PROCEDURE: 

MATERIALS LIST:

• Lime stone –9 samples approximately the same size, flat
• Water- approximately 200 ml (or at least enough to cover the stone)
• Vinegar- 200 ml approximately
• Hydrochloric Acid- 200ml approximately
• 3 glass bowls, tape “HCl”, “Vinegar” and “H2O”
• electric mass scale
• universal paper (pH)
• safety goggles

METHOD:

1.    Label each glass bowl with masking tape. “HCl” for hydrochloric acid, “Vinegar” for Vinegar and “H2O” for water.
2.    Mass each bowl on the electric mass scale and record.
3.    Look for flat limestones to mass (to increase the surface area).

4.    Mass the limestones.  Then group them into groups of 3 with approximately the same mass.
(A=the mass of the rocks).

5.    Place the 3 limestones in each bowl.
6.    Test the pH of each liquid with universal paper.  Record results.

7.    Pour 200ml of liquid into the correctly labeled bowl.

8.    Make observations, record on chart in journal.
9.    Allow the liquid to evaporate over time.
10.                After it has evaporated,

a.   remove the large chunks of limestone,
(B=mass of the rocks after you pour off the liquid and dry them (in the oven at approximately 300 F))

11.                Calculations:   
a.   A - B = C 
Mass of the limestones (A) minus mass of the rocks after the liquid has evaporated  (B)
equals the mass of the residue (C)
b.  To calculate the percentage of material dissolved, for the different liquids, calculate the percentage loss as:  (C/A) x 100

JOURNAL