarbonate. Another way you can test for sodium bicarbonate is a flame test. If you take a small amount of the material you are using and hold it up to a flame and it turns a yellow/pinkish blue color, you also might have 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.