Pre lab Questions: (4pts.)
1. What are the learning goals of this lab?
To be able to interpret underlying microscopic in terms of the behavior of atoms & molecules. To be able to separate mixtures into their component substances by solubility.
2. What is the meaning of chemistry?
The identification of the substance of which matter is composed and the identification of their properties and the way they interact.
3. What are the common observations of chemical changes?
Usually irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance.
4. Write the name of one acid and two base used in this lab
5. How would you clean up, if you spilled the acid during the experiment
1st blot up any remaining chemical in the well with a paper towel.
2nd rinse out the 24 and 96- well plates.
3rd dry them with towels.
4th rinse your hands with soap and water.
6. What happens when (what are the products formed?) Baking Soda reacts with Hydrochloric acid? – forms carbon dioxide bubbles.
7. How would you take care of your itchy eyes, after rubbing your finger against the eyelids during or just after the experiment?
1. Title: 1pt
Observations of chemical changes
2. Procedure: 2pts
Set up data table
Using 96-well plate for each combination, place 2 pipet drops of the first chemical and 2 of the other chemical.
Observe the mixture against white and dark backgrounds by slipping white and black paper underneath the well plate.
For each reaction record the well number of the mixture.
3. Observations: 11pts.
Name of Chemicals Mixed
Observations ( in white paper)
Observations ( in black paper)
NaHCO3 + HCl
Bubbles of carbon dioxide not so visible.
Carbon dioxide a lot more visible.
HCl + BTB
Brighter orange color developed.
Dimmer orange color visible.
NH3 + BTB
Color changed to yellow.
HCl and blue dye
Dark green color.
Blue dye + NaOCl, 1 drop of HCl
Blue and green color with a drop of very ligh orange in the middle.
Just looks blue with a tint of green.
NaOCl + KI, 1 drop of Stratch
Colors a lot more visible dark color layer on top and lighter layer at bottom.
Looks all black
KI and Pb (NO3)2
Mixture made a light orange color
Bright orange a lot more visible.
NaOH and Phenolpthalein
Solution made a violet color
Color of violet but looks darker